The Garden Shed
A Community Newsletter published by the Piedmont Master Gardeners
March 2015 - Vol. 1 No. 3
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.
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Table of Contents
Tasks and Tips
The Ornamental Garden in March
It’s March and the ornamental garden is emerging from its long winter sleep.
In the Ornamental Garden
The Eastern Redbud is one of the stars of the spring landscape.
Feature
Colorful Native Hardwoods for the Landscape
Adding colorful native hardwoods to the landscape
March Lawn Care
As spring comes closer, gardeners are anxious to get outside. And for many of us, spring is the time to start working on our lawns. There are a few tasks to do in March but don’t get overly anxious, especially not with fertilizer. Spring is a perfect time to perform a soil test, including separate ones for your back and front lawn. This should be done about every 3 years — prior to adding any supplements for the season.
The Charlottesville-Albemarle Extension Office now offers a new program called Healthy Virginia Lawns. A trained Master Gardener will come to your site, measure your lawn and assist with collecting the soil test. When the results are received, they will contact you with a nutrient management plan. For further information, call 434-872-4580 or email hvl.albemarle@vt.edu. In next month’s newsletter, there will be an in-depth article on soil testing, including how to collect the soil properly and how to interpret the results. If you are anxious to do it this month, consult Soil Sampling for the Home Gardener, Virginia Cooperative Extension publication at: http://pubs.ext.vt.edu/452-129/.
Seeding
Spring is not the ideal time to establish cool-season grasses such as fescue because in spring, fescue has a minimal amount of time to develop an extensive root system before the heat of summer. However, there are circumstances that require spring planting, such as new construction or bare patches. Optimize your chances of success by selecting a seed variety that suits your situation, such as shade or sun. Plant when soil temperatures are 55°-65°F, and till to a four to six inch depth in compacted areas. For success, be sure to have good soil preparation and sufficient watering. For a complete discussion, go to http://pubs.ext.vt.edu/426-718/. Lawn reseeding will be discussed further in the fall newsletter because fall is the optimal time of the year for renovating your lawn.
Weeds
Dr. Shawn Askew, Virginia Tech’s Extension Turfgrass Weed Specialist, says the absolute BEST weed control in the lawn IS the lawn. In other words, if we manage our lawn appropriately, the weeds will be reduced. Weeds are often an indication of problems in the grass environment. If we can determine the underlying problem, we may be more successful. For example, knotweed usually indicates compacted soil. Thus to solve the problem or at least reduce it, aeration of the lawn is needed.
Crabgrass
Photo by Ed Rascallie
Classification of Weeds
Lawn weeds can be divided into 2 classes — weedy grasses such as crabgrass and quackgrass, and broadleaf weeds such as dandelion, clover, knotweed and plantain. These two classes are further subdivided according to the length of their lives. Perennial weeds have a lifetime of over 2 years. Annual weeds germinate from seed, grow, flower, and produce seed in less than 1 year. Summer annuals germinate in the spring and mature in the fall. Winter annuals germinate in the fall or late winter and mature in the spring. Knowing this, you can see why timing of mechanical removal and remediation is essential for eradication.
Dandelions
Photo by Robert Taylor
Cultural practices
The University of Maryland Extension office has suggested the following cultural practices for a healthy turfgrass.
• Maintain proper soil pH – A soil test should be taken every 3 years to determine pH. Soil pH should be in the 6.0 to 6.8 range for optimal turf growth. Apply lime according to soil test results to achieve the desired pH.
• Fertilize at the proper time – Fall fertilization is recommended to encourage root development. If turf lacks dark green color and is weak and thin, a light late-spring application of fertilizer is also beneficial. Fertilizer should not be applied in the summer when turf is dormant and possibly under stress from hot, dry conditions. Do not bag grass clippings. Clippings that decompose on the lawn will not cause thatch to develop, but will recycle nutrients. Less fertilizer will need to be applied to your lawn.
• Irrigate only if necessary – Watering lawns is usually prohibited during a prolonged drought. Allow established tall fescue lawns to go dormant during hot, dry weather in the summer. The lawn will recover when rainfall and cooler temperatures return. Only newly seeded areas and lawns less than two years old should be irrigated.
• Mow at proper height – Close mowing weakens turf by removing too much leaf surface. Try to mow frequently enough that you remove no more than 1/3 of the blade at one mowing.
• Amend poor soil conditions by aerating compacted soil, adding organic matter to poor soil, and correcting drainage on poorly-drained sites. Aeration is best done in the fall. Spring is a wetter time and disturbing wet soil results in more compaction. Spring aeration opens up the soil for weed seeds to germinate.
• Use the proper seed for your site conditions – For sunny sites, plant turf-type tall fescue. In shade, plant fine fescue such as chewings fescue, creeping red fescue, or hard fescue.
• Buy quality seed – When buying seed, choose cultivars recommended by the Maryland-Virginia Turfgrass Variety Recommendation Work Group. Virginia and Maryland work together each spring evaluating which seed is the best for our area. http://www.pubs.ext.vt.edu/CSES/CSES-17/CSES-17.html. Check the grass seed label for the percentage of weed seeds. Percentage by weight of weed seeds should be less than 0.1%. Higher percentages indicate a poor quality grass seed. Avoid buying seed that contains any percentage of noxious weeds such as Cirsium arvense L. (Canada thistle), Poa annua L. (Annual bluegrass), or Dactyllis glomerata L (Orchardgrass.)
