Creeping Charlie (Glechoma hederacea), also known as ground ivy, is a common, persistent weed found in lawns and gardens. This invasive perennial creeper is known for its rapid, mat-forming growth and is a member of the mint family. Recognizing its specific physical features is the first step in managing its spread.
Key Characteristics for Identification
The primary physical trait of Creeping Charlie is its stem structure. The stems have a square cross-section, a feature easily felt by gently rolling a stem between your fingers. These stems sprawl along the ground, rooting easily at the nodes as they creep, allowing the plant to form dense, low-lying patches.
The leaves are another clear indicator, typically being round to kidney-shaped, or reniform, with a diameter of about half an inch to an inch and a half. They are attached to the stem by long leaf stalks and are arranged oppositely. The edges of the dark green leaves are scalloped, giving them a rounded, toothed appearance.
Creeping Charlie grows as a low, aggressive mat close to the soil surface. It thrives particularly well in moist, shady environments, although it can tolerate more sun exposure. This dense groundcover spreads vegetatively as the vining stems continually root at the nodes.
The Role of Flowers and Scent
Creeping Charlie produces small, distinctive flowers that appear in the spring, typically blooming from March through June. These blooms are funnel-shaped and bilaterally symmetrical. The color is usually bluish-purple or lavender, and they are situated in clusters of two or three in the leaf axils, where the leaves join the stem. The flowers are two-lipped, with the lower lip often featuring dark spots or streaks that guide pollinators.
The plant’s aromatic quality provides a strong identification clue, especially when disturbed. When crushed, the foliage releases a strong, pungent, mint-like odor. This distinctive scent confirms its identity as a member of the mint family. This aroma is often more powerful than that of similar-looking weeds.
Distinguishing Creeping Charlie from Look-Alikes
Several other plants can be mistaken for Creeping Charlie, including common mallow, henbit, and wild violet. The square stem is a simple way to rule out many contenders, as common mallow does not possess this feature. Common mallow also has rounded leaves, but they attach to the stem at the back of the leaf, unlike Creeping Charlie’s central attachment.
Henbit, another member of the mint family, also has a square stem and similar-colored flowers. However, henbit is a winter annual that dies off in the late spring, whereas Creeping Charlie is a perennial. Furthermore, henbit’s upper leaves are stalkless, directly fusing to the stem, a difference not seen in Creeping Charlie.
When comparing it to wild violet, the key difference lies in the leaf margins and the scent. Wild violet leaves are heart-shaped with sawtooth-like serrations, while Creeping Charlie has pronounced, rounded scalloped edges. Wild violet also does not emit the strong, minty fragrance when its leaves are crushed, which is a defining feature of Creeping Charlie.