Native Groundcovers

By - Marc Radell, PSU Montgomery County Master Gardener 

People are often surprised when I ask if they are looking for particular characteristics regarding height, bloom color/period, or leaf texture – perhaps because they think that groundcovers are always low and non-flowering.  I also get quizzical looks when I suggest interplanting several species, though most people warm to the idea after I explain the aesthetic and ecological benefits of variety.  So, now I’ve decided to offer a talk just on groundcovers native to the Piedmont physiographic province of Pennsylvania, home to Montgomery County, and here’s what I plan to say.

What is a groundcover?
Think of an example of a groundcover. Chances are that you did not picture the most common groundcover of all: turf grass. Why? Perhaps because most of the plants that we see in the groundcover section at nurseries or in catalogs are vines, such as common periwinkle or subshrubs like Japanese pachysandra. Once we realize that a groundcover can be any plant used to cover an area of ground, it opens up a much broader ranges of plants to use. But we still need the same characteristics in groundcovers that we find in turf grass: comparatively low maintenance, rapid and dense spread, and perennial duration. In fact, homeowners generally want groundcovers where they cannot grow or maintain lawns: excessively wet or dry areas, slopes, or deep shade. “I have a bare spot where nothing will grow …”

Planting Groundcovers
Follow the Master Gardener mantra and put the right plant in the right place by referring to the chart below to find a groundcover suitable for your light and soil moisture conditions. Better yet, choose a few different groundcovers so that you can have some textural and color variety and increase the biodiversity of your landscape. For instance, combine evergreen ferns with alumroot or foamflower for year-round interest with a burst of spring flowers. When spacing groundcovers, I plan for three years down the road so that I won’t have to divide them for a while. This usually means spacing them at about twice the recommended distance. To reduce the amount of weeding for the first year or two, I mulch the gaps and/or plant them with annuals.

Now for the fun part!
Here’s where I get to describe some of my favorite groundcovers and show you some pictures. (This will be the heart of my PowerPoint slideshow.) Mind you, I generally avoid the type of mass plantings associated with groundcovers, because I prefer a more natural, diverse look. Nonetheless, I have found these plants to be some of my most reliable spreaders.

For dry, sunny areas. Common yarrow, moss phlox, and threadleaf coreopsis all do very well in the flowerbed near my driveway, where it is hot and dry. There are many interesting cultivars of each species, so you’ll have a wide range of colors from which to choose. Yarrow is great for native pollinators; goldfinches love the seedheads of coreopsis; and moss phlox serves as living mulch. I’ve also heard reliable praise of wrinkleleaf goldenrod ‘Fireworks’ as well as green-and-gold.

For wet, sunny areas. I don’t have any wet, sunny areas on my property, but if I did, I’d plant golden ragwort and sensitive fern based upon the recommendations of other Master Gardeners. I’ve seen beautiful colonies of both in local parks and have wished that I had a suitable area at home.

For dry shade. For those tough areas, try Pennsylvania sedge, alumroot, white wood aster, lowbush blueberry, or American bittersweet. I have all of these growing in relatively dry shade and they do fine. The alumroot and bittersweet do not spread as vigorously as they do when they get more moisture, but nothing seems to stop white wood aster with its attractive, heart-shaped leaves. There are many amazing cultivars of alumroot these days, and the colored foliage is a great way to brighten shady areas. In addition to delicious edible fruit, lowbush blueberries offer brilliant Fall foliage and interesting bark. I’ve also heard great things about the performance of two evergreen Dryopteris ferns in these conditions: shield fern and wood fern.  I plan to try them under some spruce trees next year.

For moist to wet shade or part-shade. Moist shade is one of my favorite gardening areas, because it is conducive to so many beautiful native woodland species. Spring ephemerals thrive in this environment and many have showy flowers, including wakerobins, Virginia bluebell, and Celandine poppy. Because their foliage often fades once the trees leaf out, you cannot rely on them for groundcovers; but you’ll want to tuck some in with your groundcover anyway, much as non-native gardeners do with daffodils. As for the groundcovers themselves, you should try wild ginger, toothed woodfern, wild geranium, alumroot, Allegheny spurge, and foamflower. The heart-shaped leaves of wild ginger look beautiful and host the caterpillars of pipevine swallowtail butterflies. Some of the cultivars of foamflower are stunning, and I can’t praise wild geranium enough. The flowers of both species can be spectacular, and the lobed or palmate leaves are semi-evergreen.

When nothing else will grow there. Give Virginia creeper a try. This is a tough plant and vigorous spreader. Careful though: it not only creeps, but also climbs. Because it climbs by gripping, not twining, it can quickly take over any tree or structure it nears. The best way to control it is through pruning (a.k.a. mowing and hacking.) This may sound like a nuisance, but Virginia creeper does the job – beautifully. The scarlet fall foliage can be breathtaking, and you will see many birds feasting on its blue berries. Keep your eyes out for interesting caterpillars, too. Several butterflies and moths use Virginia creeper as their larval host plant.

Resources
To identify additional native groundcovers or to find more information about growing any given species, check out the USDA Plants Database , the Ladybird Johnson Wildflower Center, or my website (Marc Radell).

I highly recommend any and all of William Cullina’s excellent books on cultivating native plants, as published by Houghlin Mifflin.
Thanks for reading, and happy gardening!