• Overseed to fill in thin or bare spots – Overseed in late August through early fall. The next best time is in early spring.
• Remove thatch – Thatch prevents water, air, and nutrients from reaching the soil. Thatch buildup tends to be more of a problem on Kentucky bluegrass and fine fescue lawns. If thatch is present, you will notice a brown layer of non-decomposed organic matter between the soil and the grass. If this layer is thicker than 1⁄2 inch, thatch removal is recommended. Thatch should be removed in the fall, while the turf is actively growing. Rent a vertical mower or core aerator for this task.
Identification of Weeds
I’ve been asked by many what spring weeds look like. For pictures of common spring weeds go to “Spring Weeds,” https://extension.umd.edu/hgic/weeds/spring-weeds.
Ready the Mower
Lastly, March is a perfect time to get your lawn mower ready for summer. Hopefully, it has been put away with the fuel emptied but if not….
- Remove the gasoline. Leftover gasoline from the previous year can become stale, choking the carburetor and causing rust.
- Disconnect the spark plug . This is if you decide to service the mower yourself. It disables the engine, making it safer to perform service on the machine.
- Remove the blade(s). While this piece is removed, sharpen it using a metal file. Sharpen them now, once in the summer and probably in the fall.
- Drain the oil. Four-cycle engines will need to be drained of oil and refilled with fresh oil
- Clean the equipment. Use a putty knife and wire brush to knock off accumulated grass and mud, then reattach the blade if you removed one earlier.
- Replace the air filter. This improves airflow to the engine, allowing it to run more smoothly.
- Replace the spark plug. Although your old spark plug may still work properly, installing a new one is a cheap and easy way to ensure optimal performance.
Insect Control
Most insects’ life cycles have not yet started in March, as the weather is still relatively unpredictable, and is often simply too cold for insects to survive. The vast majority of insect control tasks can wait until a bit later, until April and May.
In summary:
- Perform a soil test and follow instructions for supplements such as lime.
- Correct drainage on poorly drained soil.
- Handpull winter annual weeds
- It is not necessary to fertilize established lawns in the spring
- Take your mower to the shop for servicing and blade sharpening or DIY
- It is too early to treat for damaging insects
Sources:
Gussack, Eva and Rossi, Frank. Turfgrass Problems, Picture Clues and Management Options. Natural Resource, Agriculture and Engineering Services, June 2001.
“Spring Postemergent Lawn Weed Control,” Virginia Cooperative Extension Publication at http://www.ext.vt.edu/topics/lawn-garden/turfgrass/turfandgardentips/tips/spring-postemergent-Lawn-weed-cont.html (this is a podcast that you can listen to; you can also read the transcript)
“Soil Sampling for the Home Gardener,” Virginia Cooperative Extension Publication No. 452-129, http://pubs.ext.vt.edu/452-129/
“Establishing Lawns,” Virginia Cooperative Extension Publication No. 426-718, http://pubs.ext.vt.edu/426-718/
“Preemergent Hericides for Crabgrass Prevention in Lawns,” PlantTalk, University of Colorado State Cooperative Extension, http://www.ext.colostate.edu/ptlk/1541.html
“Weed control in lawns and other turf,” University of Minnesota Extension, http://www.extension.umn.edu/garden/yard-garden/lawns/weed-control-in-lawns/
“Spring Weeds,” University of Maryland Extension, Home and Garden Information Center, https://extension.umd.edu/hgic/weeds/spring-weeds
“Control Options: An Environmentally Responsible Approach to Weed Control,” University of Maryland Extension, https://extension.umd.edu/hgic/lawns/control-options
“Guide to Controlling Weeds in Cool Season Turf,” University of Maryland Extension, Home and Garden Information Center, Publication HG 101, http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG101%20Guide%20to%20Controlling%20Weeds%20in%20Cool%20Season%20Turf.pdf
“2014-2015 Virginia Turfgrass Variety Recommendations,” Virginia Cooperative Extension, http://www.pubs.ext.vt.edu/CSES/CSES-17/CSES-17.html
Eastern Redbud Tree
Redbud trees make me happy. Well, let’s face it, most flowering plants make me happy. But the Eastern redbud tree, or Cercis canadensis, holds a particular charm for me. That’s because it’s one of the first trees to bloom in spring. It provides irrefutable evidence that winter is finally over. Its lavender-pink blossoms serve as a precursor to all the glorious color and pageantry that spring has to offer. These smallish trees are mostly inconspicuous the rest of the year, but they are in their glory when countless thousands of them burst into bloom throughout the eastern half of the United States every spring. If one redbud is a show stopper, then a grouping of them in bloom is truly a joy to behold. Although it shares the spotlight with wild plums, cherries, flowering magnolias, forsythias, dogwoods, quince and other early-blooming species, the redbud clearly steals the show.
The redbud tree bore special significance throughout the early history of this country. According to the Arbor Day Foundation’s website (http://www.arborday.org), “Early settlers found the blossoms of the redbud a delicious addition to their salads. Early folk healers used the bark to treat common maladies and sometimes even leukemia….but the sheer springtime beauty of the redbud may be its greatest hold on the American spirit.”
