The Garden Shed

A Community Newsletter published by the Piedmont Master Gardeners

October 2018 - Vol.4 No.10

 

---

• 
  Hedging Our Landscaping Bets

Lemongrass Sauce

In the Vegetable Garden — October

The Ornamental Garden in October

A Hydroponics Primer

Abelia–Tough But Beautiful

October Opportunities

For comments, questions or suggested topics for future Garden Shed articles contact us at: garden-shed@piedmontmastergardeners.org.

If you have specific gardening questions or need help to solve a gardening problem, our Horticultural Help Desk is a free community resource and can be contacted at 434-872-4583 or by email: albemarlevcehelpdesk@gmail.com.

---

Who We Are

We are members of the Piedmont Master Gardeners, which simply means we have all been trained to share the scientific expertise of Virginia Tech and the Virginia Cooperative Extension Service. More important, we are your friends and neighbors with a passion for gardening – and learning more about it. MORE

Table of Contents

Recipe of the Month

Lemongrass Sauce

By Cate Whittington

Ease into Thai cooking with this simple and versatile lemongrass sauce.

Tasks and Tips

In the Vegetable Garden — October

By Cleve Campbell

October is paranoia season in the garden . . .

Tasks and Tips

The Ornamental Garden in October

By Susan Martin

October is the "Countdown Month" for must-do garden chores.

In the Edible Garden

A Hydroponics Primer

By Ralph Morini

A Compelling Story for Home Gardeners, Commercial Growers and a Hungry Planet

Feature

Hedging Our Landscaping Bets

By David Garth

When hedges frame our yards they can do more than mark boundaries because their mass directs our vision, keeping attention on what we've planted within the hedge as well as masking distractions on neighboring property.

In the Ornamental Garden

Abelia–Tough But Beautiful

By Susan Martin

A workhorse from early summer through fall, it offers flowers and colorful foliage.

Upcoming Events

October Opportunities

By Cathy Caldwell

Learn about shade gardening, shop for a household treasure, and learn about being a Master Gardener

Search this site:

Read past issues

Back Issues

Join Us in the Garden Shed

Get notified when we post a new issue of our newsletter

Hedging Our Landscaping Bets

• October 6, 2018
• /
• 1 Comment

Sometimes the least-noticed element of yard or garden makes all the difference.  When hedges frame our yards they can do more than mark boundaries because their mass directs our vision, keeping attention on what we’ve planted within the hedge as well as masking distractions on neighboring property.  At the same time, those sometimes nondescript shrubs are protecting us from random children and dogs, they add a contrasting backdrop to lawn and flowers we’ve carefully tended.  Whether it’s a line of ho-hum shrubbery or a magnificent wall of color and texture, these additions to the landscape shape the impression made by all our gardening efforts.  From a tiny parterre bed of herbs or blossoms to the sweeping art of a magnificent estate, hedges enhance the creativity of a gardener the way a carved wooden frame and mat turn an ordinary photograph into artistry.  In this article, we’ll explore how shrubs can prove to be both functional and imaginative.  In theory, anything can make a hedge: tall ground covers, ornamental grasses, flowers or even trees; but we use the word mostly for shrubs, which is the focus today.

Functionality and Hedges

Privacy hedge. Photo: Tom Sulcer

Let’s start with how ordinary plants in a row can serve several purposes.  When my neighbor cleared the lot next door for her new house, my wife realized our garage light and compost pile faced their bedroom windows.  Changing the light was a quick fix.  Then we also set out boxwood, Clerodendron, and a redbud sapling.  The Clerodendron will soon make a 15-20 foot high grouping to hide our compost piles.  The boxwood and redbud add interest.  Along the driveway a row of inkberry shields the electric fencing around an orchard.

A more typical use for hedges marks the boundary between neighbors for privacy or skirts a walkway to the front door.  In both cases plantings soften the lines that define the yard.   Hardscape block walls or paving for a patio becomes more friendly when combined with greenery.  Because evergreens keep their foliage year round, they can serve not only as a visual barrier but also one that protects a home or yard from strong, drying winds and the noise of traffic.

Photo: Acabashi

Although “good fences make good neighbors,” it’s useful to think about what we want to keep in as well as what we need to keep out with hedges.  A thorny barberry or a prickly mahonia can become all but impenetrable while well-maintained boxwoods or privets leave room for visitors to brush by or even squeeze through.  NOTE: Barberries, Mahonia and Privet are considered invasive although they can be useful in certain environments.  That’s a good reminder that hedges will require control or pruning, a subject we’ll address below.  Sometimes a municipality or homeowners association will have zoning or rules that regulate the height of any barrier and its distance from property lines.  Check before planting.

Abelia makes an informal hedge. Photo: Cathy Caldwell

Perhaps the first consideration for any hedge is its purpose.  The ideas here should only stir your creativity.  Some gardeners today are mixing natives with foreign varieties and even adding a topiary specimen for interest.  But before heading for the nursery, walk around your property to get an idea of such factors as exposure to sun and also wind, slope, and rain.  Take the time to send a soil sample to Virginia Tech in order to match specimens that are appropriate for your place and to know what soil amendments will improve results.  These issues will control your choice of plants, how well they prosper, and the amount of maintenance required.   Other practical matters are whether you want a more natural or formal appearance, and the amount of time and/or money you can expend.  Typically, shrubbery and trees require several years to attain the look you want, so noting their growth rate becomes a consideration.   If a move is likely in five years, scale your landscape plan with that time frame in mind.

More Imaginative Hedges

Betty Mongomery: Pearl Fryars Inspirational Topiary Garden

No matter the scope of your garden and yard, there’s probably a cultivar or variety the right size for your needs.  A small parterre may use dwarf boxwoods or lavender to outline sections for herbs in the same way a large arboretum uses euonymus or roses along its paths.  Flowers on a holly or boxwood are small and will normally be a non-factor.  On the other hand, the blossoms on a viburnum bring welcome color toward the end of a hot summer.  The dependable and deep green of a Foster holly or yew supplies a nice backdrop  to bring out your display of annual flowers.

Earlier we mentioned the softening effect of greenery.  A hedge combined with a low wall takes the edge off masonry.  Sharp corners of any kind are eased both for the eye and for whoever uses the lawn mower when a hedge is planted with gentle curves that define the intersection of two lots with a street.

