Watering Groundcover Plants
When groundcovers are first planted they need regular watering--an inch of water a week from rain or from a watering can, soaker hose, or drip irrigation --until they become established. After that they need supplemental watering only during droughts and in late fall before the ground freezes. At these times, water deeply once a week.
If you have good soil with lots of organic matter added each year and if your transplants are well mulched, you will need to water them only when it has not rained for a week or two.
If you have poor soil with little organic content or if you choose not to use mulch while there is still bare soil between them, then you may have to water the plants every sunny day. Once they spread and cover the soil, they will need very little extra watering.
Sprinkle some granular, all-purpose slow-acting fertilizer on the soil at planting time to get groundcover transplants off to a good start. It will provide consistent, uniform nutrition over many weeks as they struggle to become established. If they are in soil rich in organic matter, they should be able to manage fine for the season with this one dose of fertilizer.
If your soil in the planted area is poor, which is often the case in places where groundcovers solve problems, then supplement the initial dose of slow-acting fertilizer. Spray plant foliage with very dilute general-purpose liquid fertilizer about 3 weeks after you‘ve planted the new plants. Mulch with some organic material that will improve the soil as it decomposes over the season until the plants fully knit together.
Mulching and Weed Control
A 2-to 4-inch layer of an attractive organic material like wood chips, chopped leaves, shredded bark or dried grass clippings spread on the bare soil around the new groundcover plants will discourage weeds. Peat moss is also good if it is mixed with other organic material to help make it more absorbent.
Mulch is essential when your plants are in newly disturbed soil. During cultivation weed seeds are raised to the soil surface into sunlight. Until the groundcover plants grow together to shade the soil, weed seeds will continue to sprout unless they are covered by mulch. Deal with the occasional weed promptly by pulling them or scratching the soil with a hoe to dislodge them. Tougher weeds may require spot treatment with a spritz of herbicide. Be sure not to let it fall on nearby plants.
Organic mulch reduces soil moisture loss through evaporation, cooling it as well. Best of all, as it gradually decomposes, it adds organic matter to the soil. Earthworms pull fragments of mulch down into their burrows deep in the soil, thereby adding vital nutrients and improving soil structure and drainage. After several years, falling leaves that settle in between the established plants will provide sufficient mulch and provide decomposing organic matter. For more information see the file on Using Mulch
Pruning and Grooming
One of the virtues of a patch of groundcover is its low-maintenance. It needs very little attention once the plants are established and cover all the bare soil. It may be necessary occasionally remove plants damaged by dog urine, or to trim stems that venture beyond the boundaries. Some groundcover plants benefit from a midseason trim that removes dead flowers and leggy stems. This also encourages repeat bloom in daylilies and others.
Shearing or mowing every 2 or 3 years keeps plantings of pachysandra, euonymus, vinca, English ivy and other perennials vigorous, neat and healthy. Use hand or power hedge clippers, hand grass shears, or a power lawn mower at its highest blade setting to cut at about 5 or 6 inches. Shearing encourages sparsely growing plants to fill in and revitalizes tired foliage. Some plants look best if their dried foliage is removed or cut back every spring. Ornamental grasses, liriope, ferns and daylilies are among these.