Planting Groundcovers

The Right Season

The best time to buy and plant annual plants to create a patch of groundcover is in the spring when they are available as inexpensive, young seedlings. Petunias, impatiens, nasturtium, alyssum and others spread quickly when the weather warms to form a colorful mat that will last until frost. Spring is also the best time to buy and plant evergreen plants. Low-growing shrubby needled conifers such as rug type junipers or broadleaf azaleas establish quickly and begin to knit together during their first growing season. So do seedlings or potted clumps of ivy, pachysandra, liriope, vinca daylilies, ferns and other perennial plants.

The best time to buy and plant deciduous plants such as spring blooming bulbs or sweetspire, for example, is mid- to late fall. These are plants that lose their leaves, so at this time, only their roots are growing. In many regions areas they have a month or two to become established before the ground freezes hard. Their root systems will then be able to support renewed top growth and new leaves that come in the spring.

Planting Nursery Stock

Groundcover plants are available at the nursery or garden center in wooden flats, multiple market packs or individual containers. If you must delay planting, keep them out of the bright sun and well watered. Plant on an overcast day, or late afternoon on a sunny day, to protect new plants from direct sun while they recover from transplant shock.

Clear the planting area of weeds and debris. If you are replacing an area that was lawn, either remove the sod or spray the grass 2 weeks before planting with a non-persistent burndown herbicide such as glyphosate (RoundUpä) to kill it.
Dig up and turn over the soil down at least 12 inches with a shovel, or small tiller. Sprinkle a few handfuls of slow-acting granular fertilizer on the tilled soil, and rake it smooth.

Dig holes for each that are about the size of their containers, spaced so that they have room to spread to their mature size as indicated on the plant label.

Set each young plant in its hole so that its crown, the thick area where the root system and the stems meet, is just at the soil surface--no deeper. Fill in the hole with soil, firming it gently around plant stems. To plant rooted pieces, dig a trench in the loosened soil about 3 inches deep and lay the stems along its bottom, then cover their roots with soil.

Water transplants generously at planting time and regularly for a few weeks afterward to help the plants become established.

To keep the soil moist and discourage weeds during this time, spread some kind of organic material, such as chopped leaves, wood chips, bark chips, or pine needles on the soil between the new plants.

How Many Plants to Use?

If you plant them too far apart, plants intended for groundcover will take longer to fill in and cover their area. Weeds may become a problem during the delay. If you put the plants too closely together, they will fill in faster, but you may waste time and money on more plants than you need for the space. This chart indicates how much area 100 groundcover plants at various spacings takes up. This is useful for bulbs, annuals, perennials, and some of the smaller shrubs.

Figuring The Numbers
100 plants4 inches apart11 square feet
100 plants6 inches apart25 square feet
100 plants8 inches apart44 square feet
100 plants10 inches apart70 square feet
100 plants12 inches apart100 square feet
100 plants15 inches apart156 square feet
100 plants18 inches apart225 square feet
100 plants24 inches apart400 square feet

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