The very blandness of a hedge will take the mind’s eye unconsciously toward a focal point of interest, a particular drift of colorful annuals, an architectural feature or a specimen tree.  On the other hand there’s no reason why a hedge must be devoid of interest in itself.  Different shades of green, textures,and even different species in a less formal hedge are worth considering.  Layering various sizes not only shields a yard, but also makes a display in itself. For those with a more imaginative turn of mind, sculpted hedges are a possibility.

 

This brings us to the important question of maintenance.  From start to finish, planning produces good results.  It’s well to ask yourself how much time and/or money will be expended for care every year in order to get the desired effect.  Maintaining topiary and formal hedges will take work.  Unlike vegetable gardening, producing a hedge is a long-term  investment over years.  A dwarf plant variety that’s left to grow more naturally will take less care than a carefully shaped formal hedge.  If flowers are a feature of the shrub you want to use, you will need to time the pruning to the season that allows buds to best develop for that particular species.  For example, azaleas should be pruned by mid- summer because they will flower on the new growth that begins soon thereafter.

Here are some important pruning tips:

• As soon as the plants are established, we prune more severely if we want to encourage leafy growth all the way to the ground. 
• The top of a more formal hedge needs to be slightly more narrow than it is at the bottom, allowing sunshine to nurture those lower branches, thus hiding the root and stem.
•  As the hedge matures, it’s important to prune so as to leave some greenery on every branch that extends to the outside.
• Remember, the more formal you want your hedge to appear, the more frequent pruning will be required.

Here’s an outline of decision-making:

1. Decide whether you will use deciduous or evergreens for your  particular purpose.
2. Consider the height and spread you want.  Some find it helpful to set up a stepladder in the proposed hedgeline in order to get a clear idea of  where the sight-line will stop.  Do you want to be able to see across the top?
3. Select your plants with your soil analysis close at hand, keeping in mind their nutrient and soil requirements as well as both height and width.
4. Lay out the design on the ground with pegs and string, making as many curves as you desire.  This step lets you better imagine how sharp the curves can be relative to the ultimate size of the species.  Mark the space for each plant, leaving room for roots to spread and crowns to mature over time in order to reach the desired result.
5. Dig holes twice the width of the plant and to a depth that will place the new soil line where it was in the nursery.

Selection of Plants

While almost any shrub or small tree can be used to make a hedge, here are notes on some possibilities; and see the article listed below for problem-free shrubs.

EVERGREENS

Boxwoods show up often in the Piedmont because they prosper in sun or shade and adapt to pruning.  However, they need loose, well-drained soil for their shallow roots.  Read nursery tags carefully for mature size, conditions and characteristics of the many kinds available.

Barberries come with thorns in different species, sizes and shades of color.  William Penn (Berberis x gladwynensis) grows in sun or partial shade, 3-4′ high and 3-5′ wide; deer and drought resistant.  Japanese barberry (Berberis thunbergii) is deciduous and offers color in fall.  Remember the comment about invasives above.

Hollies include our native tree, the American holly (Ilex opaca).  Yaupon Holly (Ilex vomitoria) can be found in different sizes.  Inkberry (Ilex glabra) is hardy and deer resistant; grows in wet or day soils and accepts a range of pH.

Mahonia or Oregon grape has tough, spiny leaves and can be invasive.  The Leatherleaf Mahonia (Mahonia bealei) grows 5×5′ and resists nibbling deer; produces small yellow flowers and attractive blue fruit; does best in shade.

Yews are easily shaped for more formal presentations and come in many varieties.  They are attractive to deer.  Taxus media ‘Densiformis’ grows 4×6′ in moist soil.

Informal hedge. Photo: Cathy Caldwell

DECIDUOUS

Azalea or Rhododendron come as either evergreen or deciduous and in many varieties and colors although deciduous azaleas will often retain leaves that darken into the fall.  Rhododendron catawbiense or Catawba hybrids are recommended for our area.

Forsythia’s yellow flowers announce spring and are one of the toughest shrubs I’ve encountered.  Gold Tide (Forsythia courtasol) is one variety that grows only 1 x 4′ and tolerates deer, clay soils, and black walnut, as do many other forsythia.

Fothergilla flowers summer and fall.  Dwarf Fothergilla (Fothergilla gardenii) grows 1.5 x 4′ in full sun or partial shade, but not so well in heavy soils.  Leaves color in fall.

Hydrangea can be spectacularly showy.  Oakleaf Hydrangea (Hydrangea quercifolia) likes moist, well-drained soils in sun or partial shade to produce large, pyramidal white blossoms, spreading to 4 x 4 ‘.

Privet hedges can be fiercely invasive, the price it exacts for their incredible hardiness.  Fast-growing and inexpensive, but can become leggy.

Viburnums exist in a great range of sizes and shapes.  Leatherleaf Viburnum (Viburnum rhytidophyllum) tolerates our clay and grows 15 x 15′ with large, course leaves and white flowers in late summer.

References

Dirr’s Hardy Trees and Shrubs (Michael Dirr, 1997)

Shrub Pruning Calendar,” Va.Coop.Ext. Pub.No.430/430-462

“Shrubs: Functions, Planting, and Maintenance | VCE Publications,”  Va.Coop.Ext. Pub.No.426-701

“Problem-free Shrubs for Virginia Landscapes,” Va.Coop.Ext.Pub.No.450-236.pdf

 

 

A Hydroponics Primer

• October 6, 2018
• /
• 1 Comment

Hydroponics, plant cultivation without soil, comprises a variety of growing techniques that is scalable for everything from commercial farms to home gardening. Properly grown, hydroponic produce can compete with field grown crops in appearance, nutrition and taste. In addition, it is a resource-efficient production method that is likely to become a key, if not essential, agricultural system in a world with a hungry, growing population and less available acreage for food production. For the home gardener, hydroponics can be a fun hobby that enables us to garden year round, while helping us better understand some of the below-ground mysteries of soil based gardening.

 

Why Hydroponics?

 

It is oversimplistic to think of hydroponics one-dimensionally because it encompasses techniques as varied as rooting a cutting in a vase of water to large scale, multi-level, fully automatic environmentally-controlled commercial operation. But regardless of scale, the practices share common techniques and benefits.

