Herb Robert is a branching, low growing winter and spring annual. It has light green leaves that are deeply dissected and release a pungent odor making this plant easy to recognize. As the plants mature the foliage turns red. This red color is very noticable under bright light conditions. The stems are highly pubescent, have multiple forks, and are brittle at the joints. The roots are shallow allowing for easy hand removal. The pink flowers are perfect and five petaled. The receptacle is elongated into a pointed structure called a "torus" or “storks bill”. Herb Robert reproduces only by seeds.

Flowers are usually self fertile creating uniform populations. Seeds are matured in elongated pointed capsules that eject their seeds up to 20 feet when disturbed. They can survive in the soil up to and probably beyond five years. (King county 2008) Herb Robert tolerates a wide range of light intensities thriving best in open canopied forests or along the edges of forests. It has been noted that this plant is also very happy under deeper shaded conditions. It can be highly competitive with native early spring forbs but less so against grasses. Often Herb Robert takes advantage of habitats that have been opened up through weed control activities such as English ivy or false brome removal.