Bitter cress is a common name for two species of plants in the mustard family: Cardamine hirsuta and Cardamine flexuosa. These plants are often found growing as weeds in lawns, gardens, containers, and other disturbed areas. They have small white flowers and pinnate leaves that resemble those of watercress. Bitter cress can be a nuisance for gardeners, as it produces large amounts of seeds that are dispersed by an explosive mechanism. However, bitter cress also has some benefits: it can be eaten as a salad green, and it attracts pollinators and beneficial insects.
How to Identify Bitter Cress
Bitter cress can be easily confused with other members of the mustard family, such as cuckoo flower, shepherd’s purse, or pennycress. Here are some features that can help you distinguish bitter cress from its relatives:
Bitter cress has four stamens (the male parts of the flower), while most other mustards have six.
Bitter cress has rounded leaflets on its basal leaves (the leaves at the base of the plant), while most other mustards have pointed or lobed leaflets.
Bitter cress has hairless stems, while some other mustards have hairy stems.
Bitter cress has wavy or flexuous stems, while some other mustards have straight or erect stems.
Bitter cress has narrow seed pods that overtop the flowers, while some other mustards have broader seed pods that do not overtop the flowers.
You can also use the following table to compare the two species of bitter cress:
| Feature | Hairy bitter cress (C. hirsuta) | Wavy bitter cress (C. flexuosa) |
| — | — | — |
| Life cycle | Annual or biennial | Biennial or perennial |
| Height | 3 to 10 inches | Up to 18 inches |
| Habitat | Dry or moist soils, full sun or shade | Moist or wet soils, shade |
| Flowering time | Early spring | Spring to summer |
| Leaf arrangement | Alternate | Opposite |
How to Control Bitter Cress
If you want to get rid of bitter cress in your lawn or garden, you have several options:
Mowing: Frequent mowing in early spring can prevent bitter cress from flowering and producing seeds. However, this may not be effective if the plants are already established or growing in shady areas.
Cultivation: Hoeing or hand-pulling bitter cress before it sets seed can reduce its population. However, this may also disturb the soil and create favorable conditions for new seedlings to germinate.
Mulching: Applying a thick layer of organic mulch around your plants can suppress bitter cress growth by blocking light and moisture. However, this may also attract slugs and other pests.
Herbicides: You can use preemergence or postemergence herbicides to control bitter cress. Preemergence herbicides prevent seed germination, while postemergence herbicides kill existing plants. Some examples of herbicides labeled for bitter cress control are dimethenamid, dithiopyr, sulfentrazone + prodiamine, and isoxaben. Always follow the label instructions and precautions when using herbicides.
How to Use Bitter Cress
If you don’t mind having bitter cress in your lawn or garden, you can actually enjoy its benefits:
Eating: Bitter cress leaves and flowers have a peppery, cress-like flavor that can be added to salads, sandwiches, soups, or stir-fries. You can harvest them throughout the year, but