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 vouchered herbarium specimen records 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: August 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

Before you buy

Your city may pay you to plant this

Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 452 programs across 44 states, each with a link to the provider and the date we last checked it.

Find rebates in your area

Browse plants for this ecoregion

Puget Lowland Marine West Coast Forest Northwestern Forested Mountains Sierra Nevada Central California Foothills and Coastal Mountains Central California Valley Southern California Mountains North American Deserts Central Basin and Range Mojave Basin and Range Southern Rockies Arizona/New Mexico Mountains Chihuahuan Deserts High Plains Southwestern Tablelands Northwestern Glaciated Plains Northwestern Great Plains Northern Glaciated Plains Western Corn Belt Plains Great Plains Northern Forests Northern Lakes and Forests North Central Hardwood Forests Driftless Area Southeastern Wisconsin Till Plains Central Corn Belt Plains Eastern Corn Belt Plains Northeastern Highlands Northeastern Coastal Zone Northern Allegheny Plateau Middle Atlantic Coastal Plain Northern Piedmont Ridge and Valley Interior River Valleys and Hills Madrean Archipelago Sonoran Basin and Range Acadian Plains and Hills Eastern Great Lakes Lowlands Atlantic Coastal Pine Barrens

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 vouchered herbarium specimen records 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 vouchered herbarium specimen records and regional native plant society lists. 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

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