Tidewater Gardening - October 2006

Ground Covers and Kale

by

K. Marc Teffeau

     After the recent passage of tropical storm Ernesto I found myself, like many other folks, out in the yard cleaning up leaf and twig debris from the strong winds and the rainfall. In particular, I have a hybrid Chinquapin Oak that dominates the right side of the front yard along the street. The majority of leaf debris came from that one tree. The tree was in the yard as a sapling when we moved in 27 years ago, and, in hindsight, being the trashy tree that it is, I should have removed it. But being new homeowners, having no money for landscaping and with son #1 on the way, I left it in place.
      Besides being trashy, always dropping dead branches and leaves, this tree casts a heavy shade and sucks up all the moisture around it. I tried to plant a few hostas at the base to give some color but the poor plants have always struggled. The turf under the tree is practically non-existent, a type of wild red fescue, and some shade-tolerant weeds. So what to do with this area?
      I started my search for a possible ground cover to put under and around the tree. I wanted something that would tolerate the shady and dry conditions. I didn’t want English ivy, partly because it is so common and would tend to become invasive once it got established.
      Liriope, sometimes called lilyturf, was another alternative. Lilyturf is an evergreen groundcover that multiplies rapidly and requires very little care.
      There are two major species of Liriope grown in our area: big blue lilyturf (Liriope muscari) and creeping lilyturf (L. spicata). These two evergreen lilyturf are favorite landscaping plants. Both plants form mounds of grass-like foliage. Usually the foliage is dark green, but in some varieties it is variegated.
      There are many cultivars available. They differ in leaf color, size and flower color. I already had lilyturf in one part of the landscape, however, so I wanted something else.
      A very interesting ground cover that I was not familiar with came to my attention from one of our grower members of ANLA. Known as Golden dead nettle, Lamiastrum, Variegated yellow archangel, and Yellow archangel, this long-lived ground cover makes a clump about 12 inches in diameter and gets about 12 inches tall. Lamiastrum galeobdolon, its botanical name, is unique in that it is covered for weeks in brilliant canary yellow flowers and its silvery variegated foliage illuminates the shadiest of areas.
      Lamiastrum is originally from Europe and is found widespread there. It is a member of the “Mint” family. As a mint you might expect this plant to be invasive, but this is not the case. It’s a clump grower rather than a runner and is very well behaved.
      A cultivar of Lamiastrum galeobdolon that is common in the nursery trade is “Herman’s Pride.” This spreading form trails on the ground with long stems which root as they come in contact with the soil. It can reach 9 to 15 inches tall and spread 18 to 24 inches easily in a short period of time. The evergreen leaves are opposite, medium green, 1 to 3 inches long, toothed on the edges and soft on both sides. They have silver marks and are aromatic when crushed. Flowering occurs in late spring to early summer, and flowers are brilliant yellow, ½ to ¾ inches long and are borne in whorls of 5 to 15 flowers. The fruit is non-ornamental.
Yellow archangel performs best in well-drained, fertile and acidic soils. In these conditions, the growth is fast. This species tolerates a wide range of soil conditions, and many gardeners plant it in fertile sandy soils to slow the growth.
      Yellow archangel does well in moderate shade but full sun is tolerated. References differ as to drought tolerance with some recommending an occasional watering during the summer if they are in sunny locations. It is winter hardy from Zones 7 to 9. Based upon the description of this ground cover, I might have found a solution to my problem. Will plant some this fall and see how it does next year!
      Fall color is here. The mums and pansies have arrived at the garden centers encouraging the gardener to add some color to their fall landscape. Besides mums and pansies, flowering cabbage and kale offer the consumer a plant which is both colorful and long-lasting in the landscape. While many of our flowering plants, including garden mums, lose their flowers and/or color after several frosts, flowering cabbage and kale will intensify in color and may, if we have a fairly mild winter, last until next Spring.
      Thanks to the plant breeders, many cultivars of Brassica oleracea, or flowering cabbage and kale, have good growth habits and strong foliar coloration. The “flower” or ornamental cabbage and kale consists of the central leaves of the plant. These leaves will lose Chlorophyll after several days of night temperatures below 50 degrees to reveal to coloration which ranges from white to pink to red. It will take 2 to 4 weeks to develop intense coloration from the start of cool night temperatures.
      Flowering cabbage and kale are divided into groups based on the shape of the leaf. Cultivars with smooth leaf margins constitute the flowering cabbage group, while those with divided or “fringed” leaf margins are considered flowering kale. Within the kale group there are two types: the most common are the “fringed leaf cultivars: which have finely ruffled leaf margins. A smaller number are called “feather leaved cultivars” and have leaves that are finely serrated and deeply notched.
      Cultivar selection will depend on growth habit and coloration. The Chidori series, with its fringed ruffled leaves and intense colors, have become the most popular. The Peacock and Sparrow series also come recommended as some of the prettiest. If your favorites are round-leaf types, then try the Dynasty series.
      Within each series there are normally a white, pink and red cultivar. These plants are very showy, and come in a variety of colors, ranging from white to pinks, purples or reds. The ornamental cabbages and kales look much the same as their edible cousins, but the ruffled foliage is much fancier and more colorful.
      Ornamental cabbages and kales do not tolerate summer heat, but are extremely cold-tolerant. They can survive winter temperatures as low as 5 degrees if they are gradually acclimatized. While a sudden cold snap can be deadly, light and moderate frosts will intensify the brilliant coloring of these plants. In fact, the colorful pigmentations which these plants are known for, do not appear until after prolonged cool weather and several frosts.
      When purchasing ornamental cabbage or kale, look for a plant with a short rosette-type stem. Generally, if these plants were allowed to become root bound in their pots, they will not get much larger after they are planted, so it may pay to but the biggest plants you can find, even though they may cost more.
      They may be grown indoors in a large pot, however the length of time they will last in the home will vary depending on the temperature, A brightly lit, cool room is the best location.
      If you didn’t plant them in August or early September there is still time to get them in. Watch out for cabbage loopers, which bore unsightly holes throughout the plant. The first or second hard frost will do these loopers in.
      Ornamental cabbage and kale should be planted in a sunny location in a moderately moist, well drained, rich soil. Prepare the soil by incorporating 3 to 4 inches of organic matter and 2 pounds of a slow-release, 12-6-6- fertilizer per 100 square feet of bed space. Set the transplant to a depth just slightly below the bottom set of leaves. The plants will reach 6 to 12 inches in height, and you will want to space them 12 to 18 inches apart.
      The fall season has been super for planting and now would be a good time to work on your beds. Be sure to add a good layer of mulch after planting to help stabilize soil temperatures and conserve moisture. Flowering kale and cabbage excel with beds of brightly colored pansies, violas, panolas and snapdragons. I am partial to the purple types grown with yellow pansies. Flowering kale and cabbage are not eaten, but the leaves do make very decorative garnishes for holiday feasts.
      Happy Gardening!!!