Eastern Redbud Foliage
Andrea Wulf’s book Founding Gardeners references the redbud as one of the trees George Washington included in his Mount Vernon landscape because it “deserves a place in my shrubberies.” Finding “a great abundance of the red-bud of all sizes” in the forest, he directed that they be dug up and transplanted into his gardens. Furthermore, Wulf states that Thomas Jefferson included the Eastern redbud in his plants at both Monticello and Poplar Forest.
The name of this tree has an interesting bit of history associated with it. A related species found in the Mediterranean, C. siliquastrum, is called a Judas tree based on the belief that it was the tree upon which Judas Iscariot hanged himself after he betrayed Christ. According to legend, the blossoms, which were originally white, turned red either from shame or blood. The name redbud stuck and the tree has been referred to by that name ever since. In Trees of Eastern and Central North America, author Donald Peattie says somewhat tongue in cheek: “George Washington and Thomas Jefferson called it Redbud too, and that should be good enough for any American.”
With such an abundance of redbuds in the wild, they might seem common and ordinary. So why plant them in your landscape? Well, for one thing, their spring-time blaze of color is a pure pleasure to see after months of drab winter colors. For another, the heart-shaped, dark green foliage is graceful and attractive during the summer months. As autumn approaches, the foliage turns a pleasing shade of yellow. Clusters of flat green “pea” pods develop on the branches in the summer, adding additional textural interest to the tree. The pods turn dark brown when mature and persist into winter. The tree’s dark bark, divided trunk, bare limbs, and broadly rounded crown form an interesting and attractive wintry silhouette, particularly when covered with snow. Redbuds add texture and interest to a mixed shrub border, either when grown as a single specimen or as a grouping, and they are particularly appealing in a naturalized setting.
Eastern redbuds are native to the eastern part of the United States and thrive in zones 4 – 9. Members of the Fabaceae or pea family, they are small understory trees that normally grow 20 to 30 feet tall and tend to have a pleasing irregular shape. As the tree ages, it develops a broader vase shape. In early spring, the flower buds display a magenta or purplish-red hue. As the pea-shaped flowers open up, their color softens to a paler lavender-pink or mauve color. The blossoms appear in clusters on new growth, as well as on the trunk and older branches, and persist for about three weeks. Heart-shaped, dark green foliage emerges after the tree finishes blooming.
Redbuds grow in full sun or partial shade and are adaptable to a range of soils, including clay, loam and sand. Although they are hardy and adaptable, they are happiest in moist, well-drained soil. Because redbuds are native to such a large area of the country and are therefore subject to a wide range of growing conditions, it is generally best to acquire a specimen that has been grown locally. For optimum success, choose a small, well-rooted specimen because larger specimens may not transplant successfully.
Despite its name, redbuds are available in more than one color. For example:
- ‘Royal White,’ ‘Alba,’ and ‘Texas White’ are white-flowered forms yet they are still called redbuds.
- ‘Tennessee Pink’ produces clear pink flowers as opposed to the lavender-pink blossoms typical of the species.
- ‘Forest Pansy’ has purple foliage, which is stunning in the spring. The purple foliage tends to green out in the heat of summer, however, and benefits from some afternoon shade.
- ‘Hearts of Gold’ has chartreuse foliage, which emerges orange-red initially. As the foliage matures, it turns a gold-green color, which then fades to chartreuse. This small cultivar generally tops out at about fifteen feet.
- ‘Silver Cloud’ is a variegated green and white cultivar that is about the same size as the species but with smaller leaves.
And then there are the weeping forms.
- ‘Traveler’ is probably one of the better known weeping cultivars. It tops out at around five feet but can spread to ten feet or more in width.
- ‘Covey,’ which is also sold under the name ‘Lavender Twist™’ is another popular weeping form.
- ‘Ruby Falls’ is yet a third weeping form. This cultivar is the result of a marriage between ‘Covey,’ which gives it its weeping form, and ‘Forest Pansy,’ which gives it its purple foliage.
- There’s even a variegated weeping form called ‘Whitewater.’ White and green variegated leaves emerge in the spring and gradually turn mostly green over the growing season.
If there’s a down side to redbuds, it’s that they are short lived in general and may decline after twenty years or so from disease. Despite this dire warning, I have had the great good fortune to see older redbud specimens with limbs that bent down and nearly touched the ground. But those are rare and, should you encounter one, it will take your breath away with its graceful form and beauty. Redbuds decline for a variety of reasons. They are susceptible to fungal diseases, such as Botryosphaeria canker, which encircles the branches, effectively cutting off the water supply to the leaves. Verticillium wilt is another nasty disease that affects redbuds. The Verticillium fungus blocks the tree’s vascular system, rendering the tree unable to move water and nutrients. Pruning out any dead, cracked, or diseased branches about six to eight inches below the diseased area will help control both fungal diseases. It’s important to cut into healthy wood and then disinfect pruners between cuts with rubbing alcohol. Also, a well-watered redbud tree is less likely to succumb to disease than a tree that is stressed by drought.
As for pests, redbuds are subject to a few, such as treehoppers and scale. Treehoppers are seldom serious and an infestation can be controlled by spraying horticultural oil when temperatures are between 35° and 85° F. Scale insects present themselves as crusty or waxy-looking bumps typically on new wood. Scale infestations should be treated with horticultural oil in the spring or early summer if nymphs are present.
