Smooth Dock
Rumex altissimus
Last reviewed: June 2026
Smooth 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
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
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.
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.