How much sun does Smooth Dock need?

Smooth Dock grows best in part sun conditions.

When does Smooth Dock bloom?

Smooth Dock blooms in June, July, and August.

Where is Smooth Dock native?

Smooth Dock (Rumex altissimus) is native to AL, AR, AZ, CO and 36 more states, per the USDA PLANTS Database and regional native plant society lists.

Is Smooth Dock toxic to dogs?

Yes. Smooth 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 Smooth Dock toxic to cats?

Yes. Smooth 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 Smooth Dock HOA-friendly?

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

Smooth Dock

Name: Pollinator Patch
Author: Pollinator Patch

Rumex altissimus

Last reviewed: June 2026

Smooth 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

part sun

Water

medium

Size

24"–60" H × 12"–24" W

Bloom

Jun, Jul, Aug

Native to

AL, AR, AZ, CO and 36 more states

Browse plants for this ecoregion

Chihuahuan Deserts Central Oklahoma/Texas Plains Edwards Plateau Texas Blackland Prairies East Central Texas Plains South Central Plains

Smooth dock is a tall native perennial with large, smooth leaves and upright stems that produce clusters of small reddish-brown flowers in summer. This robust plant forms clumps and can reach 5 feet in height, making it suitable for background plantings or naturalized areas.

In an HOA neighborhood

Smooth 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.

Looks weedy and unkempt to most homeowners
Can spread aggressively and self-seed
Associated with marshy, wild areas rather than cultivated gardens

Wildlife value

The flowers provide nectar for various small pollinators including flies and beetles. Seeds are eaten by birds, particularly waterfowl and songbirds.

Common questions

How much sun does Smooth Dock need?: Smooth Dock grows best in part sun conditions.
When does Smooth Dock bloom?: Smooth Dock blooms in June, July, and August.
Where is Smooth Dock native?: Smooth Dock (Rumex altissimus) is native to AL, AR, AZ, CO and 36 more states, per the USDA PLANTS Database and regional native plant society lists.
Is Smooth Dock toxic to dogs?: Yes. Smooth 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 Smooth Dock toxic to cats?: Yes. Smooth 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 Smooth Dock HOA-friendly?: Smooth 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.

Pollinator Patch flags toxic plants like Smooth Dock and shows pet-safe natives for your ecoregion instead.

Find pet-safe natives

iPhone app Android app

Not sure where to start? Take the 2-minute yard quiz