 

Commercially, hydroponics is potentially very sustainable. Growing operations can be located in urban centers, close to markets, eliminating cross country transportation of crops with its attendant carbon footprint. Water can be recirculated, reducing consumption by as much as 90% vs. field growing, thus enabling successful farming even in water-starved desert areas. With proper hygiene, the elimination of soil dramatically reduces the risk of soil borne pests and diseases. Plants are fed using scientifically determined, grower-measured nutrients in solution. There is no problem with over- or under- fertilization or runoff.

Without soil, weeding is a non-issue, eliminating a headache for the home gardener and reducing controversial herbicide use on the farm. In addition, because hydroponic installations can be multi-level and operate year round, output potential per unit area is several times greater than for outdoor soil-grown crops.

 

There is an ongoing debate about the nutritional and taste characteristics of hydroponic produce compared to soil-grown products. The prevailing opinion is that nutrition is a function of what the crop is fed while growing. Hydroponic systems provide a known and optimized formulation of macro and micro nutrients, and studies have shown it to be equal or even superior to soil-grown produce when properly managed.

 

The logic is similar in the taste debate, with the potential advantage of picking commercial crops that are locally grown, at a later stage than if the product must be transported long distances to reach market. There is research underway that aims to directly address taste and other characteristics, including health-promoting “bioactive” qualities by finding ways to more closely match a plant’s soil-grown experience hydroponically. For me, for now at least, the jury is still out on home grown summer tomatoes, but otherwise, in my limited experience, hydroponic produce holds its own on taste as well.

 

In any case, hydroponic food production has many merits and a lot is happening to build on them. At least one respected market research firm placed worldwide hydroponic production at over $21 billion in 2016, growing at a respectable rate of 6.5%. Related research claims that 12% of US tomato production is already grown hydroponically. A google search of anything related to hydroponic growing will yield a long list of books, articles, videos and supplier ads explaining and peddling hydroponic techniques and products. Soilless agriculture is definitely here to stay.

 

How is it Done?

 

The common basis for hydroponic growing systems is that there is no soil; instead, plants are supported mechanically or in an inert growing medium. Plant roots are exposed to nutrients carried to them by water in the form of a thin film or stream, a wicking system, an aerated nutrient pool, a flooded and drained tray or a spray. Here are some popular system concepts.

 

Water Culture: Floating Raft System

Photo courtesy of: hydroponics.name 

A basic system used for lettuces, greens and herbs, water culture systems place plants in an inert growing medium in perforated pots, mounted in a styrofoam raft, floating in a nutrient bath. Note that the solution needs to be aerated, manually with a whisk or via an air pump, to provide adequate oxygen to plants. Limited oxygenation restricts this method to short growing cycle crops. It is not suitable for longer season and vine crops. 

Nutrient Film System (NTF):

In NTF systems, plants are supported in a growing medium within a trough. A constant flowing thin film or stream of nutrient solution is pumped from a reservoir into the trough. The solution passes through the medium into contact with the plant roots. The trough is angled to use gravity to move the solution back to the reservoir or into a separate container for other use.

 

Wicking Systems

Photo courtesy of: homehydrosystems.com 

Wicking systems are simple and don’t require power. They are a popular classroom system for this reason. The plant tray is positioned close to and directly above the nutrient reservoir, to minimize nutrient and moisture transport distance. One end of the wick is in the nutrient reservoir, the other in the growing medium. Solution is transported by capillary action. This system is best for smaller, non-fruiting plants with lower moisture and nutrient requirements.

 

Ebb and Flow or Flood and Drain Method:

Photo courtesy of blogs.cuit.columbia.edu

Plants are supported in an inert medium, in a level tray. Nutrient solution is pumped into the tray, flooding it for a period of time, then allowing it to drain back to the reservoir. The cycles are typically automatically timed and intervals vary by system and plant.

 Aeroponics

Photo courtesy of: verticalfarm.altavista.org

Rather than bathe plants in solution, aeroponics periodically mists plant roots with nutrient solution. Plants are supported mechanically or in an inert medium while roots are allowed to grow down toward the misting nozzles.  

Drip or Trickle Feed Systems

Drip feed systems pump nutrient from a reservoir through small tubes that provide a regular drip irrigation to plants supported in an inert medium. Excess can be recycled and air is pumped into the reservoir to keep the solution aerated. It is important to prevent water pooling at the trough bottom to prevent root rot. Choice of medium should be based on the plant’s drainage preferences.

 

Choosing a Hydroponic Technique

 

The crop to be grown is key to determining which system is most appropriate. Lettuces, arugula, bok choy and basil, for example, which have a crop cycle of 1 to 2 months, can be grown in a water culture system. Longer term crops like vining crops and plants that like sandy or well drained soils need a system that regularly drains nutrients and exposes roots to air. Ebb and Flow or Drip systems are more appropriate for these crops. Aeroponic systems can be effective for many crops; however, they are more complex to manage and require a higher process management commitment from the gardener.

 

Growing Media

 

There are a variety of soilless growing media used in both seed germination and in hydroponic growing systems. Their common characteristic is that they are inert or very slow to decompose to avoid affecting the nutrient delivery while providing a support structure for the plants.

Most gardeners are familiar with soilless media used for seed germination. Peat, vermiculite and pearlite are typical and these materials are also used in hydroponic applications. Other inert, or slow-to-decompose materials like rock wool, coconut fiber, and a lightweight expanded clay aggregate called “grow rocks” are also widely used. The best choice depends on the hydroponic system, the plants to be grown and medium characteristics like moisture and nutrient holding capacity, aeration, particle size and wicking action. Descriptions of these media and their characteristics are available on line or from hydroponics suppliers.

 

Nutrients

 

Options for providing nutrients range from establishing a chemistry lab in your home to purchasing pre-made mixes from a hydroponics supplier. I recommend the latter to start. Purchased solutions must cover the 6 essential macro and 8 micro elements needed by plants. There are different blends for different plants as well as customized blends for vegetative vs fruiting plant stages where appropriate. There is also widespread research underway that attempts to simulate soil-based growing, without sacrificing the precise nutrient delivery of hydroponics. The goal is to optimize the nutrient and flavor quality of hydroponically-grown products. For the beginning home gardener, a standard solution,  chosen in consideration of the crops being grown, makes sense. Controlling the nutrient concentration of the reservoir is essential. An electrical conductivity meter is the tool used to accomplish this task.

 

Non-mineral elements

 

In addition to the essential nutrients mentioned, plants require water, light and air.

