Gardening is as contagious as the common cold. You begin breaking ground with the firm conviction of making a garden only so big. But soon one favored plant makes way for another shared one, innocently named a “pass along.” This simply means a plant that became so rambunctious in its previous owner’s garden that it needed to be passed along to a new home.
Now you have a thriving garden that grows so well you have no time to thrive yourself. Soon you need to take a serious look at ways to lessen the burden and care.
Mulch is often recommended as a solution to slow the spread of that flourishing garden. So you now have added yet another job, mulch application, to your gardening chores. Mulch has its advantages as it helps to keep the roots cool in warm weather and to retain moisture; however there is another good solution, ground cover.
Ground cover is defined as non-woody, herbaceous plants and “any of a variety of low-growing or trailing plants used to cover the ground in areas where grass is difficult to grow, as in dense shade or steep slopes.” In the agriculture industry, clover and alfalfa are used specifically to prevent erosion. Clover is a preferred nitrogen “setter” (generating nitrogen, a costly fertilizer) for future crops.
Ground cover is used by highway departments to prevent erosion on the sides of roads. Rapid-growth ground cover can have some major drawbacks. Kudzu, Pueraria lobate, also known as “mile-a-minute vine,” is a prime example. Imported from China, it was first introduced at the Centennial Exposition in Philadelphia in 1876 as an ornamental plant. During the Great Depression, it was imported to be used for erosion control. Imported plants come into countries without the benefit of the controlling insects of their native countries. As evidenced by roadsides in the South, kudzu quickly outgrew its intended purposes and space. Although kudzu has medicinal and nutritional benefits, its invasive qualities far outweigh its advantages. With a root that can grow to the size of a human and its ability to grow 60 feet in a single growing season, it quickly swallows up forests, vacant houses and surrounding vegetation.
Another common ground cover used by highway departments is crown vetch, a member of the Paplionaceae family. It has fine branches that can expand to six feet in diameter and spring flowers of white, pink and purple. Because of its rapid growth, this too can become invasive and needs to be carefully controlled. The Virginia Invasive Plant Species list is helpful in determining plants that quickly outgrow their boundaries.
Ground Cover for Our Gardens
Since most gardens need to be established with the use of ground cover in mind, there are abundant varieties available for every application. As with all plants, ground covers need to be evaluated and placed where they like to grow. They can be extremely useful, attractive and inviting when used in the right place.
Some varieties can withstand occasional foot traffic and can be used between pavers or on a path. Dwarf creeping wire vine, Muehlenbeckia axilaris, grows in plant hardiness zones 6-10. It typically grows from 1-2 inches tall and 8-12 inches wide. It prefers full sun (4-6 hours a day) to part shade and will tolerate heavy clay soil, but needs it to be well drained. White star creeper, Pratia angulate, has the same qualities as wire vine, and blooms with small white flowers in the spring. Creeping thyme, Thymus pulegioides, grows in zones 5-9 and has evergreen foliage which emits a delightful aroma when tread upon. Ajuga reptans and dwarf mondo grass both tolerate shade.
Sedums, which tolerate little to no foot traffic, feature foliage which can range from bright green to gold. Some even have red-tinged leaves. Sedums tend to be more drought tolerant than many plants. They tolerate light shade to full sun.
Some of the most reliable ground covers are not rare or unusual, but tried and true. Creeping phlox, Phlox subulata, will thrive in full sun to part shade and flourish in a variety of tough soil conditions. It spreads into a colorful, nearly carefree, spring carpet of pastel hues. Hens-and-chicks, Sempervivum tectorum, is an old-fashioned favorite. It’s a terrific ground cover for tight spaces and is a beautifully-textured focal point in a sunny garden. Pachysandra terminalis is a glossy green shade lover that tolerates the most unfriendly conditions, including poor soil.
Keep in mind plants need to be fully established, planted and watered every week when not receiving at least an inch of rain before they exhibit drought resistance. In the South, we are used to hot summers and need plants that can tolerate heat. Observe the exposure when viewing a garden and save yourself some trouble by knowing the needs of your plants.
Think Outside of the Box
Ground covers need not be small and vine-like. Consider large-leaved groupings around the base of small trees. Bergenia, with its large deep-green leaves, makes a wonderful grouping at the base of a small tree. Hosta in masses at the edges of a garden makes a wonderful statement. Also known as “deer candy”, hosta needs shelter from these predators. A fenced-in yard or a barrier around the perimeter of the planting serves as a useful deterrent to hungry deer.
For a windy bank on the river or seaside, Rugosa rose is a delightful ground cover. Its gnarly branches with sweet flowers decorate the area all summer long. Large rose hips (the apple-like seed pod, rich in vitamin C) follow the blooms. They can be used to brighten up your holiday greens, but remember to wear gloves because they are thorny. This plant tolerates salt spray and does a great job holding the soil on banks.
Native plants such as golden groundsel, also known as ragwort Pakera aurea, with its bright yellow flowers prefer part to full sun. Partridge berry Mitchella repens is a deep rich green with red berries and likes full to partial shade. Both make colorful interesting ground covers. The advantage to using natives is that they adapt well to the soil conditions and are resistant to animal foraging. For more information, consult napsva.org.
Ground covers are defined as herbaceous plants (those with non-woody stems), but they can also be small spreading shrubs. Juniper varieties fill that bill well with the Pacific or blue carpet varieties. Small groupings of dwarf hollies, or dwarf or miniature boxwoods, also do a great job of “anchoring” an expanse of garden and lessening the need for weed control and mulch.
Planting Ground Cover
Once you have established the exposure and soil you are going to plant, you need to measure the area. Research the growth of the variety you have chosen according to its needs. For the spacing of plants that need a six-inch space to grow, 48 plants will cover a ten-square foot area. For those needing 24 inches of growth space, 48 plants will cover 165-square-feet.
The soil needs to be prepared as you would for any other garden area. Soil testing is recommended every two years. A soil test kit can be found at a local garden center or your extension office.
Carefully examine the soil you are preparing. See if it is compacted from foot traffic or sandy and loose. Compost can work its magic by breaking up clay soil and aiding in its water retention. If you do not have a compost pile and have no woods to dig in to obtain it naturally, simply add peat moss and work it well into the soil.
When planting a steep slope where erosion can occur, place the plants in staggered rows. Flatten out an area to form a terrace with a small low spot to catch the water. They need to be planted with the crowns slightly higher than the ground to prevent rotting when watering.
The soil needs to be watered following planting and then every few days until established (when new growth shows). Continue to water new plants weekly when they do not receive an inch of rain for the first year. Do not forget to water on those occasional warm days in the winter.
The Continual Gift of Ground Cover
Once established, ground cover keeps giving. As it continues to grow, it expands. Stray plants can be plucked and placed where other ground cover is needed. Evaluating this spreading habit is important not only to take advantage of this trait, but to confine its growth to your space of choice. Some varieties of ground cover, and mint is one, need to be placed in confined areas. Vinca, mint, sedums and many others can expand and become somewhat invasive. Plant them in pots or areas controlled with some form of confinement such as brick borders, steel edging or pathways. Do not be afraid to allow the ground cover to spread to soften the edges of your garden and pathways for a beautiful effect.
Planting our gardens with ground covers requires some effort to establish them but the end result is less weeding and more gardening enjoyment. So begin to plan for those warm days of garden enjoyment. Watch your plants grow and lessen the time you spend weeding, with the help of ground cover.