Redbuds are not exclusive to the east coast of this country. Two other subspecies of redbud, Oklahoma redbud (C. reniformis) and Western redbud (C. occidentalis), are also native to the United States. Oklahoma redbud is native to the southwestern part of the country (Texas and Oklahoma) and is Oklahoma’s state flower. It tends to be a little smaller than Eastern redbud and has thick, leathery leaves that make it more drought tolerant than the eastern species. Western redbud is native to California, Arizona, Nevada and Utah. It is a drought-tolerant, shrub-like tree with blue-green foliage that tops out around fifteen to eighteen feet tall and wide. To complete the picture, C. siliquastrum (or Judas tree), which I mentioned above, is native to Europe and western Asia. C. chinensis is native to China and Japan. A third non-native species, C. mexicana, is native to Mexico.
Plant expert Michael Dirr sums up the charm of the Eastern redbud in Dirr’s Hardy Trees and Shrubs as follows: “A treasure in the April landscape when its clustered magenta buds unfold a blanket of rosy pink. No equal, no competitor, can be found among small flowering landscape trees—the stage is reserved for this native species.” I quite agree with his assessment. Wonder where I can get a bumper sticker that says “I brake for redbuds!”
Sources:
Arbor Day Foundation (http://www.arborday.org).
Clemson University (http://www.clemson.edu/extension).
Dirr, Michael A., Dirr’s Hardy Trees and Shrubs, 2005.
Field Guide to North American Trees Eastern Region, published by National Audubon Society, 1996.
Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida Environmental Horticulture Department (http://hort.ifas.ufl.edu).
Peattie, Donald Culross, A Natural History of Trees of Eastern and Central North America, 1991.
Virginia Cooperative Extension (http://www.ext.vt.edu) Publication 426-611: Selecting Landscape Plants: Flowering Trees.
Wulf, Andrea, Founding Gardeners, 2011.
Asparagus with Shallot Vinaigrette
- 1 lb. asparagus
- 1/2 cup good quality extra virgin olive oil
- 2 tbs. chopped shallots
- 3 tbs. red wine vinegar
- 1-1/2 tsp. Dijon mustard
- salt and freshly ground pepper
- 2 tbs. chopped parsley
- 2 hard-cooked egg yolks
Snap tough ends from asparagus. Steam spears until tender but still firm. Actual cooking time depends on thickness of the spears. Be careful not to overcook. Arrange on a serving plate.
To make the vinaigrette, whisk together the olive oil, shallots, vinegar and mustard in a small bowl. Add salt and pepper to taste. Add the parsley. Spoon the vinaigrette over the warm asparagus. Use only enough vinaigrette to evenly coat the spears. Use a wooden spoon to force the egg yolks through a fine-mesh sieve over the asparagus. Serves 4.
The Edible Garden Tips and Tasks- March
Well, it’s March, a very welcome month after our near zero temperatures in February. Burrrrrrrrr. March is actually a month of many seasons; it can be cold and snowy, and then there will be a few warm days, but naturally, the warm days are just spring teasers. Regardless of the unpredictable weather, March is the start of the spring garden season, a time to complete those winter tasks we dare not carry over into the spring rush, when there are so many tasks and so little time.
March is also my month of math. Math? What’s math got to do with gardening? Well, for me it’s a count-backwards month for starting seedlings indoors. Here is where the math comes in: a quick review of Virginia Cooperative Extension (“VCE”) Publication No. 426-331, “Vegetable Planting Guide and Recommended Planting Dates,” [1. ubs.ext.vt.edu/426/426-331/426-331_pdf.pdf] indicates that, based on historical data, the last frost in our area usually happens in the last week of April. Several of my experienced, risk-averse gardening friends assume that May 1st is the safe frost-free date in our area. You may wish to adopt this more cautious approach as well. The last frost date is the earliest date when many of your young vegetable plants can be safely planted outdoors. A review of the tomato, pepper, and eggplant packets suggests that the seeds should be started indoors in seed flats 6-8 weeks before transplanting them in the garden, so doing the math, I need to begin starting my seedlings indoors during the first two weeks of March.
Keep in mind that the last frost date may vary a bit, depending upon the unique conditions of your gardening site. Does your site have southern exposure, a colder exposure, or is it low-lying in a frost pocket? Remember, just like water, cold air flows downhill. Also, unusual weather is always a possibility, and a surprisingly-late killing frost is not unheard of around here! Also, the last frost date is really an estimate based on analysis of the historical data.
As a general rule, according to the Virgina Cooperative Extension guidelines (Publication No. 426-331), the following vegetables can be planted in our area during the month of March:
| First Week In March: | Second Week In March: | |
| Asparagus | Asparagus | |
| Collards | Collards | |
| Garden Peas (English) | Garden Peas (English) | |
| Radishes | Radishes | |
| Spinach | Spinach | |
| Turnips | Turnips | |
| Leeks | ||
| Mustard | ||
| Potatoes | ||
| Onion Sets | ||
| Third Week In March: | Fourth Week In March: | |
| Asparagus | Asparagus | |
| Collards | Collards | |
| Garden Peas (English) | Garden Peas (English) | |
| Radishes | Radishes | |
| Spinach | Spinach | |
| Turnips | Turnips | |
| Leeks | Leeks | |
| Mustard | Mustard | |
| Potatoes | Potatoes | |
| Onion Sets | Onion Sets | |
| Beets | Beets | |
| Carrots | ||
| Broccoli* | ||
| Cabbage* | ||
| Cauliflower* | ||
| Swis Chard | ||
| Bibb Lettuce | ||
*Denotes Transplants
Keep in mind that these are only suggested planting times, as seed germination often depends on soil temperature. Many seeds, such as spinach, lettuce, and beets, require a soil temperature in the 55-60 degree range to germinate. Also, transplants need to be “hardened off” by placing them outdoors daily in a sheltered area (out of direct sunlight) or in a cold frame for about two weeks before transplanting them into the garden. During the hardening off process, the plants will need to be brought back indoors or otherwise given ample protection from chilly night temperatures.