Water used in hydroponic systems must be high quality. Processed city water is generally satisfactory. Reverse osmosis or distilled water is great. Sophisticated home systems may include a filter. The pH of the nutrient solution as well as the growing medium will require use of a pH meter to help keep it in the preferred range for the crop to be grown, generally in the 5.5-6.5 range.

Light is sourced from the sun for outdoor installations or from grow lights for indoor systems. LED lighting is very popular now because of the ability to optimize color mix, the relatively low investment cost, and efficiency.

Air is important both above and below the plants. Aerating the nutrient solution and/or providing appropriate aeration to plant roots is essential. Nutrient application cycles and growing medium choices are central to getting this right. Above the roots, the issues are similar to soil based gardening. Good air circulation and plant spacing both come into play. Inside and in greenhouse environments, air movement, temperature and humidity management are important for plant growth and to minimize the likelihood of insect and disease issues. Fully environmentally- controlled systems account for all these factors. Up-front investment is a function of system sophistication. Thus, higher-priced units automate many of the otherwise manually-controlled factors that influence success or failure of the crop.

 

Getting Started at Home

 

Researching this topic was an eye-opening experience, especially discovering the quantity and variety of information and equipment that is available to prospective hydroponic gardeners. The options range from youtube videos showing DIY possibilities to simple herb-growing systems to backyard greenhouses to fully environmentally-controlled furniture-like indoor “hydroponic appliances. ” The home gardener has a multitude of possibilities for taking up the craft.

 

If your head is spinning from all the possibilities and process management requirements, relax. It is easy to start small with an inexpensive purchased system and packaged supplies to grow greens or herbs and learn as you go. Hydroponics system and material suppliers are happy to answer questions and offer guidance. There is little doubt that the prospect of enjoying fresh, chemical-free, locally or home grown produce and vegetables, year round, will drive the growth of hydroponics. The question is whether we, as individuals, will be buyers or growers.

 

Sources:

Hydroponics for the Home Grower, (Howard M. Resh, CRC Press, 2015).

“Home Hydroponics,” Va.Coop.Ext. ext.vt.edu/Pub.426-084.

“Types of Hydroponics Systems,” www.soilless.org/hydroponics/types

www.mordorintelligence.com/industry-reports/hydroponics-market

“Are hydroponic vegetables as nutritious as those grown in soil?” https://well.blogs.nytimes.com/2016/12/23/are-hydroponic-vegetables-as-nutritious-as-those-grown-in-soil/

www.zerosoilgardens.com

www.homehydrosystems.com

Thanks to Babylon Micro Farms, Charlottesville, VA, for the facility tour and explanation of their proprietary “hydroponic home appliance” system.

 

The Ornamental Garden in October

• October 6, 2018
• /
• 1 Comment

I consider October to be the “Countdown Month.” Although some chores can be pushed off to November, I work with one eye on the calendar, one eye on the first frost date, and one eye on the accelerating rush of leaves to the ground.

What tasks should move to the must-do side of our October maintenance lists?

MUST DO TASKS

• Cut back perennials. Refer to the October 2015 article, “Tasks and Tips in the Ornamental Garden” for a list of perennials that should be cut back and a list of perennials that should NOT be cut back.
• Dig up canna lily, caladium, dahlia, tuberous begonia, shamrock (Oxalis), and elephant ear (Colocasia) after the tops are browned by frost. Allow to dry; clean off soil; and store in peat moss or vermiculite in a cool location free from frost.
  

  Red canna lily: SKsiddhartthan, Wikimedia Commons

• Continue to plant spring-flowering bulbs until the ground freezes. Bulbs do best if planted about one month before the first freeze. In our area, there’s a 50% chance of first hard frost (32 degrees) by October 31; a 10% chance by October 13; and a 90% chance by November 18.
• DO NOT PRUNE trees or shrubs unless you are removing dead limbs. You might mistakenly prune off buds that have already set for spring bloom, or you could encourage a late-season blush of growth just when a plant should be getting ready for dormancy.
• Take in any houseplants that still remain outside before nighttime temperatures fall below the mid-50s. Wipe the pots clean of dirt and debris; spray off the plants; and check carefully for any insects.
•  Start conditioning  photoperiodic plants now for rebloom around the holidays. Photoperiodic means they react in a certain way to the daily cycles of daylight and darkness. By manipulating the amount of light they receive, you can control their bloom schedule. Such plants include: amaryllis, Christmas cactus, kalanchoe, and poinsettia. For specific instructions, refer to  “The Ornamental Garden in October,” The Garden Shed, Oct. 2016.
  
• Remove cool-season weeds, such as chickweed, dandelion, wild onion, plantain, and white clover.

MULCHING LEAVES FOR TURF

If you live in a heavily-wooded area, the prospect of raking and disposing of leaves can be daunting. A thick layer of leaves on a grassy area blocks sun­light and reduces turf growth. The leaves also trap and hold moisture, increasing the potential for turf disease. Numerous university research reports have detailed how leaf mulching affects turf performance. In almost every instance, the results show that chopping up deciduous leaves as part of a regular mowing schedule is an effec­tive means of managing leaves without harming the turf. See the report by Purdue University for more details. Michigan State research touted an overall reduction in dandelions and crabgrass over time because the leaf mulch covered empty areas in the turf where weeds could germinate in the future.

Mulch­ing mowers are the preferred equipment for chopping leaves. To reduce the risk of injury from flying debris, remove sticks and limbs before mulching. Wear safety goggles and an air mask over your mouth and nose to protect yourself from debris and dust. Mulching moist leaves minimizes dust concerns, but if leaves are too wet, the mower’s engine will be stressed and the leaves will not be chopped sufficiently small to easily decompose in the soil. Multiple passes with a mower might be required to thoroughly chop leaves. Set the mower height to 3 inches. Sharpening mower blades and keeping air and fuel filters clean will improve the mulching process and extend the life of the mower engine.

MULCHING LEAVES FOR PERENNIAL BEDS

Fallen leaves can be composted, added directly into the soil, or turned into leaf mold (partially decomposed leaves). See Clemson Cooperative Extension, “Soil Conditioning – Establishing a Successful Gardening Foundation”.

