Tidewater Gardening - April 2010


Winter Storm Cleanup
K. Marc Teffeau

As the February snows receded, the extent of damage done to trees and shrubs in the landscape from the record snowfall continues to be manifested. Some of the damage, broken and severed branches for example, should be cleaned up as soon as possible. Unfortunately, for narrow and broad-leafed evergreens, the plants will not re-grow damaged branches and fill in the exposed areas. And, as a usual reminder, when cutting out the damaged branches, especially on trees, do not apply black tree paint to the cuts. This material will inhibit the healing process and cause additional decay.
I have noticed that a lot of boxwoods took some pretty serious hits from the storms. With boxwoods, some of the damage resulting from the heavy snows is very apparent. However, some of the stem and bark damage resulting from the heavy snows will not manifest itself until later on in the summer when individual branches or sections of branches will yellow up. This results from bark splitting down inside the plant from the weight of the snow. To the untrained eye, the bark on the branches may seem intact. Closer examination will reveal that while the bark is still in place, it has actually separated from the underlying branch. Your only recourse if this occurs is to prune out the dead branch. Boxwoods are able to regenerate growth on exposed branches, so the plant may fill back out over time.
The Perennial Plant Association has selected an Eastern North American native perennial, Baptista australis, blue false indigo, as their 2010 Perennial Plant of the Year. According to the PPA, blue false indigo grows three to four feet tall and three to four feet wide in an upright habit. Their growing range is from Zone 3 to 9 and it is considered one of the most adaptable native species. Its violet-blue, lupine-like flowers extend well above the foliage and show in the spring for three to four weeks.
Blue false indigo has a number of uses in the landscape including in flower borders where it can be planted as a specimen or in small groups. For more information about blue false indigos go to www.perennialplant.org.
The daffodils did not seem to suffer much damage from the February storms. Fortunately, in most landscapes their foliage had not started to emerge. Observe your daffodil and other spring bulbs while in bloom this spring to be sure they have not been shaded by the new growth of other tree or shrub plantings. If they have, you may need to move your bulbs to a new, sunny location or prune back the other plantings. Label the clumps of daffodils that are too crowded, as overcrowding inhibits blooming. Dig up and separate in July.
Cut flower stalks back to the ground on daffodils, hyacinths and other spring flowering bulbs as the flowers fade. Do not cut the foliage until it dies naturally. The leaves are necessary to produce strong bulbs capable of reflowering. To keep the planting going you can fertilize bulbs upon emergence of foliage with a 10-10-10 commercial or organic fertilizer using a rate of 1 to 3 pounds per 100 square feet. Repeat the application after the bulbs have bloomed.
If the warm weather continues we might be looking at planting annuals in the landscape a week or two earlier than normal. When purchasing bedding annuals this spring choose properly grown plants with good color. Buy plants with well developed root systems that are vigorous, but not too large for their pots. Also, when you are out shopping for annual flowers for your garden, look for plants with lots of unopened buds. Plants that bloom in the pack are often root bound and can be set back for several weeks after being transplanted. Plants not yet in bloom will actually bloom sooner, be better established and grow faster. Be prepared to cover them overnight, however, if a frost warning occurs.
April is the perfect month to plant pansies in the landscape. A number of newer varieties have heat tolerance bred into them so they last longer in the landscape, going through June. You can brighten up your front door with pots of transplanted pansies or place them in outdoor beds as soon as the soil can be worked. Purchase large plants that will give a good show before hot weather arrives.
In April, chrysanthemums pop up in the flowerbed. Lift, divide and replant them as soon as new shoots appear. Each rooted shoot or clump will develop into a fine plant for late summer bloom. Pinch out the top when the plants are about 4 inches high to thicken the plant. You can also take chrysanthemum cuttings now through mid-June for flowers during fall and winter in the greenhouse.
Besides chrysanthemums, many popular perennials can be divided now including phlox, fall asters, Shasta daisies, baby’s breath and liriope. Set up a plant exchange with friends and neighbors to share the excess. Planted now, Sedum spectabile and Hosta tardifolia or H. plantaginea will brighten your flowerbed in the fall with flowers. Aster novae-angilae, which is a blue aster, or the red chrysanthemum cultivar ‘Minn Ruby,’ are also late blooming.
Now is also the time to do some planning and planting of perennial flowerbeds. One way to increase the apparent length of your flower borders when seen from inside is to place the majority of the warm- and hot-colored perennial plants (yellows, oranges and reds) nearest the house. Concentrate the blues, which have a tendency to appear more distant, in the second half of the garden. Along with the blues, include some pink and mauve flowers. Plants with silver foliage can be used to provide a unifying ground color throughout.
The actual dimensions of the borders and the paths separating them can help increase the illusion of distance. In a 20-foot-long border, make the planting about 1½ feet narrower and the path about 1 foot narrower at the end away from the house.
If you would like to attract hummingbirds to the flower border this year, plant red or orange flowers. Monarda (bee balm) is a good perennial to provide nectar for these small birds. April is also a good time to scatter annual poppy seeds in flower borders. The fine seeds need no covering. The plants grow rapidly and provide colorful flowers in early summer.
Be sure to make a plot layout of your flower borders. This is an essential, but easily neglected chore. With an accurate plot plan, you will know where to locate the spring flowering bulbs you plant next fall. Also, it will make your spring and summer gardening easier. You will be able to correctly identify the plants in your border and plan for continuous blooming by setting young annuals between bulbs and early flowering perennials after their blooms have faded.
Late April is a good time to plant dahlia tubers in the flowerbed. Stake them when you plant them to avoid injury to the tubers later. If you dug up and stored dahlia tubers over this winter, one easy way to determine if they have survived storage is to sprout them indoors in a warm lit spot.
Fill the bare spots in the flowerbed with moss roses, also known as Portulaca, and feed regularly to encourage blooms into the summer.
Besides planting annual and perennial flowers to attract hummingbirds, think about adding some woody plants to the yard to provide nectar for our smallest native birds. Some common trees visited by hummingbirds are buckeye, horse chestnut, catalpa, apple, crabapple, hawthorn, silk tree, redbud and tulip poplar. Shrubs include azalea, beauty bush, coralberry, honeysuckle, lilac, New Jersey tea and red weigelia.
If you receive a hydrangea as a gift plant you can transplant it into the garden after its flowers fade. When the weather warms, plant it in well-drained soil in full sun to partial shade. Don’t be surprised if the next year’s flowers are a different color than the first year. Blue or pink hydrangea color is dependent on the pH of the soil. Alkaline soil produces pink flowers; acidic soil produces blue flowers. White hydrangeas are not affected by soil pH.
Happy Gardening!!