Mexican Dock
Rumex triangulivalvis
Last reviewed: June 2026
Mexican Dock is toxic to dogs and cats.
Listed as toxic by the ASPCA Animal Poison Control Center (last reviewed 2026-05-21). If your pet has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435and your veterinarian's emergency line.
Pollinator Patch flags toxic plants so you can choose a pet-safe native alternative for your yard.
Light
full sun
Water
low
Size
12"–36" H × 6"–18" W
Bloom
Jun, Jul, Aug
Native to
AZ, CA, CO, CT and 31 more states
Browse plants for this ecoregion
Willow dock is a native perennial with triangular-shaped leaves and tall spikes of small, reddish-brown flowers in summer. This drought-tolerant plant grows in clumps and can spread moderately in favorable conditions. The foliage dies back in winter, leaving behind dried seed stalks that persist into fall.
In an HOA neighborhood
Mexican Dock 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.
- Considered a weed by many homeowners
- Can spread aggressively
- Dried stalks look unkempt in fall
Wildlife value
The flowers attract small beneficial insects and flies, while the seeds provide food for birds and small mammals. The plant serves as a host for several butterfly larvae.
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.
Pollinator Patch flags toxic plants like Mexican Dock and shows pet-safe natives for your ecoregion instead.