Many homeowners collect carbon-rich leaves and add them to their compost piles, where the leaves help to balance the carbon/nitrogen ratio (kitchen scraps are high in nitrogen) and absorb excess moisture. It is best to shred the leaves coarsely, using a shredder or a lawn mower. Whole leaves have a tendency to blow away, while finely-shredded leaves do not allow water to penetrate.

When used on perennial beds, shredded leaves should be spread 2 inches deep or less; even shredded leaves tend to mat together, restricting the water and air supply to plant roots. As leaf mulch slowly decomposes, it provides organic matter which helps keep the soil loose and provides an ideal environment for earthworms and other beneficial soil organisms. This improves root growth, increases the infiltration of water, and also improves the water-holding capacity of the soil. Organic matter also offers essential plant nutrients such as potassium (K), calcium (Ca), phosphorus (P), magnesium (Mg), and boron (B).

To make leaf mold, leaves should be placed in a pile in the fall, and then turned several times in March and April. Over time, shredded leaves naturally break down into a soft, finely-textured substance called leaf mold. This concentrated material is high in calcium and magnesium and retains three to five times its weight in water. After application, it may only last for 1 to 2 years before completely breaking down and moving into the soil. This process adds significantly to the structure and quality of the soil. Leaf mold can be added to vegetable gardens and landscape beds after the soil has been warmed in the spring. Leaf mold can also be added to potting soil, used to top-dress potted plants, or used as a super-premium mulch.

For a detailed discussion on the benefits of mulching, the use of both organic and inorganic mulches, and how to mulch, refer to the Clemson Extension article, Mulching.

WHEN TO MULCH

Organic mulches (leaf, shredded hardwood mulch, pine bark or other organic mulches) used to help moderate winter temperatures can be applied late in the fall after the ground has frozen but before the coldest temperatures arrive. One of the benefits from winter application of mulch is to reduce the impact of freezing and thawing of the soil in late winter and early spring. The repeated cycle of night-time-freezing and warm-day-thawing can cause many small or shallow-rooted plants to be heaved out of the soil. This displacement exposes their root systems and can cause injury or death. Mulching helps prevent the rapid fluctuations in soil temperature and reduces the chances of heaving.

SOIL TESTS

Soil testing in the fall allows time for corrective pH and nutrient management before new growth starts in the spring. Fall sampling also avoids a sometimes busy spring period at the Soil Testing Laboratory, thus avoiding delays in getting soil test results. Fall can often be a wet season.  As a rule, if the soil is too wet to work (or is good for making mud pies), it is too wet to sample. Refer to the VCE publication, “Soil Sampling for the Home Gardener”.  As a general rule, soil tests are recommended every three years, unless you note specific problems that indicate testing.

TREE SELECTION AND PLANTING

Late fall is the best time of year to plant or transplant deciduous trees and shrubs. Transplant when the trees and shrubs are dormant but before the ground freezes. Evergreen trees or shrubs may be transplanted earlier in the fall before they go dormant.

For ideas on which trees to plant in our area, see the article by the Virginia Cooperative Extension, “Problem-free Trees for Virginia Landscapes.” Although these suggested trees may not be 100% problem free, they have been tested in our area for disease resistance and hardiness. The list includes both native and non-native trees as well as a list of trees not recommended for planting in our area.

RECOMMENDED READINGS

The Ornamental Garden in October, The Garden Shed, 10/17, http://pmgarchives.com/article/the-ornamental-garden-in-october-3/

• Look for topics such as: October-blooming perennials; why leaves change color; regulating light for photoperiodic plants such as Christmas cactus and poinsettia,

“The Ornamental Garden in October,” The Garden Shed, 10/16, http://pmgarchives.com/issue/october-2016/

• Look for topics such as: October-blooming perennials; fall maintenance; caring for houseplants.

“The Ornamental Garden in October,” The Garden Shed, 10/15, http://pmgarchives.com/article/the-ornamental-garden-in-october/

• Look for topics such as: which perennials to cut back and which to leave standing, planting cool-season annuals.

“October Tips: Perennials, Annuals and Bulbs,” Virginia Cooperative Extension, https://albemarle.ext.vt.edu/content/dam/albemarle_ext_vt_edu/files/hort-tip-sheets/10-14-perennials.pdf

“October Tips: Trees, Shrubs and Groundcovers,” Virginia Cooperative Extension, https://albemarle.ext.vt.edu/content/dam/albemarle_ext_vt_edu/files/hort-tip-sheets/10-14-trees-shrubs.pdf

SOURCES

“Making Compost from Yard Waste” http://pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/426/426-703/426-703_pdf.pdf

“Spring-Flowering Bulbs,” http://pmgarchives.com/article/spring-flowering-bulbs/

“Making Compost from Yard Waste,” Vir­ginia Cooperative Extension, https://pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/426/426-703/426-703_pdf.pdf

“Leave Them Alone—Lawn Leaf Management,” Virginia Cooperative Extension, http://pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/430/430-521/430-521_pdf.pdf

“Backyard Conservation: Mulching,” https://www.nrcs.usda.gov/wps/portal/nrcs/detail/?cid=nrcs143_023585

“Soil Testing for the Home Gardener,” Virginia Cooperative Extension, http://pubs.ext.vt.edu/452/452-129/452-129.html

“Mulch,” Clemson Cooperative Extension, https://hgic.clemson.edu/factsheet/mulch/

“Soil Conditioning—Establishing a Successful Gardening Foundation,” https://hgic.clemson.edu/factsheet/soil-conditioning-establishing-a-successful-gardening-foundation/

“Problem-free Trees for Virginia Landscapes,” Virginia Cooperative Extension, https://pubs.ext.vt.edu/450/450-237/450-237.html

Abelia–Tough But Beautiful

• October 6, 2018
• /
• 13 Comments

Glossy abelia (Abelia x grandiflora) is often described as a tough plant. In fact, Carol Robacker, one of the horticulturalists involved with the abelia breeding program at University of Georgia, described abelia this way: “Around here, we call abelia the gas station plant. You could plant it beside a gas station surrounded by asphalt and forget about it, and it would still survive and thrive.”

But abelia is not just tough, it’s also beautiful. It adds colorful, fragrant blossoms when most other flowering shrubs have succumbed to summer heat, or to summer dry spells, or have just plain tuckered out.

