HO-78 C O O P E R A T I V E E X T E N S I O N S E R V I C E U N I V E R S I T Y O F K E N T U C K Y • C O L L E G E O F A G R I C U L T U R E GROUND COVERS FOR KENTUCKY LANDSCAPES Lenore J. Nash, Mary L. Witt,William M. Fountain, Robert L. Geneve “Ground cover” is a term that describes a wide variety Color and texture offered by ground covers give the of plants useful for special planting situations. A common designer additional choices. There is a wide array of characteristic of all ground covers is uniform growth that foliage textures and colors, as well as seasonal flowers and covers the ground with enough density to compete well showy fruit. with weedy plants. Ground covers may function as traffic barriers Naturally-occurring ground covers are a delight, because they do not invite you to walk on them as turf although we may often miss the fact that they are indeed grasses do, yet they are low enough not to be a sight serving as ground covers. Think of mixed assortments of barrier. In this capacity, they give the added benefit of perennial flowers and ferns in a wooded area or snowberry keeping lawnmowers and string trimmers away from blanketing steep slopes along road cuts. valuable woody and herbaceous plants. Ground covers are valuable in special sites where turf grass will not thrive, where regular turf maintenance (mow- Soil ing) is a problem, or where a diversity of color and texture Ground covers grow in close proximity, so well- are desirable. Use of woody shrubs, vines, and herbaceous drained soil and soil with proper nutrient content are two perennials as ground covers has become increasingly popular important objectives to achieve before planting. After in residential and commercial landscapes and along high- deciding on your planting site, take a soil sample to your ways. They can be deciduous or evergreen, broadleaved or county Extension office to have it tested for pH and needle-leaved, three feet tall or ground huggers. Most of the fertility. Many county Extension offices have soil probes time, ground covers serve to refine gardens, to give that final that can be borrowed for taking soil samples. Otherwise, perfect look to an already well-planned landscape. push a spade seven inches into the soil and throw the soil This publication provides general cultural information aside. Take another 1-inch slice of soil from the back of about ground covers, lists of ground covers for specific the hole to its full depth. Remove all soil but the center 1- to sites, and individual plant descriptions. 2-inch-wide core. Place this core of soil in a clean bucket. Repeat the procedure in different spots within the planting Designing with Ground Covers site to get a representative sample of the whole site. Mix the Ground covers are well-suited for creating landscape composite sample well, and put it on some paper to dry for patterns. Because many ground covers are low and dense, several days. Then take it to your county Extension office for they can be used in broad, flowing curves, geometric- analysis. The cost of the soil test varies with the number of shaped patches, graceful sloping areas, special carpeting elements tested, but at a minimum phosphorous, potassium, patterns, or anything else that is appropriate in the overall and pH analyses should be requested. design. As a design element, ground covers work best as a unifying feature for garden beds. Individual trees and Soil Preparation shrubs in a landscape are tied together as a unified group Preparing the soil for planting is a must, and one by a common mat of ground cover. should never be satisfied to live with an unfavorable soil. Many contrasts and associations can be created with The extra effort taken before planting often determines ground covers. You can use ground covers: success or failure. • with lawn Step 1: Weeding. Remove all plants from the planting • with other ground covers area that will interfere with the growth of ground covers. • with trees, shrubs, and vines; and Hoeing will get rid of shallow-rooted weeds, but deep- • with annuals and perennials. rooted weeds, like dandelions, must be dug out by hand or AGRICULTURE • HOME ECONOMICS • 4-H • DEVELOPMENT 1 hoed very deeply to remove the whole root or rhizome. If Soil pH tilling is desirable, do it to a depth of six inches if pos- Soil acidity is measured as “pH.” Soil pH is an index of sible, incorporating organic matter at the same time. If the amount of acidity present; the pH scale ranges from 0 problematic weeds like bermudagrass are in the area to be to 14. At pH 7, soil is neutral. At pH levels below 7, soil is tilled, kill them first because tilling will help propagate acid, and at pH levels above 7, it is alkaline. Most nutri- them and guarantee infestation. ents required for plant growth are available to plants Sometimes it is appropriate to kill existing vegeta- within certain pH ranges. If the pH level is not correct for tion completely and plant directly into dead sod. The your plants, they may not be able to take advantage of the post-emergence systemic herbicide glyphosate nutrients in the soil. A soil pH between 5 and 7 is within ® (Roundup ) can be used for control of most annual and the range of adaptation for most ground covers. To raise perennial weeds. Be sure to follow label directions pH, lime is added; to lower pH, sulfur is added. For details exactly, and carefully avoid plants that are to remain in on changing soil pH, see University of Kentucky Coopera- the site while spraying glyphosate. If weeds or grasses tive Extension Service Publication ID-72, Principles of show signs of regrowth, spot spray with glyphosate as Home Landscape Fertilization. necessary for complete kill. If you prefer non-chemical means of getting rid of the Planting and Maintenance vegetation, cover the area with newspapers or black plastic for at least two weeks to smother the plants that are there. Planting Slopes It is appropriate to plant directly into dead sod in four When planting slopes, it is critical to keep the soil in instances: place until the plants are able to better control erosion. • if the existing soil structure is desirable (original Some methods of planting that help keep the soil in place topsoil, not compacted, good soil particle aggrega- include: tion, and channeling by earthworms) • digging planting pockets rather than complete tilling. • if the area is steeply sloping, • planting in staggered rows. Staggered plants do not • if minimum disturbance of shrub and tree roots is allow water to run off in a straight line. important, and • mulching the entire area once plants are in place. • if there is concern about soil moisture conservation. • using netting such as jute to hold the plants and Step 2: Adding amendments. “Good soil” means good mulch in place. Jute comes in 4 to 6 ft. wide rolls drainage, soil that has air available to roots. Roots do not that can be unrolled from the top of the hill and held develop unless oxygen and moisture are constantly in place with wire staples or coat hangers cut and available to them. This ideal situation is realized by bent into U-shaped fasteners. adding organic matter to the soil. Amend the soil in level or gently sloping sites with chunky organic matter (wood Mulch products, peat moss, animal manure). The primary reasons for applying a mulch at planting Ideally, organic matter should be added in the fall, left are soil and water conservation, weed control, moderation alone until spring to decompose, then tilled in to add of soil temperature extremes, and reducing the chance of humus to the soil. Fall or winter is also the time to add any lawn-mower damage to plants. In addition to these material to alter pH (see section on pH below) and benefits, organic mulches add organic matter (humus) to phosphorous and potassium fertilizer, if needed. the top layer of soil. Humus helps improve soil structure, Spade or till all amendments and fertilizers into the water retention, and oxygen diffusion. soil to a depth of about 9-12 inches, rake the soil smooth, Mulch applied at a depth of two to four inches at and water it. If low spots appear after watering, fill them planting must be reapplied to maintain that depth. The in before planting. frequency of application depends on the type of mulch used. Step 3: Digging the Soil. Dig or till the planting area if Types of Mulch the site is level or only slightly sloping. Try to incorporate Commonly used mulches are wood chips, conifer bark as much organic matter as possible while digging or products, cypress bark, and hardwood bark. Other types of tilling. Remove rocks, roots, buried construction debris, mulches are shredded leaves, stone, and pine needles. and any other foreign matter. Grade level or slightly Wood Chips. Wood chips are often readily available sloping sites with a rake to eliminate humps and fill in and free; however, they lack uniformity since they may hollows. come from different sources. Also, they tend to lose much On steep slopes, leave the soil surface as undisturbed of their decorative appearance with time, weathering to a as possible to minimize soil erosion. Erosion of the soil gray color.