How to Select Ground Covers
Turfgrass is the most common ground cover in the mountains. But lawns are a lot of work. Alternatives to turfgrass exist that are much easier to grow and maintain, and can prevent erosion where grass will not grow or where mowing is difficult. These ground covers can also be an important element in your landscape design.
Here are some considerations for selecting ground covers.
Look at the planting site. Is it sunny or shaded? Is the soil moist and rich or dry and rocky? Is the area reasonably flat or severely sloped? How much foot traffic does the site get? (Remember that you will be walking in that area each time you weed.)
By definition ground covers are invasive to some extent, or they wouldn’t be useful. Check with local nurseries and other gardeners before choosing. Some plants may be perfect for the mountains even though they are uncontrollable in warmer climates. Consider the effects on nearby plantings or structures if the ground cover spreads outside its assigned area.
Periwinkle (Vinca minor), also called “myrtle”, has lavender blue flowers in spring above evergreen foliage. Myrtle grows at a moderate rate and is good for large naturalized areas. Plant in part sun to full shade, 6 to 12 inches apart. Myrtle does not like foot traffic: I planted it on a steep slope, and many stems get broken each year while weeding.
English Ivy (Hedera Helix) grows in a wide range of soils. It prefers full or partial shade, but will grow in full sun. English Ivy has glossy evergreen leaves that form a dense mat of foliage 4 to 6 inches high, and attaches to structures or trees via aerial roots. Inconspicuous flowers appear in spring. English Ivy will take occasional foot traffic. It has a moderate to fast growth rate; plant 12 to 24 inches apart.
Bugleweed (Ajuga reptans) has bronze evergreen foliage only a couple of inches tall, with 6 inch flower spikes in spring. Some Ajuga varieties are quite aggressive, while others can be easily contained. Moderate foot traffic is okay. Bugleweed will grow in shade, but requires sunlight for the best foliage color. Plant 12 inches apart.
Maiden Grass (Miscanthus sinensis) is a series of grasses from 6 inches to 10 feet tall and wide, with colored or variegated leaves and various flower colors. They are useful for growing on slopes in sun or part shade, and are relatively disease and pest free. I planted Maiden Grass ‘Adagio’ on a hillside where grass had trouble growing. The only maintenance is cutting it down to a foot high in spring.
Other ground covers I’ve grown successfully include Pachysandra, Lamium, Honeysuckle vine, Boston ivy, Snow-in-Summer, prostrate junipers, Sweet Woodruff, and creeping thyme.
Your only chance to improve the soil is prior to planting; add organic matter and work it in. Get a soil test to see if pH adjustments are necessary. Kill any existing vegetation with a non-selective herbicide like glyphosate (RoundUp®, other brands) or cover the area with black plastic or several thicknesses of newspaper for a couple of months.
Spacing depends on the specific plant and how quickly you want to completely cover the area. For every 100 square feet (a 10 foot by 10 foot area) you’ll need 100 plants spaced 12 inches apart; 25 plants spaced 24 inches apart; or 400 plants spaced 6 inches apart.
Weeds may be a problem until the ground cover has filled in the area and shaded the soil. Adding mulch at planting time will help. A pre-emergent herbicide (like Preen® or Surflan®) can reduce weeding significantly.
Unless the soil test shows a deficiency, don’t fertilize until the plants are established. In subsequent years fertilize with a balanced fertilizer (like 10-10-10). Immediately wash any granular fertilizer off the plants to avoid burning the foliage.
Prune any time until mid-summer to remove dead limbs or to keep growth in check.
Be sure to read and follow the directions for any garden chemical you use.
‘Ground Covers for North Carolina’ lists these and more than 50 other plants. Download a copy at http://www.ces.ncsu.edu/depts/hort/consumer/quickref/ground%20cover/groundcover.html.
Jim Janke is an Extension Master Gardener Volunteer in Haywood County. For more information call the Haywood County Extension Center at 828-456-3575. © 2012 NC State University.