HISTORY

Abelia, a formerly recognized genus that contained about 30 species and hybrids, was placed in the honeysuckle family, Caprifoliaceae, in 2013. These deciduous and evergreen shrubs are native to eastern Asia (Japan west to the Himalayas) and southern North America (Mexico). The genus name honors Dr. Clarke Abel (1780-1826), physician and naturalist, who collected seed and plants as part of a British expedition to China in 1817. All of Abel’s seeds and plants, however, were lost in a shipwreck on the homeward voyage. Living plants of Abelia chinensis (now Linnaea chinensis) were first imported to England in 1844 by Robert Fortune.

A recent study by Kew Gardens separated the 30 species of Abelia into four genera. New cultivars, especially from the very popular Abelia x grandiflora (glossy abelia), have proliferated, with over 30 mentioned in the literature. A. x grandiflora is a cross between A. chinensis (Chinese abelia) and A. uniflora.

PLANT CHARACTERISTICS

Glossy abelia is a multi-stemmed shrub which features clusters of white, bell-shaped flowers (to 3/4″ long) with a persistent, reddish calyx which gives the flowers a pinkish tinge. Flowers are fragrant and offer a continuous bloom from early summer to fall. Ovate, glossy, opposite, dark green leaves are pinkish when new and turn purplish-bronze in autumn. The bark is exfoliating. A. x  grandiflora prefers an acidic, moist, well-drained site but tolerates clay, damp, or dry soil. A thin layer of mulch is recommended so that the soil can drain. The shrub is generally cold-hardy to about 0ºF., although some varieties are more or less tolerant of extreme cold.   It grows in Zones 6-9, but it reaches a larger size when grown in warmer climates. In Zones 5-6, stems can die back to the ground in winter. It is evergreen, semi-deciduous, or deciduous, depending on the hardiness zone.

On average, the shrub grows 3-6’ tall and wide. Cultivars offer a range of sizes, including dwarf shrubs suitable for containers. Its arching habit does best when left unpruned. However, if you prefer a tidier look, prune in late winter/early spring because A. x  grandiflora blooms on new wood. It can also survive severe pruning if that becomes necessary. Plants occasionally produce tall, vigorous shoots that are typical of the species and not the cultivar (genetic reversion to the parental characteristic). These vigorous shoots should be removed to the base.

ABELIA CULTIVARS

There are many cultivars offering different shrub sizes, flower color, and foliage color that changes from summer through fall. The cultivars are heat and drought resistant. Although they flower best in full sun, they also tolerate partial shade.

Examples of A. x grandiflora Cultivars:

• ‘Rose Creek’  has evergreen leaves that look pinkish when new but turn purplish through late summer. Clusters of fragrant, white tubular-shaped flowers are produced from May through frost. Below each flower is a light pink calyx that imparts color even after the flowers fade. The plant grows into a mounded shape 2-3’ tall and at least 3’ wide with reddish stems. It is an excellent choice for shrub borders and foundation plantings. ‘Rose Creek’ was developed by Michael A. Dirr, University of Georgia.
  

  A. x grandiflora ‘Rose Creek’. Photo: Susan Martin

• ‘Canyon Creek’ is a taller 4-6’ variety with coppery-pink leaves that turn yellow and then green. Light pink flowers bloom throughout the growing season. The shrub is semi-evergreen to deciduous in zone 7. Also developed by Dirr.
• ‘Little Richard’ is a compact plant growing to 3’ tall and wide with abundant small white flowers. New foliage is bright red, then turns a glossy vivid green in summer, and tangerine-pink in fall.
  

  A. x grandiflora ‘Kaleidoscope’. Photo: Forest and Kim Starr

   

 

 

 

 

 

 

• ‘Kaleidoscope’ was discovered in 1997 as a variegated branch sport of A. x grandiflora ‘Little Richard’. ‘Kaleidoscope’ is a dense, semi-evergreen, compact shrub with reddish purple stems. New foliage emerges as green and yellow; turns gold in summer; and then fiery-red-to-orange in fall. Its pink buds open into white fragrant flowers that persist into fall. ‘Kaleidoscope’ grows 2-2.5’ tall and 3-4’ wide. Its smaller size makes it suitable for growing in patio containers, or massed on slopes for attractive shrubby cover and erosion control.

A Sampling of Other Cultivars:

• 

  ‘Edward Goucher’ Abelia. Photo: KENPEI

  ‘Edward Goucher’ was introduced in 1911 by Edward Goucher of the United States Department of Agriculture. A cross between A. x grandiflora and shumannii, the shrub typically grows to 2-3′ tall in colder zones and to 5’ tall in Zones 8-9. It is less cold hardy than glossy abelia and does best in Zones 6a and warmer. Clusters of lavender-pink, funnel-shaped flowers (to 3/4″ long) with orangish-yellow throats bloom from mid-summer into fall. Ovate, glossy, dark green leaves turn purplish-bronze in autumn.

• ‘Raspberry Profusion’, a seedling selection of ‘Edward Goucher’ x chinensis, blooms heavily from May to September. The entire plant is covered with big clusters of strongly-scented, pink flowers with flamboyant raspberry sepals. The sepals remain after the flowers drop, extending the color until the end of autumn. The shrub is robust and compact, growing to 3-4’ tall and wide. It is mostly deciduous in the winter. Developed by Carol Robacker, University of Georgia.
• ‘Lavender Mist’ is also a seedling selection of ‘Edward Goucher’ x chinensis. It’s a heavy bloomer, with clusters of fragrant lavender flowers beginning in mid-June and continuing into autumn. Sepals are a straw-green color at the base, becoming rose at the tips. Summer foliage is gray-green. It grows 3-4’ tall and wide. It is mostly deciduous in the winter. Developed by Carol Robacker and Sloane M. Schreiber, University of Georgia.
  

  Abelia mosanensis in the Botanscher Garten, Berlin. Photo: Krzysztof Ziarnek, Kenraiz

  Abelia mosanensis, fragrant or Korean abelia, is an evergreen or semi-evergreen hybrid species that reaches a height of 4-6’ or more, has especially fragrant flowers, and a shorter bloom period (May to June). Its bright green, ovate leaves often have a bronze or reddish tint when emerging. The flower buds are rich reddish-pink and open to white funnel-form flowers. The obovate sepals often have an attractive pink tint and persist long after the flowers fall. Note: This shrub flowers on old wood, so prune right after flowering.

POLLINATORS

Abelia attracts hummingbirds, butterflies, and bees.

