For newly planted groundcover beds, during the first spring and summer after installation, fertilize every month with a liquid spray such as Miracle Gro. Follow the label instructions for mixing.
After the first year, and each year thereafter, fertilize as follows: Every May apply a fertilizer with a formulation like 22-11-11 to all groundcover beds at a rate of 2 to 3 pounds of actual nitrogen per 1,000 square feet. Do not allow fertilizer to fall onto turf areas. Take care to “water in” the fertilizer immediately after application, and to wash all particles from leaf surfaces.
All types of groundcover need to be watered immediately after planting, as do all other landscape plantings. (Water thoroughly to the depth of the plant roots.) During the first 3 to 4 weeks after planting rooted groundcover cuttings, light, daily irrigation is beneficial. This initial period is the time when the roots will take to the new soil, and under-watering can kill the young cuttings, but over-watering can rot them or bring on disease. After the groundcover cuttings have become established, average rainfall should be sufficient. However, during drought periods, additional weekly waterings may be necessary.
Pruning and Thinning
Normally, very little pruning is necessary in the maintenance of groundcover beds. Remove un-wanted growth from sidewalk edges and around adjacent plants as needed. Pruning and selective trimming of tall plants should be done early in spring. Periwinkle, pachysandra, and purpleleaf wintercreeper can be most easily top-trimmed with a good sharp mower. As often as needed, use a mower or trimmers to cut groundcover to a uniform height. If the planting gets too thick, it can be “chopped” with a verti-cutter and raked out. Daylilies respond well to this, too.
A 2-inch continuous bed of mulch is necessary in all groundcover areas for the first one and one-half years. This will help to keep weeds and grasses out of the beds and allow the groundcover to fill in thickly and uniformly. All groundcover areas, except ivy, need to be cleaned out in late autumn if trees have dropped leaves into the beds, so the leaves do not smother and mat-down the groundcover over winter. Leaving fallen leaves in an ivy bed will protect the plants during a harsh winter. Remove these leaves in the spring.