Often seed catalogs and seed packets indicate a planting time, sometimes using the phrase,“as soon as the soil can be worked.” One simple test to determine if the soil can be worked is to squeeze a hand-full of soil into a ball. If the soil holds together in a wet or sticky ball, it’s too wet to work.
Not sure what vegetables or specific varieties of vegetables to plant? Look at VCE Publication No. 426-480, “Vegetables Recommended For Virginia,” which provides a comprehensive listing of recommended varieties. VCE 426-480
Containers from the kitchen can be recycled for starting seeds indoors. Aluminum trays from frozen food just need a few holes poked in the bottom to provide drainage. Other possibilities include cottage cheese and yogurt containers, milk or ice cream cartons, styrofoam egg cartons, paper cups and plastic salad containers. All should have drainage holes.
If you use vermiculite to start seedings, the seedings should be transplanted to a soil mixture when the plants develop the second pair of leaves, because the vermiculite medium lacks the nutrients for sustained plant growth.
March is a good time to begin a compost pile, if you have not done so already. Most garden centers or nurseries sell composting bins. For more help in planning you compost bin, contact your local Cooperative Extension office or view Virginia Cooperative Extension Publication No. 442-005 at VCE pub 442-005.
Spring fertilization of fruit trees should occur about 3-4 weeks before active growth begins. Scatter fertilizer evenly under the tree, starting about 2 feet from the trunk and extending just beyond the drip line. A soil test should be performed prior to applying fertilizer. For information on how to perform a soil test, go to the VCE Publication 452-129, “Soil Sampling for the Home Gardener,” VCE pub 452-129
The optimum time to prune fruit trees is just before bloom. Pruning allows the tree to direct nutrients to branches that will bear high quality fruit. The object is to remove dead, diseased or damaged wood. Also, remove shoots that are growing straight up or straight down as neither provides for good fruit development. Growth crisscrossing the center of the tree should be removed as well. A more open tree allows greater light penetration and air circulation, thereby increasing fruit quality and reduced disease and insect pressure. For additional information on growing and maintaining fruit trees in the home garden, see VCE Publication 426-841, “Tree Fruit in the Home Garden,” VCE pub 426-841
Bramble fruits such as raspberries and blackberries may be planted in mid to late March. Plant in moist, well-drained soil containing large amounts of humus or organic matter. For weed control, mulch around newly planted brambles with a hardwood or softwood mulch. For additional information on how to grow bramble fruits, see VCE Publication No. 426-840, “Small Fruits in the Home Garden.” VCE 426-840
Colorful Native Hardwoods for the Landscape
Planting trees native to Virginia offers real advantages to the homeowner who wants to enjoy long term success for the landscape. With a few exceptions noted below, natives are much more resistant to pests and diseases and more likely to thrive in central Virginia. Some offer spectacular displays of flowers, leaves or bark, while others provide shade.
Late winter is an ideal time to plant a tree before the sap begins to rise. Choose a healthy tree from a reputable nursery in burlap or a pot. Bare root trees should keep their roots wet until planted in late fall or winter.
Plant your tree correctly. Dig a hole twice as wide as the root system and deep enough to finish leveling the soil to the same point on the trunk as it was before planting. Remove the tree from the pot to place in the hole. A burlap wrapping will deteriorate, but remove any wire at least halfway down the ball. If the roots have twisted around the root ball, either tease them to spread out in the hole or make three or four cuts in the root ball to allow them to grow out. Add enough dirt to cover the roots, then water thoroughly to settle the soil. When the water has been absorbed, finish filling the hole to the old soil line on the trunk. Add mulch 2-3 inches deep and 2- 3 feet wide around the tree, but pull the mulch away from the trunk itself. Stake the tree for support if necessary.
Hint: If you have deer in your area, take precautions. Males will sometimes kill a small tree cleaning their antlers in the early fall. All deer will eat the new shoots when forage is scarce. Two to four feet of chicken wire wrapped a couple of inches from the trunk will protect it; or a four foot high fence of the same material in a four foot square will usually keep the varmints away until the tree is established.
Flowering Dogwood (Cornus florida) is Virginia’s state tree and remains the most popular native despite recent trouble with disease and borer damage. The Stellar® hybrids (crosses of C. florida and C. kousa) are more hardy and can take more sun, although they would not be considered true natives.
The beloved Virginia dogwood with its distinctive white bracts 2-4 inches wide is often tinged with red or purple and blooms close to the official start of spring. It complements mature long needle pines, oaks and maples in many yards. The leaves will be among the harbingers of fall as they turn a deep wine-red with an early frost and persist for weeks. Red, glossy fruit attracts birds.