PEST AND DISEASE PROBLEMS

Abelia exhibits no serious pest or disease problems, and is very resistant to deer. It also tolerates air pollution.

OTHER POSITIVES

The Georgia Exotic Pest Plant Council (GA-EPPC) recommends Abelia x grandiflora and glossy abelia cultivars as alternatives to non-native shrubs that are invasive. (The GA-EPPC cautions that invasiveness could become a factor at some point in the future for any of the recommended alternative plants.) This GA-EPPC site provides lists of non-native invasives; non-native alternatives; and native alternatives. There are lists for trees, shrubs, vines, groundcovers, ornamental grasses, and herbaceous perennials.

Abelia x grandiflora is also included on a list of drought-tolerant shrubs compiled by Clemson University Extension in August, 2016.

HOW TO USE ABELIAS

Because of their compact shape, abelias are often used as foundation plants. The taller varieties are used for borders or hedges. The dwarf varieties are suitable for containers or massed on slopes for attractive shrubby cover and erosion control. Abelias’ hardiness and adaptability make them a popular choice for commercial landscapes and for demanding environments such as parking lots.

SUMMARY

If you are looking for a shrub that will keep blooming through the end of summer when most other plants have waved the white flag, consider the abelia. Though not native, it does not exhibit invasive properties. It is deer, pest, and disease resistant. It attracts many different pollinators. It offers a variety of colorful blooms and foliage that evolves in color as the season progresses. Who wouldn’t make space in their garden for such an undemanding, rewarding bloomer?

SOURCES

Abelia, NC State Extension, https://plants.ces.ncsu.edu/plants/all/abelia-x-grandiflora/

“Suggested Alternatives to Non-native Invasive Plants,” Georgia Exotic Pest Plant Council, https://www.gaeppc.org/alternatives/

“Plants That Tolerate Drought,” Clemson University Extension, https://hgic.clemson.edu/factsheet/plants-that-tolerate-drought/

Glossy Abelia, Abelia x grandiflora, Virginia Cooperative Extension, https://pubs.ext.vt.edu/3010/3010-1488/3010-1488.html

Abelia x grandiflora, http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=j150

“Two New Abelias: Beautiful and Deer Resistant,” Moya Andrews, Indiana public media, https://indianapublicmedia.org/focusonflowers/two-new-abelias/

Abelia ‘Edward Goucher’, http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=a930

“The Sweet Smell of Spring: Abelia Mosanesis,” Nancy Rose, Arnold Arboretum of Harvard University, http://arnoldia.arboretum.harvard.edu/pdf/articles/2013-70-4-the-sweet-smell-of-spring-abelia-mosanensis.pdf

Abelia x grandiflora ‘Kaleidoscope,’ http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=359785&isprofile=1&gen=abelia

“New Varieties Provide a Host of Bloom Colors, Plant Sizes,” University of Georgia, https://www.griffin.uga.edu/news/new-varieties-provide-host-bloom-colors-plant-sizes

‘Raspberry Profusion’ and ‘Lavender Mist’: “New Abelia Cultivars for the Landscape,” HortScience, http://hortsci.ashspublications.org/content/41/4/1020.4.abstract

“Abelia: A plant made for Georgia summer, Daily Citizen-News, http://www.dailycitizen.news/news/lifestyles/abelia-a-plant-made-for-georgia-summer/article_229d2687-8db6-555a-8e36-8be1b4921ce6.html

Dirr’s Encyclopedia of Trees and Shrubs (Dirr, Michael, 2011)

Lemongrass Sauce

• October 6, 2018
• /
• 1 Comment

                                                                                                                   

Thai restaurants are often my first choice when dining out as the food is both flavorful and healthy. Since my consumption of Thai food has been largely limited to restaurants, I decided to add a few Thai culinary herbs to my kitchen garden last spring. Thinking that I might be inspired to cook Thai food at home, I planted Thai basil and lemongrass. Having researched neither, I tucked the lemongrass in beside the basil and waited. Imagine my surprise when the lemongrass sprouted like Jack’s legendary beanstalk, concealing the rest of the herbs under its graceful fronds.

The lemongrass plant (Cymbopogon citrates), native to Africa and Asia, has a long history of culinary and medicinal uses. An article in Mother Earth Living (below) offers an exhaustive list of its uses, from treating ringworm and lice to scenting soaps and perfumes, to repelling tigers!

This aromatic plant with its long blue-green, tapered leaves is quite lovely. While it is the wrong plant for my tiny space, I will definitely continue to grow lemongrass. I understand that the plant will overwinter easily in a pot indoors and that I can divide it for planting in the garden next spring. I intend to place several clumps in front of my gas meter to form an attractive barrier.

Lemongrass is very easy to harvest, simply cutting each stalk from the base of the plant. One plant produces an abundance of stalks, resembling somewhat ‘woody’ scallions when cut. With its purported antioxidant qualities, the herb is frequently used for teas or added to broths, much as one would toss a bay leaf into the pot. Other culinary uses include stir fry dishes, curry pastes, and marinades. As its essential oils are in the stalks’ cell walls, the stalks are often bruised by pounding them with a mallet to release the oils. Watch the YouTube video below for instructions on how to prepare lemongrass for a variety of dishes.

The following recipe is one I created after trying out several different recipes for sauces and dressings, each a variation on the same theme. This one uses less sugar and more vinegar than some because I like the sour taste of vinegar, but you may choose to reduce the acidity of the recipe by adding more sugar to taste. I used this as both a marinade for shrimp over Thai noodles and as a dipping sauce for dumplings. I think it would be equally tasty in a rice salad or over poached fish.

          

 

Ingredients

3 Tablespoons minced lemongrass, inner portion

½ cup rice vinegar

2 Tablespoons brown sugar

2 Tablespoons Thai fish sauce

2 Tablespoons lime juice

1 teaspoon soy sauce

1 teaspoon minced scallion

½ teaspoon red pepper flakes

Directions

Combine all ingredients in a bowl. Add  ½ cup cold water and let sit for 15 minutes.

