Cowflock
Caltha palustris
Last reviewed: July 2026
Caltha palustris is a native wetland perennial blooming bright yellow from April through June across northeastern and midwestern states. This marsh marigold thrives in wet soils and attracts diverse pollinators including bees and flies.
The USDA PLANTS Database (opens in new tab) does not flag Cowflock as toxic to livestock.
Light
part shade
Water
high
Size
8"–24" H × 12"–24" W
Bloom
Apr, May, Jun
Native to
CT, DE, IA, IL and 26 more states
Pollinators
bees, flies, beetles
Deer
Resistant (per Prairie Moon Nursery)
Marsh marigold is a cheerful spring wildflower that produces bright yellow buttercup-like blooms from April through June. This low-growing perennial thrives in consistently moist to wet soils and partial shade, making it perfect for rain gardens or boggy areas. The glossy heart-shaped leaves emerge early in spring and may go dormant during hot, dry summer periods.
Growing Cowflock
Grow Cowflock in part shade and high water. Mature plants reach 8 to 24 inches tall and spread 12 to 24 inches wide. Expect low maintenance to keep it looking intentional in a front yard.
In an HOA neighborhood
Cowflock 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.
- Goes completely dormant in summer leaving bare spots
- Requires consistently wet soil which may look swampy
- Wild wetland appearance doesn't suit formal landscapes
Wildlife value
The early spring flowers provide crucial nectar for bees, flies, and beetles when few other plants are blooming. Seeds may attract waterfowl and other wildlife in wetland settings.
Common questions
- When does Caltha palustris bloom?
- Caltha palustris blooms from April through June, producing bright yellow buttercup-like flowers in early to mid spring.
- What growing conditions does marsh marigold prefer?
- Marsh marigold thrives in consistently moist to wet soils and tolerates partial sun to full shade. It naturally grows in marshes, swamps, and along stream banks.
- What pollinators visit Caltha palustris?
- Caltha palustris attracts various pollinators including bees, flies, and beetles. The early spring blooms provide important nectar when few other flowers are available.
- Where is Caltha palustris native?
- Caltha palustris is native across much of the northern United States, from Maine to North Dakota and south to North Carolina and Missouri, with populations also in Oregon and Washington.
- Is Cowflock toxic to cats?
- Yes. Cowflock is listed as toxic to cats by the Cornell University Poisonous Plants Database (aspca.org). If your cat has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435.
- Is Cowflock toxic to livestock?
- The USDA PLANTS Database does not flag Cowflock as toxic to livestock.
- Is Cowflock HOA-friendly?
- Cowflock 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 Cowflock? 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