Garlic mustard has different forms throughout its life (see the life cycle diagram). From the time it’s a seedling until the following spring, it has a low form with round leaves with scalloped edges. Warmer days in April cause garlic mustard to bolt, growing long stalks with clusters of four-petaled white flowers. When mature, the leaves change from circular to triangular, but keep the scalloped edges. Crushed leaves and roots often smell like garlic, though not always. Plants are typically 12 to 48 inches tall, though plants as short as 1 inch or as tall as 72 inches are not all unusual.

After flowering in April and May, long narrow seed pods form in early June. It’s important to note that the seeds in these pods take several weeks to ripen; the management season for garlic mustard often extends into early July. At that point, pods are dry and explode when you touch them, scattering black, oblong seed that can survive from five to ten years in the soil. Pulling plants in this stage risks getting ripe seed all over you, and then spreading it elsewhere. Well-meaning ecologists can become the perfect garlic mustard delivery system! (see life cycle diagram)