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Bastard Cress

Thlaspi arvense

Last reviewed: October 2026

Bastard Cress (Thlaspi arvense)
Photo: (c) gonodactylus, some rights reserved (CC BY), uploaded by gonodactylus

Toxicity unknown

Bastard Cress (Thlaspi arvense) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. 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

Pollinators

bees, flies

Native alternatives to Bastard Cress

Bastard Cress is not native to the United States. These natives fill a similar role in a planting, matched on bloom season, bloom color and mature size.

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Wondering what could grow where Bastard Cress is now? Upload a photo of the spot and Patch Vision shows a rendering of it replanted with natives for your region.

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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.

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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.
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.

Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.

If something looks wrong

Common plant problems, and what to check first

These come up on almost any plant. Each guide lists the likely causes in the order they are worth ruling out, with one thing to check before you act on any of them, and links to the source it came from.

See all plant problem guides

Ready to grow Bastard Cress? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.

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