Swinecress

Coronopus didymus

Swinecress is a winter annual broadleaf weed that is also known as Wild Tansy, Hog-weed, Bitterweed, Mayweed, Hay-fever Weed, Blackweed, Roman Wormweed and Annual Ragweed. Its scientific name is Coronopus didymus.

Identify

Alternate

Pinnatifid

Swinecress can be identified as a freely branched, laterally growing broadleaf weed. Its leaves are divided into numerous small segments, and its stems are usually partly angular or grooved. Swinecress foliage produces a strong, pungent odor when broken, cut or crushed. Blooming in April through October, Swinecress produces tiny white flowers arranged in clusters at the ends of stems and leaf axils. Reproduction occurs by seeds.

Life Cycle

This broadleaf weed is often found growing in open fields, waste areas, lawns and gardens. Swinecress can be found throughout much of the United States.

Control

Coronopus didymus can be a quickly spreading weed and is frequently found in lawns and gardens. Cultural weed control methods such as proper lawn mowing may help prevent the weed from entering your lawn. However, once present in your lawn, professionally applied broadleaf weed killers are usually best for control.