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Curly Dock

Pennsylvania weed ID · Lawn broadleaf

Curly Dock

Rumex crispus · Polygonaceae (buckwheat family)

Perennial
Broadleaf
Non-native

Those tall, rust-brown seed stalks standing in a ditch or pasture all winter — and the clump of wavy leaves you keep mowing over in the lawn — are curly dock.

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Quick ID

Long, narrow leaves with wavy, crinkled edges like lasagna noodles
Thin papery sheath where each leaf stalk meets the stem
Tall seed stalks that turn rusty brown in summer and stand all winter
Thick yellow-orange taproot
Hairless leaves, sometimes with a reddish tinge

Fact sheet

Scientific name: Rumex crispus
Family: Polygonaceae (buckwheat family)
Also called: Curled dock, Yellow dock, Sour dock
Life cycle: Perennial
Native to PA?: No — native to Europe and western Asia
Height: Leafy rosette about 1 ft tall; flower stalks 2–4 ft
Leaves: Long, narrow, lance-shaped leaves 6–12 in long with strongly wavy, crinkled edges; hairless, sometimes tinged red; mostly in a basal rosette
Flowers: Tall, branched stalk crowded with small greenish flowers from late spring into summer, turning reddish-brown as seeds ripen
Seeds / fruit: Shiny, reddish-brown, three-sided seeds wrapped in papery, heart-shaped wings; dead rusty-brown seed stalks stand through winter
Roots: Thick, fleshy, yellowish taproot that can resprout from the top few inches if broken
Spreads by: Seed (in large numbers, long-lived in soil); regrowth from the taproot crown
Where you’ll find it: Thin lawns, pastures, hayfields, roadside ditches, wet low spots and field edges; common on heavy, damp soils but also tolerates dry ground
When you’ll see it: Rosettes green from early spring to late fall; flower stalks rise in late spring; rust-brown seed stalks are the giveaway in late summer and winter
Toxicity: Leaves contain oxalates; large amounts can sicken livestock and the plant is not a safe forage. Young leaves are eaten as greens in small amounts by foragers, but avoid large quantities.
PA status: Not regulated in PA
Difficulty to control: Moderate
Best time to act: Dig or treat rosettes in fall (September–October) or in spring before flower stalks form; cut seed stalks before they turn brown

What is curly dock?

Curly dock is a tough perennial weed from Europe that has made itself at home in lawns, pastures and roadsides across Pennsylvania. It grows from a thick yellow taproot and throws up tall seed stalks that turn rusty brown and stand through the winter. Curly dock identification is straightforward once you notice the wavy-edged leaves and that brown seed stalk.

It’s in the buckwheat family, the same group as smartweeds and knotweeds. In a lawn it’s mostly a nuisance, but in hayfields and pastures it’s a real problem because livestock avoid it and it can make them sick in quantity.

Curly dock identification: what to look for

For most of the season, curly dock is a low rosette of leaves. In late spring a flower stalk shoots up out of the middle.

Leaves: Long and narrow, usually 6 to 12 inches, with edges that are strongly ruffled or crinkled, a little like a lasagna noodle. They’re hairless and sometimes have a reddish tint.
Sheath: Where each leaf stalk joins the stem there’s a thin, papery sleeve wrapped around the stem. This is a trademark of the buckwheat family.
Flower stalk: A stiff, branched stalk 2 to 4 feet tall carries crowded clusters of small greenish flowers. As the seeds ripen, the whole stalk turns reddish and then a deep rusty brown.
Seeds: Shiny, three-sided seeds wrapped in papery, heart-shaped wings, produced by the thousands on one plant.
Root: A thick, fleshy taproot, yellow to orange inside.

Where it grows in Pennsylvania

Curly dock does especially well on heavy, damp ground, so it’s common in low spots, along ditches and in the clay soils of central PA river valleys. It also handles dry, poor ground, which is why you’ll see it on gravel road shoulders too.

In lawns it shows up where the turf is thin: around downspouts that keep the ground soggy, in compacted areas and along edges that get scalped by the mower. Regular mowing keeps it from seeding, but the rosette just keeps coming back.

