Tall Dock Plant Care
Rumex altissimus Alph.Wood
Updated · Sources · How we source care data
Rumex altissimus, the pale dock, is a widespread species of flowering plant in the family Polygonaceae, native to southern Ontario, the United States east of the Rockies, and northern Mexico. A perennial of rich wet to mesic soils, and reaching 4 ft (1.2 m) with yellowish-green to green flowers, it is wind-pollinated.
Every 4–7 days
Full sun to part shade
50–75°F
40–70%
At a glance
How do you care for Tall Dock?
Water Tall Dock every 4–7 days, letting the top layer of soil dry out between waterings, and give it full sun to part shade. It prefers temperatures of 50–75°F (10–24°C) and 40–70% humidity. Fertilize it every 6 months during the growing season. It is reported as toxic to pets, so keep it out of reach of pets.
Where Is the Tall Dock Native To?
What Is the Tall Dock?
Tall Dock (Rumex altissimus) belongs to the Polygonaceae family within the Rumex genus. Tall Dock is native to southern Ontario, the United States east of the Rockies, and northern Mexico. Tall Dock is also known as Smooth Dock.
Tall Dock displays a clumping perennial growth habit, reaching up to 2 ft tall with a spread of approximately 1.5 ft. Tall Dock produces small green flowers on tall spikes.
Leaf size: approximately 6 inches.
How Often Should You Water a Tall Dock?
Rumex altissimus requires watering every 4–7 days. Allow the top layer of soil to dry between waterings to prevent root rot. Reduce watering frequency during winter when growth slows.
Watering Frequency
Every 4–7 days
Let soil partially dry between waterings
What Light Does the Tall Dock Need?
Tall Dock thrives in full sun to part shade.
Light Requirement
Full sun to part shade
What Temperature and Humidity Does the Tall Dock Prefer?
Rumex altissimus grows best at temperatures of 50–75°F. Tall Dock prefers humidity levels of 40–70%.
Temperature
50–75°F
Humidity
40–70%
What Soil Mix Works Best for a Tall Dock?
Moist, fertile soil with good drainage. Good drainage is essential for Tall Dock to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Tall Dock?
Feed Tall Dock every 6 months during the growing season (spring and summer) with a balanced fertilizer diluted to the strength on the label.
Pause feeding in autumn and winter, when growth slows, and never fertilize dry soil — water first.
Fertilizing
Every 6 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
How Do You Repot a Tall Dock?
Divide clumps every 2-3 years in early spring. Choose a pot one size larger than the current container, and ensure it has drainage holes to allow excess water to escape.
How Do You Propagate a Tall Dock?
Tall Dock can be propagated through seeds, division. Similar propagation techniques also apply to alpine dock plant care, which shares the same genus.
Is the Tall Dock Toxic to Pets and Children?
Toxic (caution)
Reported as toxic in our plant data. Not verified by the ASPCA.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the Tall Dock?
Tall Dock is susceptible to aphids, leaf miners, slugs. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
What USDA Hardiness Zone Does the Tall Dock Need?
Tall Dock grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Tall Dock is native to southern Ontario, the United States east of the Rockies, and northern Mexico. In cooler regions, grow Tall Dock as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
Tall Dock is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Rumex genus — compare its care with other Rumex species on PlantoScan.
Rumex is part of the Polygonaceae plant family — browse all Polygonaceae genera and species.
Tall Dock thrives in bright light and direct sun — see other bright-light plants.
More Rumex Species
Other Rumex species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Rumex altissimus Alph.Wood, family Polygonaceae (first published in Proc. Amer. Assoc. Advancem. Sci. 1853: 177 (1853)) — World Flora Online record, IPNI name record.
- Pet toxicity: Tall Dock is reported as toxic to pets in our plant data (not verified by the ASPCA), so treat it with caution. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Hardiness zone: USDA Zone 12a, calculated from the plant's minimum temperature.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
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