Do you have a sunny hillside or bank that’s hard to mow? Are you cutting grass in hard-to-reach areas and tight spots where you don’t need open lawn? Perhaps you should consider replacing grass with ground cover plants in these areas. We’ve written about perennial groundcovers in previous columns, however your situation might call for a woody (shrub) groundcover.
Woody groundcovers are shrubs that grow sideways instead of upwards, creating a dense mat that stops erosion and controls weeds once it’s established. If you take the trouble to install them properly and keep them weed-free until they fill in, horizontal shrubs can be the most maintenance-free way to deal with steep banks and other hard-to-mow situations. Let’s look at some of the best woody groundcovers, and how to install them so they pay for themselves.
For sunny areas, our favorite woody groundcover is prostrate juniper (juniperus horizontalis), sometimes called “carpet juniper”. Actually, the lowest-growing carpet junipers like “Wiltoni” and “Blue Pacific” aren’t the best for weed control. They let too much sun filter through, allowing weeds that are very hard to deal with in established groundcover. We prefer taller prostrate junipers like Andorra and Sargent, which grow over a foot thick and spread eight feet wide or more. These hardy evergreens love full sun, survive the worst drought and create a really dense shade that discourages weeds.
Cotoneaster is another woody plant that grows sideways. “Tom Thumb” is very low and slow-growing, but very dense. “Coral Beauty” grows faster and taller, averaging two feet high, and spreads rapidly, rooting into the soil wherever it touches the ground. It has attractive berries, and looks really good hanging over concrete retaining walls and other eyesores. Cotoneaster (pronounced coe-tony-aster) loses its tiny glossy leaves in winter, so it’s less effective as a weed barrier than juniper.
Another favorite spreading shrub is the fragrant sumac “Gro-Low”, which has more spectacular fall color than burning bush. We like to plant it around septic tank covers and other ugly utilities. Like cotoneaster, fragrant sumac will take hold anywhere it touches the ground, so one plant can eventually cover a very large area.
The challenge is keeping the are weed-free until the groundcover plants get established, which can take two or three years depending on spacing. It’s really important to plant them in good soil with fertilizer and peat moss mixed in. Ideally the whole area should be deep-tilled. The faster the plants grow the better for weed control. In the meantime you should mulch heavily each year; three or even four inches thick, and diligently pull any weeds before they go to seed.
Another way to install woody groundcovers is to use stone mulch with a weed barrier fabric underneath. This doesn’t work as well for plants that root in where they touch ground; plants with a central trunk like juniper will do better in a hole in plastic than plants that colonize, like cotoneaster and sumac. It’s even more important to prepare the soil before covering it with fabric and gravel, so plants can quickly develop a healthy root system.
Getting rid of weeds in any kind of groundcover is really hard. The key to success is making sure your plants thrive, and keeping the area weed free for the first few years. Heavy mulching (most plants prefer pine bark) will save you in the long run. If you do this right, woody groundcovers will save you 30 mowings each year for the rest of your life. That’s worth a serious investment, don’t you agree?
Steve Boehme is a landscape designer/installer specializing in landscape “makeovers.” “Let’s Grow” is published weekly; column archives are online at www.goodseedfarm.com. For more information call GoodSeed Farm Landscapes at (937) 587-7021.