Dogwood needs to be planted in the understory in order to benefit from the shade of larger trees. In deep shade, it can develop a single trunk, but with a little sun it often puts out low lateral branches making it a large shrub. Under good conditions, it grows to 30 feet. Avoid planting dogwoods in full sun. Poor or compacted soils will need amendments of compost or topsoil; and mulching the area under the branches will help insure moisture for the roots.
Eastern redbud (Cercis canadensis) is the other showoff in springtime with a multitude of small, pink-purple flowers ranged along the young branches. Its growth habit is less regular and more open than the dogwood, making it a candidate for a single specimen in your sunny yard. Throughout winter the long, brown seedpods hang from branches. Although redbuds may be abundant in the wild, they have not transplanted successfully for me, so buying from a good nursery is a better bet. For a full description of redbuds, see Pat Chadwick’s article in this issue.
Eastern Redbud
Fringe tree ( Chionanthus virginicus) Later in spring the delicate panicles of the fringe tree, also known as old man’s beard, will spread its blanket of ivory blossoms over the branches. Its modest size (12-20 ft.) and slower growth make it a good candidate for smaller yards. The deep green leaves turn gold in fall, and dark blue fruit attracts birds. This tree prefers sun to partial shade and moist, well-drained soil.
Serviceberry (Amelanchier arborea) requires similar soil conditions to the fringe tree, but may grow twice as tall, displaying a thick array of white flowers in clusters that are replaced by maroon-purple berries devoured by birds. Leaves will turn yellow, golden or red in the fall. Leaf-eating insects may do some damage.
River birch (Betula nigra) offers little in the way of spring flowers, but provides year round interest in the bark, which peels abundantly in irregular, paper-like layers that are alternately khaki, cinnamon and brown. Often found along stream banks, hence the name, where it’s used to prevent erosion, this tree can grow to 70 or 80 feet. The trunk often divides and the long twigs droop lazily toward the ground. Be warned that these switches fall abundantly throughout the year.
River birch
Sugar Maple (Acer saccharum) is hard to beat for red and yellow fall color. Although it prefers cool temperatures and loamy soils in higher elevations, it often does well for us lowlanders. It’s a large shade tree (70-100 feet) with seeds borne on the wind by means of little propellers beloved by children. Sapsuckers may ring the trunk looking for the sap used to make maple syrup (we make the syrup, not the birds).
Sweet gum (Liquidambar styraciflua) also offers color in fall with its star-shaped leaves: mostly deep red, as well as purple, orange and gold. Growing 60-90 feet tall in a pyramidal shape, its hardened sap was, in earlier times, chewed for gum. In order to plant it in your yard, you will want to buy a “fruitless” variety that will not litter those one-inch prickly “gumballs” that make walking difficult.
Sweet gum
For more information:
Common Native Trees of Virginia, Virginia Dept. of Forestry, 2007.
“Tree and Shrub Planting Guidelines,” Bonnie Lee Appleton and Susan French, http://www.pubs.ext.vt.edu/430/430-295/430-295.html
“Flowering Dogwood, Cornus florida,” Alex X. Niemiera, http://www.pubs.ext.vt.edu/3010/3010-1484/3010-1484.html
“24 Ways to Kill a Tree,” Bonnie Appleton, http://www.pubs.ext.vt.edu/430/430-210/430-210.html
“Dogwood Borer,” Eric Day, http://www.pubs.ext.vt.edu/2808/2808-1010/2808-1010_pdf.pdf
For these natives as well as other options: “Problem-free Trees for Virginia Landscapes,” Mary Ann Hansen, http://www.pubs.ext.vt.edu/450/450-237/450-237.html
“Selecting Landscape Plants: Flowering Trees,” Diane Relf and Bonnie Appleton, http://www.pubs.ext.vt.edu/426/426-611/426-611.html
The Ornamental Garden in March
It’s March and the ornamental garden is emerging from its long winter sleep. Crocuses, daffodils, hyacinths, and other spring flowers are emerging from winter dormancy. Forsythia, andromeda, pussy willows, camellias, hellebores and a host of other spring-blooming plants are at their peak this month. Garden centers and nurseries are open for business with a wide selection of cold-hardy annuals for sale. And you, the intrepid gardener, are anxious to start digging in the dirt.
But hold on a minute. Despite all these early signs of spring, the soil in March is generally too cold and wet to work in. Just walking on soggy soil compresses the soil aggregates and particles. The resulting compaction affects drainage and rain infiltration and prevents plant roots from penetrating very deeply. Soil compaction also reduces the amount of open pore spaces, which makes it difficult for plant roots to absorb oxygen and water. Here’s how to tell whether your soil is dry enough to work in: Dig up a small amount of soil and squeeze it in your hand. If the soil stays in a solid muddy ball and does not fall apart, it’s too wet to work in. If the soil crumbles through your fingers when you squeeze it, then it’s ready to be worked.
Once the soil is dry enough to walk on, clean up ornamental flower beds. Remove matted leaves, twigs, and other debris. Cut back dead stems and foliage from perennials that were left standing over the winter.
Remove any weeds that have overwintered in your flower beds. It’s important to tackle weeds early and stay on top of this task throughout the growing season.
Redefine flower bed edges as needed. A flat-edged spade is very useful for this task.
Top dress flower beds with one inch of compost. This acts as a soil conditioner, which improves the soil structure and adds nutrients and moisture-holding capacity.
