How much sun does Mexican Dock need?

Mexican Dock grows best in full sun conditions.

When does Mexican Dock bloom?

Mexican Dock blooms in June, July, and August.

Where is Mexican Dock native?

Mexican Dock (Rumex triangulivalvis) is native to AZ, CA, CO, CT and 31 more states, per the USDA PLANTS Database and regional native plant society lists.

Is Mexican Dock toxic to dogs?

Yes. Mexican Dock is listed as toxic to dogs by the ASPCA Animal Poison Control Center (aspca.org). If your pet has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435.

Is Mexican Dock toxic to cats?

Yes. Mexican Dock is listed as toxic to cats by the ASPCA Animal Poison Control Center (aspca.org). If your cat has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435.

Is Mexican Dock HOA-friendly?

Mexican Dock takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

Mexican Dock

Name: Pollinator Patch
Author: Pollinator Patch

Rumex triangulivalvis

Last reviewed: July 2026

Mexican Dock is toxic to dogs and cats.

Listed as toxic by the ASPCA Animal Poison Control Center (opens in new tab) (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

Sierra Nevada Central California Valley Central California Foothills and Coastal Mountains Southern California Mountains Central Basin and Range Mojave Basin and Range Chihuahuan Deserts Sonoran Basin and Range

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.

Common questions

How much sun does Mexican Dock need?: Mexican Dock grows best in full sun conditions.
When does Mexican Dock bloom?: Mexican Dock blooms in June, July, and August.
Where is Mexican Dock native?: Mexican Dock (Rumex triangulivalvis) is native to AZ, CA, CO, CT and 31 more states, per the USDA PLANTS Database and regional native plant society lists.
Is Mexican Dock toxic to dogs?: Yes. Mexican Dock is listed as toxic to dogs by the ASPCA Animal Poison Control Center (aspca.org). If your pet has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435.
Is Mexican Dock toxic to cats?: Yes. Mexican Dock is listed as toxic to cats by the ASPCA Animal Poison Control Center (aspca.org). If your cat has been exposed, call the ASPCA Animal Poison Control Center at (888) 426-4435.
Is Mexican Dock HOA-friendly?: Mexican Dock 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.

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