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 32 more states, per vouchered herbarium specimen records 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: October 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) 426-4435 and your veterinarian's emergency line.

Pollinator Patch flags toxic plants so you can choose a pet-safe native alternative for your yard.

Native swaps for a yard with pets

Smooth Dock is listed as toxic to dogs by the ASPCA Animal Poison Control Center. These natives fill a similar role in a planting and are not on the ASPCA toxic plant list for dogs or cats. Each plant's page carries its dated record.

Light

part sun

Water

medium

Size

24"–60" H × 12"–24" W

Bloom

Jun, Jul, Aug

Native to

AL, AR, AZ, CO and 32 more states

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Browse plants for this ecoregion

Southern Rockies North American Deserts Arizona/New Mexico Mountains Chihuahuan Deserts High Plains Southwestern Tablelands Central Great Plains Great Plains Cross Timbers Edwards Plateau Texas Blackland Prairies East Central Texas Plains South Central Plains Eastern Temperate Forests Ozark Highlands Central Irregular Plains Northwestern Glaciated Plains Northwestern Great Plains Piedmont Northern Glaciated Plains Western Corn Belt Plains Northern Lakes and Forests North Central Hardwood Forests Driftless Area Southeastern Wisconsin Till Plains Central Corn Belt Plains Eastern Corn Belt Plains Southern Michigan/Northern Indiana Drift Plains Huron/Erie Lake Plains Northeastern Highlands Northeastern Coastal Zone Northern Allegheny Plateau Erie Drift Plain Northern Forests Middle Atlantic Coastal Plain Northern Piedmont Southeastern Plains Ridge and Valley Western Allegheny Plateau Interior Plateau Interior River Valleys and Hills Mississippi Alluvial Plain Mississippi Valley Loess Plains Madrean Archipelago Atlantic Coastal Pine Barrens

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 32 more states, per vouchered herbarium specimen records 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 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.

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