Assess your emerging plantings and identify perennials that need to be divided. Many perennials benefit from being divided about every three–to–five years. As a general rule, divide spring–flowering plants after they bloom; divide summer–flowering plants in late summer or fall; and divide fall–blooming plants in the spring. And here’s another tip: Hostas may be divided just as they emerge in early spring. This minimizes damage to the leaves.
If it’s been a while since you’ve had your garden soil tested or if you’ve never had a soil test done before, consider having one done now to determine the pH and to see what nutrients, if any, are deficient. For information on soil testing, check out the Virginia Cooperative Extension’s (VCE) website, which is http://www.ext.vt.edu and view Publication No. 452-129, Soil Sampling for the Home Gardener.
Finish any pruning chores that you didn’t complete in January or February. This task should be completed before plants break dormancy. VCE Publication No. 430-462, A Guide to Successful Pruning, Shrub Pruning Calendar, (https://pubs.ext.vt.edu/430/430-462/430-462.html) provides information on when to prune. It will tell you, for example, that March is a good time to prune beautyberry, boxwood, clethra and roses, among others.
Cut back ornamental grasses and liriope before spring growth appears. If you wait too late to perform this task, you may damage newly emerging foliage.
Prune roses to improve the health and structure of the plant. Make sure your pruners are sharp and clean. Prune canes to an outward-pointing bud and make each cut at a 45° angle just slightly above the bud. Remove any weak or unattractive canes. Cut any damaged wood back about one inch into healthy wood. Cut any dead canes down to the ground level. If any branches rub together, choose the healthier of the two and remove the other one. If you are pruning a grafted rose, check for suckers below the graft union and remove them. Proper pruning facilitates better air circulation, also allows more sun into the middle of the plant, and results in a healthier, more attractive plant.
Now is a good time to plant bare root, dormant roses. Soak the bare-root rose in a bucket of water for at least eight or more hours to rehydrate the roots. Choose a sunny, well-drained location, dig the planting hole wide enough and deep enough to easily accommodate the roots and set the plant so that the graft union is at soil level. Space roses far enough apart to allow good air circulation.
Clean leaves and other debris out of aquatic gardens to help reduce algae growth when temperatures warm up. Tip: If amphibians live in your pond, be careful not to disturb them. If they have already laid their eggs, be very gentle as you work around the eggs to avoid harming them.
Humans aren’t the only creatures intrigued by the early spring landscape. Deer are keenly interested in it as well – as a source of food. If deer are a nuisance in your garden, apply repellents or other deterrents as soon as the plant foliage emerges from the soil. The idea is to condition the deer to view your emerging plantings as unpalatable. Generally, no one deterrent, short of a physical barrier, is enough to stop a hungry deer. See VCE Publication HORT-62NP, Deer: A Garden Pest (http://www.pubs.ext.vt.edu/HORT/HORT-62/HORT-62.html) for more information on how to deal with deer problems. Another good source of information is VCE’s Pest Management Guide: Home Grounds and Animals (http://www.pubs.ext.vt.edu/456/456-018/456-018.html).
If you plan to grow annuals, check seed packets for guidance on the merits of direct sowing versus starting seeds indoors. Tip: If you decide to start your seeds indoors, sow them in a fine, soilless growing medium. Place under cool-white fluorescent lights about fourteen to sixteen hours per day and position the lights about two inches from the top of the seedlings. Maintain daytime temperature at 70° to 75° F and 65° F at night. Keep the growing medium moist but not wet.
Spear into Spring with Asparagus
Several years ago, I was informed by my wife that we were going to plant asparagus. My response was: what are we going to do with asparagus? I was gently informed by my gourmet wife that asparagus was a very versatile vegetable, that it can be steamed, sautéed, roasted, grilled, stir-fried, featured in a salad or soup, or even eaten raw; in other words, the possibilities are endless. In addition, it is one of the earliest spring vegetables, and it would be nice to have something fresh from the garden in the spring. Naturally I concurred with my wife, and suggested that she order some seeds and we would plant them in the garden where we had planted corn the prior year.
But my wife’s response to my seed-purchasing proposal was “That dog isn’t going to hunt” — because asparagus is a perennial, and once planted, it can keep producing for 15 years or longer. Well, so much for that brilliant idea of crop rotation. I needed to find a permanent location for the asparagus. After thinking for a moment, I came up with the perfect location — a spot on the northwest corner of the lawn that was out of the way, and most importantly, it would cut out a little lawn-mowing. Perfect! Well, not exactly. When I proudly informed my wife of my proposed location, she got that look — you know the one — like when you go shopping and you are wondering if you left the oven on. I can still hear her words: “Incredible, under the oak tree … and where you got the mower stuck last spring…” plus a few other dangling modifiers that I didn’t care to catch. So on that high note, I figured I had better do a little research before offering any additional suggestions. Following is a summation of my remarkable asparagus horticulture journey.
The most critical decision a gardener must make, once he or she decides to grow asparagus, is site location, because, as I mentioned, asparagus is a perennial, so the site should be thought of as a permanent location. Like most vegetables, asparagus will not tolerate wet soggy soil. Select a site that receives full sun and that is well-drained or use a raised bed.
Okay, but how do I know if the location is too wet? Well, after a rainfall, if water stands in the spot selected for more than an hour, it’s probably too wet for asparagus.
