It can be recognized by its small, scalloped leaves that wrap around the stem and clusters of tiny purple flowers, which might seem inviting at first. However, this weed spreads quickly and can ...

Stems are 1 to 4 feet tall, ridged, branching above. Leaves are alternate, lacking petioles, oblong or lance-shaped, divided into spiny-tipped irregular lobes. Flowers are unisexual, on separate ...