Sunny flower bed with lawn.
Sunny flower garden locations are often filled splashes of brightly colored perennial flowers that may grow several feet tall. However, ground covers are an important component of any landscape and are more common than you might think. Your lawn is comprised of ground cover plants, typically Kentucky bluegrass, some other type of cool or warm-season grass, white clover or other low-growing types of plants. Like showier flowering plants, lawn grasses serve many of the same befits in a landscape as to flowering plants.
Ground Cover Plant Benefits
Ground cover plants generally serve the following purposes:
- Cover the soil to protect it from erosion by wind or water.
- Shade the soil to reduce the likelihood of undesirable plants to become established.
- Shade the soil to keep it cooler and reduce water loss from it.
- Occupy the soil itself with roots to compete with potentially invasive plants.
- Add beauty and interest to a landscape.
Most ground cover plants will spread out over or in the soil, producing new plants as they grow. Rhizomes are underground stems utilized by some plants like lily of the valley while stolons, spreading above ground stems, are produced by other plants like bugle weed. Grasses and other monocotyledonous plants may also produce rhizomes, stolons, offsets or tillers to expand the territory that they cover. These are all great characteristics for a ground cover to have, particularly in challenging locations like a hillside that is prone to erosion and needs to stabilization. However, that same propensity to spread can also make many of these plants aggressive competitors with other desirable plants that might also be in the landscape. So, choose your ground cover plants carefully so that you do not end up with a mass planting that is on its way to take over your garden a few years after planting.
Arabis caucasica (rockcress) is a good choice for a rock garden where it will receive full sun to part shade and have well-drained soils to grow in. Rockcress produces masses of white, four-petaled flowers in May on plants that grow only about 3 to 6” tall. Arabis creeps along the ground, forming roots as it grows so it can cover an ever-increasing area of a garden bed. Rockcress is heat and drought tolerant.
Armeria maritima (Sea Thrift) is a charming, small, clump-forming plant with grass-like leaves and rounded flower heads that come in bright pink or white. The primary flowering time is early summer but plants may rebloom off and on all summer and into the fall. When in bloom, plants typically grow about 6 to 8” tall. They will perform best in full sun to part shade. Since they have this clump-forming growth habit, it is best to plant them in groups or five or more. They can be used as an edging plant as well.
|Armeria maritima closeup.||Armeria maritima Splendens.|
Bergenia cordifolia (pigsqueek) is a great plant for many different types of sites in the garden performing well in shady locations to full sun, if extra moisture is provided. It looks great as a single specimen plant or planted in groups of five or more. Bergenia is not invasive, spreading slowly as new basal shoots develop on the plant. Lovely magenta-pink flowers emerge in early spring at about the same time that new foliage unfurls. The flower color of other varieties can range from white to dark pink. Soon the leaves spread out to about a foot wide and develop a nice glossy texture. The common name of “Pig Squeak” is derived from the sound one can make make a sound similar to that of a pig by rubbing a leaf with your fingers. When temperatures cool and days shorten in the fall, the leaves take on a burgundy color. The foliage is very freeze tolerant so it will look good all fall. It will persist through the winter, especially if given some mulch or snow cover. In the spring, simply cut back the old leaves to make room for the fresh foliage to emerge.
Cerastium tomentosum (snow-in-summer) is a low-growing, wooly-leaved plant that prefers a sunny location and to grow in a well-drained soil but can tolerate clay soil as long as it does not stay too wet for too long. Since it is drought and heat tolerant, it works well with other xeric plants that need little water. It has small white flowers in early to mid-summer that look great against its silvery foliage.
Lily of the Valley
Convallaria majalis (lily of the valley) has one of the most sweetly scented flowers of our perennial flowering plants. Each plant usually has only two or in some cases three fairly wide, strap-like leaves. A flower stalk grow up through the coiled leaves early in the spring to finally bloom usually in mid-May. Flowers are usually bright white but C. m. ‘Rosea’ has pink flowers. Convallaria is an aggressive spreader once established, increasing its territory through short rhizomes called pips that grow beneath the soil. It will spread out into the lawn but mowing should keep it. In some cases, one may want to use some sort of edging that extends about 6” below the soil line to keep it contained. Lily of the valley will tolerate full sun if it has adequate moisture; otherwise, it may show signs of scorch during hot and dry summer weather. Therefore, a partly shaded location is preferred but it will even tolerate shade.
Dianthus gratianopolitanus (Cheddar pink) is a lovely, finely textured type of pink or carnation. It forms a matt of small plants with opposite leaves that are only about 1/4” wide and 1 1/2” long. In early summer, the flower stems grow to about 6 to 12” tall. Flowers have a nice, spicy scent as well. Flower color may range from white to vibrant pink, as is the case with 2006 Perennial of the Year - ‘Firewitch’. Deadhead to encourage sporadic return bloom over the course of the summer and into the fall. Cheddar pinks grow best in full sun with well-drained soils. They are prone to rotting in overly wet locations.
Big Root Geranium
Geranium macrorrhizum (big root geranium) is just one example of the different hardy geraniums that can be grown in our gardens. While many gardeners are very familiar with the common annual geraniums, actually Pelargonium that are sold as bedding plants, hardy geraniums work well in many locations and can provide a nice floral display, attractive foliage as well as fall color in some cases. One of the best spreaders, and therefore a good ground cover is the big root geranium. It has leaves similar to a Pelargonium with their general rounded shape and slightly scalloped edge, but stays relatively short, only about 8 to 15” tall. In early summer many flower spikes develop, usually in shades of white, pink or lavender. Each flower spike will usually only have about six to 8 florets, fewer than the typical Pelargonium.
