Winter annual broadleaf weeds are beginning to become apparent in some lawns. These weeds germinate in the fall, grow over the winter months, and reproduce in the spring.
Common Winter Annuals:
Hairy bittercress (Cardamine hirsute)
Bittercress is a common broadleaved winter annual weed that is present in most lawns this time of year. It germinates in the fall and grows over the winter, going to seed and flowering in early-mid spring. It has round to wedge-shaped leaf segments that are typically hairy on the upper surface. This weed starts as a small rosette and matures into a large, branching plant with small white flowers. The fruit is a long, slender capsule that often ascends past the adjacent flower.
Henbit (Lamium amplexicaule) and Purple deadnettle (Lamium purpureum)
Henbit is a common winter annual weed found in lawns. It branches freely from the base stems which are green or purple in color. The leaves are rounded, coarsely toothed, hairy and deeply veined. Flowers are in whorls in the axils of the upper leaves. Petals are purple and fused into a two-lipped tube.
Purple deadnettle is very similar in appearance. However, the upper leaves of deadnettle have petioles, whereas henbit does not. Deadnettle also has upper leaves that are distinctly red- or purple-tinged. The leaves are more triangular and less deeply-lobed. The flowers are lighter purple than those of henbit. Purple deadnettle and henbit both have distinctive four-sided (square) stems, and flower in early spring.
Common Chickweed (Stellaria media)
Common chickweed is a low-spreading winter annual or perennial weed with a weak, shallow root system. The prostrate stems often root at the nodes. Its spreading growth covers adjacent turf and seriously impedes turf growth. Chickweed often forms extensive, dense patches. Stems have vertical lines of hairs. Small white flowers are in clusters at the end of the stems.