Bastard Cress
Thlaspi arvense
Last reviewed: June 2026
Bastard Cress (Thlaspi arvense) is not on the ASPCA Animal Poison Control Center toxic plant list for dogs or cats (aspca.org (opens in new tab), last reviewed 2026-05-21). If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.
Light
full sun
Water
medium
Size
6"–24" H × 3"–12" W
Bloom
May, Jun, Jul
Native to
ND
Pollinators
bees, flies
Browse plants for this ecoregion
Bastard cress is a small annual wildflower that grows up to 2 feet tall with white flowers from May through July. This pioneer species often appears in disturbed soils and agricultural areas. It produces small heart-shaped seed pods that can be somewhat ornamental.
In an HOA neighborhood
Bastard Cress takes more care to keep looking intentional in a front yard. Maintenance level: low. Consider it for backyard or mid-zone beds rather than the street edge.
Works well in: backyard only.
- Common name includes 'bastard' which may cause complaints
- Often considered a weed in agricultural settings
- Can self-seed aggressively and spread beyond intended areas
Wildlife value
The small white flowers attract bees and flies during the late spring and early summer months. As an annual, it provides seasonal nectar sources for small pollinators.
Common questions
- How much sun does Bastard Cress need?
- Bastard Cress grows best in full sun conditions.
- When does Bastard Cress bloom?
- Bastard Cress blooms in May, June, and July.
- Where is Bastard Cress native?
- Bastard Cress (Thlaspi arvense) is native to ND, per the USDA PLANTS Database and regional native plant society lists.
- Is Bastard Cress toxic to dogs?
- Bastard Cress is not on the ASPCA Animal Poison Control Center toxic plant list for dogs (aspca.org).
- Is Bastard Cress toxic to cats?
- Bastard Cress is not on the ASPCA Animal Poison Control Center toxic plant list for cats (aspca.org).
- What pollinators does Bastard Cress attract?
- Bastard Cress draws bees and flies.
- Is Bastard Cress HOA-friendly?
- Bastard Cress takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.
Native range data from the USDA PLANTS Database and regional native plant society lists. Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
Ready to grow Bastard Cress? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.
Not sure where to start? Take the 2-minute yard quiz