Curly dock look-alikes

Broadleaf dock is its closest look-alike. Its leaves are much wider, often with a heart-shaped base and reddish veins, and they’re only slightly wavy. Both are managed the same way.

Young common burdock rosettes are sometimes mistaken for dock, but burdock leaves are much broader, heart-shaped and fuzzy-white underneath. Red sorrel is a small relative with arrowhead-shaped leaves.

When in doubt, check the stem. Docks and sorrels have that thin papery sheath where the leaf stalk meets the stem, and their seed stalks turn rusty brown. Burdock has neither, and in its second year it grows prickly burs instead.

How to get rid of curly dock

Dock regrows from buds near the top of its taproot. If you dig, you need to get the top several inches of root; if you just snap off the leaves, it’ll be back in two weeks.

Dig it: For a few plants, use a long dandelion fork or a narrow spade after a good rain. Go straight down beside the root and lever it out, aiming to remove at least the top 2 to 4 inches of taproot. Fill and reseed the hole.
Cut the seed stalks: If you can’t deal with the plant right away, at least cut the flower stalk before it turns brown. That stops thousands of seeds from hitting the ground.
Fix the wet spot: If dock keeps coming back in the same soggy area, the drainage is the real issue. Redirecting a downspout, regrading a low spot or installing a French drain lets grass compete again. Pulling dock out of ground that stays wet is a losing game until the water problem is solved.
Herbicide: In lawns, broadleaf herbicides containing 2,4-D, dicamba, MCPP (mecoprop) or triclopyr control dock when sprayed on actively growing plants. Fall is the best time, with spring second, and a repeat treatment is often needed. Don’t use dicamba over the root zones of trees and shrubs.

Read and follow the product label every time; the label is the law. Make sure the product is labeled for lawns, or for pastures if that’s where you’re treating, and check grazing restrictions. Applying herbicide for hire in Pennsylvania requires a PA Department of Agriculture pesticide applicator certification, so treating a pasture or a large property is a job for a licensed applicator.

Keeping curly dock from coming back

Dock seed can last a very long time in the soil, so new seedlings will keep appearing for years wherever old plants were allowed to seed. Don’t let them. Mow or cut stalks before they brown, and spot-dig new rosettes when you see them.

Thick turf is your best defense. Mow at about 3 to 3.5 inches, overseed thin areas in early fall, and fix soggy spots so grass grows well there. In pastures, avoid overgrazing, which opens the ground for dock seedlings.

Questions we get about curly dock

Is curly dock poisonous?

It contains oxalates, which can make livestock sick if they eat a lot of it, so don't let it take over pasture. Foragers eat small amounts of the young leaves cooked, but it isn't something to eat in quantity.

Why does curly dock keep growing back after I pull it?

It regrows from the top of the taproot. Snapping off the leaves leaves that part behind. Dig deep enough to remove the top few inches of root.

Does curly dock mean my yard is too wet?

Not always, since it grows on dry ground too, but a cluster of dock in one low spot is often a sign that area stays soggy. Fixing the drainage helps the grass win.

What's the difference between curly dock and broadleaf dock?

Curly dock has narrow leaves with very wavy edges. Broadleaf dock has much wider leaves with a heart-shaped base and only slightly wavy edges.

Weeds taking over a bed, slope or wet spot?

If dock keeps returning in the same soggy low spot, a regrade or a French drain from our crew can fix the wet ground that's giving it the edge. We rebuild beds, regrade and drain wet ground, clear overgrown brush and build patios and walls across Clinton, Lycoming, Centre and Union counties.

Get a free estimate (570) 397-9800

Similar weeds

Broadleaf DockRumex obtusifolius

Red SorrelRumex acetosella

Common BurdockArctium minus

Photos: Wikimedia Commons contributors, credited under each photo (used under their Creative Commons or public-domain licenses).
Further reading: Penn State Extension
Herbicides: always read and follow the product label. Applying pesticides for hire in Pennsylvania requires PA Dept. of Agriculture certification.

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