Lysimachia nummularia (moneywort) is another aggressive ground cover plant that only grows about 2 to 4” tall when in bloom. It has small, round, 3/4” opposite leaves that form along its thin, prostrate stems. This plant will form a dense mat of foliage that will block out most weeds. It looks great creeping over the edge of a wall or rocks and puts on quite a show when the small, bright yellow flowers appear in summer in profusion. The most commonly sold cultivar, ‘Aurea’ also has golden-yellow foliage. This plant will grow well in full to part sun.
Opuntia macrorhiza (prickly-pear) is a tough plant for tough sites, particularly hot, sunny locations with poor soils that are rocky or gravely or even high in clay, as long as the site is not too wet. While many gardeners might avoid prickly-pear cactus because of the sharp spines the flowers are very attractive and might be a strong enough attraction to make them worth adding them to your garden. Typically, the flowers are yellow to peach in color but new hybrids are becoming available with flowers that range in color from white to lavender, pink and red. Some gardeners may have had problems with Opuntias as weeds in their yard, certainly not a plant that you would want to step on while barefoot or even wearing light shoes.
Phlox subulata (moss phlox) has short needle-like, nearly evergreen foliage on fine, somewhat wiry stems. It will form a mat of foliage 12 to 24” wide and later flowers that will grow 3 to 6” tall. It grows best in a part to full sun location. Its flowers range in color from white, to pink, red-purple to violet-purple and appear in early spring. The flowers attract butterflies. Plants are deer and drought tolerant. However, they will perform best in humusy, well-drained soil with medium moisture.
|Phlox subulata lavender.||Phlox subulata pink closeup.|
Sedum sp. (stonecrop) is one of the most varied types of ground cover plants you can find at the garden center. Various species will grow from only a few inches tall to over two feet tall. Foliage can range in size from tiny, needle like scales to large, succulent leaves several inches long and over an inch wide. Their common name of stonecrop is well-deserved in that they often grow their best in sandy, rocky, well-drained soils and will often have a better chance of surviving a cold winter if they are in a dry location. Most species and cultivars have an impressive floral display during mid to late-summer of small, star-shaped flowers that may range in color from white to yellow, pink, lavender, pink, red or purple. Foliage may range in color from plain green to chartreuse or burgundy to nearly black. They all grow best in full sun but can take some shade.
|Sedum cauticola Lidakense flowers.||Sedum reflexum 'Blue Spruce' in bloom.|
Hens and Chicks, House Leek
Sempervivum tectorum (hens and chicks, house leek) is an interesting group of succulent plants with an attractive rosette type growth habit. The foliage is generally evergreen but may show some wilting over the winter. They are known as hen and chicks because in the spring they will send out small runners from the base of the plant that will sprout new baby plants, often referred to as the chicks. There are several different types and dozens of different cultivars ranging in foliage color and size. The arachnoidium type have what looks like webbing between the individual leaves. Sempervivums are monocarpic meaning that when an individual plant matures, it sends up a rather a flower stalk that may tower a foot tall over the 1 to 3” tall plants. Once the flowers are mature, that individual plant dies with its space to be taken over by a few of the chicks. This European native was commonly planted on the thatched roofs of homes where it was thought to bring good luck and also to help hold the thatch and later roof tiles together. Now it is mostly used in rock gardens or in containers. It has great drought tolerance and grows best in full sun.
|Sempervivum mixed types.||Sempervivum in spring.|
Stachys byzantina (lamb’s ears) has soft furry leaves that give this hardy perennial its common name. Like other fuzzy-leaved plants it is best planted in a sunny location. Avoid spots that will receive frequent sprinkler irrigation or shade as this will encourage rotting of the leaves. This member of the Mint family produces flower stalks about 15 to 20” tall in mid-summer that bear lavender pink flowers in the axils of the small leaves along the flower spike. Some people will just cut off the flower spikes when they develop to help reduce the chances of the plant spreading by seed and also because some gardeners find that the flower spikes detract from the appearance of the plant.
Mother of Thyme
Thymus serphyllum (mother of thyme) is a multi-purpose plant that makes an excellent and fairly aggressive ground cover that will out compete most weeds, provides pretty, delicate, lavender flowers that attract bees and other pollinators and the foliage has a nice fragrance when crushed. Thyme is often planted along walkways where the fragrant foliage may be brushed or stepped on while walking, to emit the fragrance. The stems and flowers may also be used as a flavoring for cooking or teas. Thy Tiarella cordata (foam flower) Thyme grows best in full sun to part shade and flowers mid-summer.
Veronica liwanensis (speedwell) is a low-growing counterpart compared to the other much taller species of Veronica. Growing only about 1 to 2” tall, it is easily overlooked in the garden but it certainly bears a much closer inspection, particularly when the small lavender flowers appear in early summer. It has tiny, glossy, oval leaves. It grows best in full sun in well-drained soils.
Vinca minor (common periwinkle) is a low-growing, twining, perennial plant with glossy, evergreen foliage. The smooth stems will often root down as they creep along the ground, making it an effective ground cover, particularly for stabilizing slopes. It produces tubular, lavender flowers in late spring and again intermittently over the course of the rest of the summer. It grows in average soils and performs best in full sun to part shade but it can also tolerate full shade.
Other Species & Cultivars
Of course, there are many other species and usually dozens of cultivars that you might find available at your local garden center or from online and catalog retailers. Various social media sites may also provide planting ideas. Just keep in mind that most of South Dakota is classified as USDA Hardiness Zone 4. Many interesting plants may not be hardy enough to survive in our climate. I encourage you to check out public gardens, like McCrory Gardens in Brookings, to see these and other ground cover plants utilized in a landscape setting to get a better idea if any of these are appropriate for your own garden.