 

 

Resources:

“Herb to Know: Lemongrass,” Mother Earth Living  (February/March 1997,  Betsy Strauch),  www.motherearthliving.com/plant-profile/an-herb-to-know-26

October Opportunities

• October 6, 2018
• /
• 0 Comments

In the Vegetable Garden — October

• October 6, 2018
• /
• 0 Comments

I often associate the months of the year with the seasonal tasks to be performed in the vegetable garden. I usually think of the months of April–May as the planting season, while June–July is the growing season with its maintenance tasks of weeding and watering; August–September is the harvesting season, and October, well, that is my “paranoia” season.

October is paranoia season because in our area, it is the first frost month — usually around the 15th of the month. It can arrive earlier or later, but we know it is going to happen; we just don’t know exactly when. I always have peppers needing just a little more time to turn to that brilliant red or perfect golden yellow, or tomatoes on one plant or the other that are slow in ripening, or that one lettuce bed that is just starting to rock, so I am glued to the weather report, trying to catch that first freeze warning. I can’t count the times we’ve had a frost, and then right afterwards, Indian summer shows up smiling and bringing temperatures in the 70s and 80s for a couple of weeks after all the frost damage is done. I have finally come to the conclusion that waiting for that freeze warning is too late because there are precautions that can be taken to extend the growing season before that dreaded frost forecast.

There are two types of frost, advective and radiation. Advective frost occurs when a cold front sweeps into an area. A radiation frost occurs under calm winds and clear sky, allowing radiant heat from the earth to rise to the upper layers of the atmosphere. With radiation frost, the lack of wind prevents mixing of the air and an inversion develops. An inversion is just a fancy way of saying “things get turned around from the normal.” Normally the air closest to the ground is the warmest, but when an inversion happens, cold air collects near the ground while the warmer air lies above the trapped cold air. During an inversion, cold air is just like water running down a hill — it seeks the lowest point because it is heavier than warm air, and frost pockets may form. The first frost typically is a radiation frost that occurs on a calm, clear night.  

There are several things we can do when a frost warning is issued:

Harvest early: Flowering plants such as beans, tomatoes, peppers, eggplant, squash and okra need to be harvested if there is no way to protect them. Fruit harvested in the mature green stage will still ripen, but sadly will not have the same flavor as a vine-ripened fruit.

Water before a frost: Moist soil can hold approximately four times more heat than dry soil. Moist soil can also conduct heat to the soil surface faster than dry soil, providing some frost protection. A Cornell University study suggests that the air temperature above a wet soil is 5°  higher than that above a dry soil, and in the study, that difference was maintained until 6 a.m. The conclusion of this study was that plants could benefit from watering the evening before a frost.

Cover your plants: A cover can provide anywhere from 2º to 6º F of protection, depending on the type of material used. The covers can be laid right on top of the plants or can be supported by stakes or a frame, the main difference being that there is less frost protection when the cover touches the plant. Any material can be used as cover; however, woven fabrics are better insulators than plastics or paper. The best time to apply covers is in the late afternoon after the wind dies down. Remove the covers the next morning.

 

 

 

 

 

 

 

 

Additional Tips and Tasks for October:

• Plant garlic and shallots to harvest next year.

• Harvest tender herbs (basil) before the first frost. They can be hung to dry in a cool dark place or the leaves can be frozen for use at a later time.

• Thinking about planting a fruit tree? Fall is usually cool and moist and a great time to plant. In addition, you may be able to save a little money, as local gardening centers usually have a fall sale. Water the newly-planted tree to provide sufficient moisture and prevent winter damage. Add a 3-inch layer of organic mulch, such as shredded bark around the base of the plant to retain soil moisture and regulate soil temperature. Research has shown that roots will continue to grow until the soil freezes, which is around late November in Virginia. Stake and wire newly-planted trees only if necessary. Use a piece of rubber hose around the guy wires to protect the trunk. The guy wires should be tied loosely enough so that the tree is able to move a little in the wind. The supports and stakes should be removed once the tree becomes established, usually in a couple of months. (Relf)

• Fall is an excellent time for taking soil samples in your garden. A soil test measures the pH (acidity or alkalinity) of the soil and the levels of some of the major elements required for plant growth, such as phosphorus and magnesium and potassium. If lime is required to adjust the pH, now is a good time to apply it. A free soil test kit is available from your local extension office.

• Pick up dropped fruit from under fruit trees so that deer and rodents will not be attracted to the fruit  — AND to your growing tree. Raking and disposing of diseased leaves will help keep insects and diseases under control next season.

• High grass and mulch are a haven for rodents whose gnawing can severely damage trunks. Keep the grass mowed around new trees.  Be sure that mulch is raked back 3-4 inches away from the tree trunk.

• Tomatoes need an average daily temperature of 65º F or higher in order to ripen. If daytime temperatures are consistently below this temperature, pick the fruits that have begun to change color and bring them inside to ripen.

• Harvest sweet potatoes before frost because cold soil temperatures can reduce the quality and storage capacity of sweet potatoes. I find that removing the vine first makes the digging a lot easier. Also, care should be taken when digging sweet potatoes because they skin and bruise very easily.

• When removing disease-infested plants or debris, do not place this refuse on the compost pile. The disease pathogen may continue to live in the compost pile and may be transmitted when the compost is applied to the garden.

• After frost, cut back all the foliage of asparagus to within 2 inches of the ground.

• There is still time to plant a winter rye cover crop. A cover crop protects the soil over the winter, traps any unused nutrients to prevent them from leeching, and adds organic matter in the spring when tilled under.

• It’s not too early to start thinking about next year’s garden. An excellent tool for planning is a garden sketch of this year’s crop locations. This will help when you’re deciding  which crops you need rotate to minimize disease problems. Vegetables crops in the same botanical family are often susceptible to the same diseases and insects. For crop rotation to be effective, gardeners should not plant vegetables belonging to the same family in the same location for at least two or three years. Obviously, crop rotation in a small garden may be difficult. However, we should rotate our vegetable crops as best we can.

Thanks for stopping by The Garden Shed; we look forward to your visit next month.

 

Sources:

Phillips, Ben, “Freeze Damage in Fall Vegetables: Identifying and Preventing,” http://msue.anr.msu.edu/news/freeze_damage_in_fall_vegetables_identifying_and_preventing

Relf, Diane, Virginia Cooperative Extension, “The Virginia Gardener Newsletter,”Volume 23, Number 9/10, 2004, page 7.

Colorado State University, Publication GMG #722, “Frost Protection and Extending the Growing Season,” http://cmg.colostate.edu/Gardennotes/722.pdf