A ground cover is a low-growing plant that spreads horizontally to cover the soil surface, providing weed suppression and erosion control. Purple varieties, ranging from lavender to deep burgundy, are sought after for the visual contrast they provide in a landscape. This striking color highlights green foliage or creates a vibrant carpet over bare earth. Identifying the specific purple ground cover requires distinguishing between common ornamental garden plants and widespread weeds.
Primary Candidates for Purple Ground Cover
Common ornamental choices include Bugleweed (Ajuga reptans), a perennial prized for its deep purple or bronze foliage that retains color throughout the season. Another popular option is Creeping Phlox (Phlox subulata), which creates a dense, flowering blanket of purple, pink, or blue in early spring before receding to a mat of green foliage.
The most likely candidate for a purple plant growing uninvited in lawns is Purple Dead Nettle (Lamium purpureum). This plant is a winter annual weed that germinates in the fall and completes its life cycle by flowering and setting seed in the spring. Although it offers an early source of nectar for pollinators, it is classified as a weed in manicured settings. Cultivated Dead Nettle (Lamium maculatum) is a separate, well-behaved perennial ground cover with variegated leaves and purple flowers.
Key Differences in Plant Structure and Growth
A careful examination of the plant’s structure provides the most reliable way to identify the purple ground cover. Purple Dead Nettle (Lamium purpureum) is recognizable by its distinct, square-shaped stem, a characteristic feature of the mint family. Its upper leaves are often intensely purple and appear somewhat heart-shaped with rounded teeth. This weed’s growth is upright and clumping, typically reaching 4 to 8 inches in height before dying back in the late spring.
In contrast, Ajuga reptans spreads aggressively along the ground via stolons (above-ground runners) that root at the nodes to form a dense, mat-like carpet. Its leaves are broad, rounded, and often boast a dark, glossy purple or bronze coloration, depending on the cultivar and sun exposure. The purple flowers of Ajuga appear on short, upright spikes, typically blooming from mid-spring into early summer.
Creeping Phlox (Phlox subulata) forms a dense, low cushion, typically no more than six inches tall, composed of narrow, stiff, needle-shaped leaves. Its flowers are spectacular, covering the entire mat in a solid sheet of five-petaled, star-shaped blossoms for three to four weeks in the early spring. Phlox subulata spreads primarily through its creeping growth habit and by reseeding, forming a non-invasive cushion.
Cultivation and Control of Purple Ground Covers
If you have an ornamental variety like Ajuga reptans, promote deep purple pigmentation by ensuring it receives a few hours of sun; insufficient light can cause the foliage to revert to green. Its vigorous nature requires the installation of edging barriers, such as a six-inch deep strip of plastic or metal, to prevent encroachment on lawns or adjacent garden beds. A light application of a balanced, low-nitrogen fertilizer in the spring helps maintain plant health without promoting excessive green growth.
For Creeping Phlox, successful cultivation requires full sun and exceptionally well-drained soil, as the plants are intolerant of perpetually wet conditions. A light shearing after its spring bloom encourages denser foliage and maintains a tidy, compact appearance. If the plant is Purple Dead Nettle, control is best achieved through mechanical removal, as this winter annual is easily pulled from the ground. Applying a pre-emergent herbicide in late summer or early fall can prevent establishment, while a thick layer of mulch will suppress its growth.