The sudden appearance of purple flowers across a lawn, often in the early spring, signals that weeds have begun their seasonal takeover. These small plants frequently emerge before turfgrass has fully established its spring growth, creating distinct patches of color in yards and garden beds. Identifying the specific plant is the first step toward effective control, as different weeds require varied management strategies. The most common purple-flowered offenders are typically members of the mint family, which share a few tell-tale characteristics. Correct identification allows homeowners to choose the appropriate method for removal and prevention.
The Two Most Likely Culprits: Henbit and Purple Dead Nettle
The two most frequently mistaken purple weeds are Henbit (Lamium amplexicaule) and Purple Dead Nettle (Lamium purpureum). Both are winter annuals that germinate in the fall and flower in the spring. A quick inspection confirms they are in the mint family, as both have the characteristic square stem structure. However, the arrangement of their leaves is the clearest way to tell them apart.
Henbit features rounded or kidney-shaped leaves with scalloped edges that grow opposite each other along the stem. The upper leaves are sessile, meaning they lack a petiole (leaf stalk) and appear to directly clasp or wrap around the main stem. The flowers are pink to purplish and emerge in whorls from the leaf axils along the upper part of the stem.
Purple Dead Nettle has leaves that are more triangular or heart-shaped with prominent teeth along the margins. The key difference is that all of its leaves are attached to the main stem by a short petiole. The upper leaves often take on a noticeable reddish or purplish color, contributing to the plant’s overall hue.
Identifying Other Common Purple-Flowered Weeds
While Henbit and Dead Nettle are winter annuals, other common purple-flowered weeds are perennial and present a different control challenge. Ground Ivy (Glechoma hederacea), also known as Creeping Charlie, is a low-growing perennial that spreads aggressively through creeping stems (stolons) that root at the nodes. Its rounded or kidney-shaped leaves have scalloped edges and grow on long petioles, and the plant emits a minty odor when crushed.
Wild Violets (Viola species) also produce purple or blue-to-white flowers, but they have a distinct growth habit. These perennials grow in clumps, with all their heart-shaped leaves rising from a central point near the ground. Violets do not have a square stem and spread primarily through underground stems called rhizomes and by seeds. The foliage of Wild Violets also possesses a waxy coating, which makes them particularly difficult to control with many common treatments.
Management Strategies for Control
The life cycle of the weed dictates the most effective strategy for management. For winter annuals like Henbit and Purple Dead Nettle, which complete their life cycle by late spring, early intervention is most effective. Hand-pulling is feasible for small infestations, but this must be done before the plants set seed to prevent a larger issue the following year.
A healthy, dense turfgrass canopy is one of the best cultural defenses against weed invasion, as it competes for sunlight and resources. For chemical control, pre-emergent herbicides are designed to stop weed seeds from germinating and should be applied in the fall to prevent the germination of new winter annuals. Applying a second round of pre-emergent in early spring can help control summer-germinating weeds.
Perennial weeds, such as Wild Violets and Ground Ivy, are much tougher to eradicate due to their extensive root systems and spreading habits. They are most vulnerable to post-emergent herbicides in the fall when the plant is actively transporting nutrients down to its roots in preparation for winter dormancy. This systemic movement draws the herbicide deeper into the plant, providing a better chance of killing the entire root structure. When using any herbicide, ensure the product is labeled for the specific weed and follow all application instructions regarding temperature and timing.
Safety and Consumption Considerations
Many of the common purple-flowered weeds found in yards are non-toxic and considered edible. Both Henbit and Purple Dead Nettle are safe for human consumption, with all above-ground parts being used in salads or cooked preparations. Wild Violets are also generally considered edible, including the flowers and leaves. Ground Ivy is safe to consume in moderation, often used for its aromatic qualities. However, it is important to exercise extreme caution before consuming any foraged plant, ensuring it is correctly identified and has not been treated with pesticides or herbicides.