Ground cover refers to low-growing, spreading plants used to cover bare soil in the landscape. These plants generally stay under one foot in height and form a dense mat of foliage. Seeking a rapid grower is necessary because quick coverage is the most effective method for suppressing weeds and stabilizing soil on slopes and banks. In shaded areas, such as beneath mature trees or on the north side of a structure, the challenge is amplified by reduced light and competition from tree roots. Fast-spreading ground covers offer an aesthetic solution while protecting the topsoil from erosion and the drying effects of wind.
Understanding Rapid Spread Mechanisms in Shade
The speed of a ground cover’s spread, especially in low-light environments, is primarily determined by its vegetative reproductive strategy. Plants that achieve rapid lateral expansion do so by bypassing the slower process of seed production and germination. This horizontal colonization is accomplished through specialized stem structures that allow the plant to continually root and establish new clones.
One mechanism involves the use of stolons, which are above-ground, horizontal stems that trail along the soil surface. At various points, or nodes, along the stolon, the plant will develop adventitious roots and new vertical shoots, effectively creating a new individual plant rooted to the main system. This method, seen in plants like Creeping Myrtle, allows the plant to quickly “run” across a patch of ground and form a dense, interconnected mat.
Alternatively, some of the fastest spreaders utilize rhizomes, which are modified underground stems that grow horizontally beneath the soil. The rhizome stores energy and generates new roots and shoots from its nodes, allowing the plant to pop up new growth some distance away from the original plant. This subterranean method of growth is difficult to control because the underground network is often extensive and can quickly resprout from small, remaining fragments.
Top Contenders: Proven, Rapidly Spreading Ground Covers
One of the fastest-spreading options is Bishop’s Weed (Aegopodium podagraria), often called Goutweed. This plant forms dense patches quickly by utilizing a rhizomatous root system. The non-variegated, solid-green form is especially fast in shade, as it possesses a higher photosynthetic rate in low light compared to its variegated counterpart.
English Ivy (Hedera helix) spreads rapidly and extensively by rooting stems that readily form adventitious roots wherever they touch the soil. While ivy is highly shade-tolerant and forms a dense, year-round evergreen carpet, it is an aggressive invader that can climb and smother trees, leading to decline and increased vulnerability to blow-over.
Creeping Myrtle (Vinca minor), also known as periwinkle, spreads quickly via rooting stems, or stolons. It forms a low-mounding carpet and is valued for its glossy foliage and small, lavender-blue flowers in spring. It is classified as an invasive species in many regions, capable of displacing native plants.
A fourth fast-growing option is Yellow Archangel (Lamium galeobdolon). It spreads rapidly by rooting stems and is notably vigorous in dense shade, easily smothering smaller plants in its path. The cultivar ‘Variegatum’ is commonly used for its attractive silver-mottled foliage, but it is still considered invasive in some parts of the country.
Matching Ground Covers to Specific Shade Conditions
Selecting a plant based on the specific type of shade and moisture available is necessary for successful establishment. Shade is categorized by the amount of direct sunlight received, which impacts the plant’s photosynthetic capability. Deep or full shade refers to areas that receive less than two hours of direct sun, such as the north side of a building or a dense woodland understory.
Plants like Yellow Archangel and the non-variegated Goutweed thrive in these deep shade conditions. Both species maintain vegetative growth even when light is severely limited. Partial or dappled shade, which receives between two and four hours of filtered or morning sun, allows nearly all fast-spreading shade ground covers to thrive, including Creeping Myrtle and English Ivy.
Dry shade is typically found directly beneath mature trees where the canopy blocks rain and the tree roots absorb most of the soil moisture. For this challenging spot, Creeping Myrtle is effective, as it is drought-tolerant once established and does not compete heavily with large tree roots for moisture. Yellow Archangel can also tolerate dry sites once established, especially if the soil is rich in humus. Proper site preparation, including incorporating organic matter into the soil, is necessary to ensure the quickest possible establishment and spread.