The bed should be prepared as early as possible by amending the soil with organic matter such as manure and compost. A soil test should be performed, as asparagus does poorly in soil with a low pH (high acid); the Virginia Cooperative Extension recommends a pH range of 6.0-6.7. https://pubs.ext.vt.edu/426/426-401/426-401.html However, some researchers suggest an even less acidic, higher pH, because fungal diseases that contribute to asparagus decline — Fusarium crown and root rot — survive better in more acidic soil. Increasing the soil pH level to 7.0-7.5 reduces the survivability of Fusarium. For additional information on pH levels for asparagus, take a look at http://www.pubs.ext.vt.edu/AREC/AREC-66/5-specific-commodity-recom.pdf The higher pH level does not appear to affect the productivity level of asparagus, only the fungal diseases.
Good soil build-up is important with asparagus. We only get one chance — and that’s before planting — to adjust soil root-zone depth to 12-18 inches. If this opportunity is missed, it becomes very difficult to move nutrients deeper into the soil without disturbing and damaging the roots.
Asparagus may be planted 4-6 weeks before the final spring frost, which historically in our area is the last week in April.
Although it is possible to grow asparagus from seed, most home gardeners prefer to plant one-year old crowns because of the additional time and maintenance required to grow asparagus from seed. For additional information on how to grow asparagus, see VCE Publication No. 426-401, https://pubs.ext.vt.edu/426/426-401/426-401.html
For asparagus beginners, the second critical decision is what variety to select. There are two major categories to choose from:
1. open-pollination varieties, which include Mary Washington and Martha Washington, or
2. all-male hybrid varieties, such as Jersey Knight and Jersey King.
Asparagus is a dioecious plant, which is just a fancy way of saying that there are both boy plants and girl plants; thus, male and female flowers are produced on separate plants. The flowers on male plants are small, bell-shaped, whitish-green and more conspicuous than female flowers. Following pollination of the female flowers by bees, a round berry containing one to eight seeds is formed and turns red at maturity.
In the late 1800’s, Professor William J. Green, a horticulturist at the Ohio State Research Station, discovered that male asparagus plants are about 50% more productive than female plants. I’m not making this up! More information about Professor Green’s research and about early 1900’s growing techniques can be found at http://www.gutenberg.org/files/31643/31643-h/31643-h.htm.
One of the conclusions that Professor Green made was that the lower productivity of female plants is the result of energy allocated to seed production. The fruit produced by the female plant competes with the crown and roots for nutrients. Since asparagus is a perennial, the plant depends on the nutrients stored in the crown and root for next year’s spear production; therefore, the female plant is storing up less energy in the form of sugar and nutrients, resulting in lower yields than their male counterparts. For additional information about the advantages of male asparagus plants, see http://aesop.rutgers.edu/~asparagus/program/male.html
Being something of a history buff, I wanted to find out a little about when and how the male hybrid plants were developed. In the 1980’s Rutgers University began releasing what are called “supermale” hybrids developed by Dr Howard Ellison, a horticulturist at Rutgers University. Dr Ellison is regarded as the pioneer in the breeding of the supermale plant. A brief overview of Dr. Ellison’s work may be found at http://vegnet.osu.edu/sites/vegnet/files/imce/Asparagus trial.pdf
After reviewing the attributes of the hybrid male asparagus plants versus the open-pollinated plants, I elected to go with the all-male hybrid plants. A visit to the VCE web site at https://pubs.ext.vt.edu/426/426-480/426-480.html suggested two varieties for our area: Jersey Knight F1 and Jersey Giant. I selected Jersey Knight F1 to plant.
Next, I identified a dry, well-drained location, amended the soil with organic matter, and planted and covered the crowns. Here’s where patience comes in handy. I needed to wait until the second spring after planting to harvest any spears. The first harvest should be not more than 2 or 3 spears per plant. But patience paid off. Nowadays, I harvest young spears for a period of 4 to 8 weeks.
Is it “OAD” (one and done)? Well, not quite. Asparagus is a poor competitor with weeds; therefore, in order to have a successful asparagus bed, I needed to maintain the asparagus bed by keeping it as weed-free as possible. I accomplished this task by hand-weeding and very light cultivation with a hoe; I avoid the use of a tiller or digging deep to avoid damaging the crowns. Organic mulches such as “weed free” grass clippings, leaf mulch, wood chips, “clean” straw or compost can be applied up to 2-3 inches deep to suppress weeds. Weed-free grass clippings and clean straw? No, I elected to use leaf mulch mixed with wood chips. I recall being told by an elder Madison County gardener to use common rock salt as a weed control because asparagus, being deep-rooted, can tolerate some salt, but I elected not to follow this advice because salt can damage soil structure by creating a crust that impedes water infiltration. In twenty years or so, when it comes time to start another asparagus bed at a different location, what would I plant in the old location with its salty soil?
Asparagus plants are heavy feeders, meaning they require a lot of nutrients, so every 2-3 years I take a soil sample and send it off to the Virginia Tech soil lab to determine any nutrient deficiencies or pH adjustments that may be needed.
Now each spring when I go out to harvest those first asparagus spears, I think back on my amazing journey with asparagus. Sometimes I pause to imagine the reaction of our colonial ancestors when they walked out to the garden and found those first green spears after a long winter without fresh vegetables. No wonder asparagus was one of the first vegetables brought to this country by our forefathers.