Rumex crispus, curly-leaved dock
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Herbaceous

Rumex crispus

curly-leaved dock

PolygonaceaeEurope, western Asia

At a Glance

TypePerennial
HabitUpright
FoliageDeciduous
Height24-48 inches (60-120 cm)
Width12-24 inches (30-60 cm)

Growing Zones

USDA Hardiness Zones

3 - 9
Zone 3
Zone 4
Zone 5
Zone 6
Zone 7
Zone 8
Zone 9
These zones indicate the coldest temperatures this plant can typically survive.
Frost Tolerancehardy

Key Features

Drought Tolerant
Maintenancehigh

Overview

Rumex crispus is a taprooted perennial in the buckwheat family (Polygonaceae) reaching 24–48 inches (60–120 cm) tall with a 12–24 inch (30–60 cm) spread, arising from a stout, fleshy, yellow taproot that reaches 12–36 inches (30–90 cm) deep. Stems are erect, stiff, unbranched or sparingly branched, grooved. Basal leaves are lance-shaped, 6–12 inches (15–30 cm) long, with distinctly wavy-curled (crisped) margins — the primary identification feature and the source of the common name. Stem leaves are smaller, alternate, with papery ocreae at the nodes. Flowers are tiny, greenish, borne in dense whorls on elongated, branching panicles. Fruit is a triangular achene enclosed in 3 enlarged, heart-shaped valves (the inner tepals), each 0.12–0.2 inch (3–5 mm) long, usually with a single prominent grain (tubercle) on one valve. The fruit valves have entire (smooth) margins — a key distinction from R. obtusifolius. A single plant produces 20,000–60,000 seeds, viable in soil for 50–80 years. Contains oxalic acid; toxic to livestock in quantity. One of the most common perennial weeds in pastures, gardens, and disturbed ground in the Pacific Northwest.

Native Range

Native to Europe and western Asia, occurring in pastures, gardens, roadsides, and disturbed ground from sea level to approximately 8,000 feet (2,400 m). Naturalized across all 50 U.S. states and all Canadian provinces. One of the most common perennial weeds worldwide.

Suggested Uses

Used in Polygonaceae identification courses for teaching the fruit valve morphology (entire margins, single grain) compared with R. obtusifolius (toothed margins). The curly leaf margin is a standard leaf morphology teaching feature. The fleshy yellow taproot is used in root morphology exercises. The 50–80 year seed bank longevity is a primary teaching example in weed seed biology, surpassed in this collection only by Malva neglecta (100+ years). Seeds are consumed by ground-feeding birds.

How to Identify

Distinguished from Rumex obtusifolius (broad-leaved dock) by the lance-shaped leaves with curly-wavy margins (versus broad, ovate leaves with flat or slightly wavy margins), and the fruit valves with entire (smooth) margins and a single prominent grain (versus fruit valves with toothed margins). Distinguished from R. acetosella (sheep sorrel) by the much larger size (24–48 inches versus 4–18 inches), the large lance-shaped leaves (versus small arrow-shaped leaves), and the enlarged fruit valves (absent in R. acetosella). The curly leaf margins are visible from a distance and are diagnostic.

Appearance

Size & Dimensions

Height2' - 4'
Width/Spread1' - 2'

Colors

Flower Colors

green
red

Foliage Colors

green

Fall Foliage Colors

red

Bloom Information

Bloom Period

~4 weeks
J
F
M
A
M
J
J
A
S
O
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SpringSummer
Flowers from May through July. Dense, whorled panicles bloom from the base upward over 3–4 weeks. Wind-pollinated. Seeds mature by July in the Pacific Northwest. The reddish-brown seed stalks persist through fall and winter, remaining conspicuous for months.

Detailed Descriptions

Flower Description

Greenish, becoming reddish-brown at maturity

Foliage Description

Dark green, lance-shaped with distinctly wavy-curled (crisped) margins; long tapering base

Growing Conditions

Sun Requirements

Full Sun
Partial Shade
Requires 4-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.0 - 8.0(Neutral)
357912
Soil Types
loamclaysiltsand
Drainage
moist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

1-2 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Digging the fleshy yellow taproot is the most effective management; the entire top 8–12 inches (20–30 cm) must be extracted, as root fragments regenerate. A dock-digging tool or narrow spade is more effective than pulling. Cutting at ground level prevents seed set but the root crown resprouts vigorously. Repeated cutting every 2–3 weeks during the growing season over 2–3 years gradually depletes root reserves. The extremely long-lived seed bank (50–80 years) and massive seed production make eradication from established sites a multi-generational effort. Mowing before seed set in pastures reduces seed bank accumulation.

Pruning

No pruning applicable. Plants are dug, extracting 8–12 inches (20–30 cm) of the fleshy yellow taproot. Cutting the flower stalk before seed maturity prevents seed dispersal but the root crown resprouts. Seed heads must be bagged and removed if seeds have begun to mature.

Maintenance Level

high

⚠️ Toxicity Warning

Toxic to pets