Low-growing ground cover plants benefit the landscape in a number of ways. They often thrive in areas unsuitable for most annuals or perennials, and most tolerate full sun or full shade, drought, poor soil and rocky terrain. Planted on an incline, they serve to prevent erosion; planted under trees, they protect tree roots from lawnmowers. Ground covers come in a wide selection of cultivars offering colorful blooms, which add beauty and interest. Although they need little maintenance, ground cover plants require trimming to stay healthy and manageable.
The goals of trimming ground cover plants are to remove branches that are damaged, diseased, untidy or growing in undesirable areas. For some types of ground cover, trimming also thins and rejuvenates plants, resulting in new growth or a second round of blossoms.
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Trim Based on Plant Type
Trimming ground cover falls under two categories: hand pruning or mowing with a lawn mower. The choice of whether to prune or mow depends on the plants involved.
Herbaceous and vigorous growers, having nonfibrous stems, can be mowed. It's easy to bag their stems and branches for composting or disposal. If possible, begin mowing when the plants are young and newly established. They recover from mowing in one to two months.
Plants with thick woody stems can jam or break a mower so hand pruning is preferred over mowing. It's difficult to bag their stems and branches so they may require bundling for disposal. These varieties tend to grow slowly, taking up to four months to recover from trimming.
Time to Trim
Spring-flowering cultivars need pruning or mowing after they finish blooming in early to mid-summer. Do not prune or mow in late summer or fall because subsequent new growth can suffer frost damage. If plants recover slowly, weeds often infiltrate openings in the ground cover. Summer and fall-flowering cultivars require mowing in spring at the first appearance of new growth.
Tools and Techniques
- Lawn mower. The mower will shear plants off across the top, leaving them all the same height. Set the lawnmower to the highest setting to ensure the ground cover is not cut too short. In lieu of a mower, a string trimmer will shear the tops of plants nicely. A string trimmer can also edge the outer perimeter of the area where the ground cover is planted.
- Hand Pruners. Bypass pruners,
lopping shears and hedge trimmers are
all very useful when hand pruning. Bypass pruners function like scissors with
blades that overlap. Lopping shears feature long handles and cut through branches
up to 1 3/4 inches in diameter. Hedge trimmers allow gardeners to cut more
than one stem at a time.
- Plan each cut carefully and proceed in order of pruning importance. Start by removing any damaged or diseased stems and branches. Cut back to a healthy section on the stem or branch. Next, make cuts for training purposes, removing any wayward branches growing in an undesirable direction. Finally, thin out any ground cover with a solid canopy. Cut one branch out of every three branches. Thinning allows light and air to circulate among the plants and helps ward off pests and diseases.
Never remove more than one-third of the plant at one time. Ground cover needs to be no shorter than 4 to 6 inches to stay healthy and recover.
Only purchase quality tools and take time to properly maintain them. Use a file or whetstone to sharpen blades on hand pruners and lopping shears. Lawn mower blades also need sharpening and balancing each year for best performance. Sterilize pruners, shears and mower blades by dipping the blades in 70 percent rubbing alcohol for 30 seconds. Do not rinse; instead, let them air dry.
Take steps to protect yourself while using hand-held tools, lawn mowers or string trimmers. Wear protective clothing including a long-sleeve shirt, pants, socks, shoes, gloves and safety glasses. If possible, have a mobile phone in a pocket to call for help if necessary.