Persicaria sagittata (arrow-leaved tearthumb)

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Persicaria, Genus, sagittata, Species,

Genus & species

arrow-leaved tearthumb

Polygonaceae

Eastern North America and eastern Asia

Attracts Pollinators Attracts Butterflies

SunFull Sun – Part Shade

WaterHigh

Overview

Persicaria sagittata, arrow-leaved tearthumb, is a sprawling annual in the knotweed family with weak, four-angled stems 2-6 feet (60-180 cm) long that lean on other plants for support. The stems and leaf stalks are lined with tiny, downward-pointing prickles that catch on skin and clothing, which gives the plant its common name. The arrow-shaped leaves are 1-3 inches (2.5-7.5 cm) long, with backward-pointing basal lobes. From summer into fall it bears small, tight clusters of pink to white flowers about 0.1 inch (3 mm) across at the stem tips. It grows in wet meadows, marshes, ditches, and the muddy edges of ponds and streams across eastern North America and eastern Asia. As a wetland annual it dies after setting seed and returns from a large seed bank, sometimes forming dense tangles. The clinging, prickly stems can be a nuisance to people moving through wet ground. P. sagittata is grown in wetland restorations and rain gardens and as cover and seed for wetland wildlife.

Native Range

Persicaria sagittata is native to eastern North America, from eastern Canada south to Florida and west to the Great Plains, and also to eastern Asia. It grows in marshes, wet meadows, swamps, ditches, and the margins of ponds and slow streams. It is common in low, wet ground throughout its range.

Suggested Uses

Arrow-leaved tearthumb is grown in wetland restorations, rain gardens, and pond and ditch margins for erosion control and wildlife habitat. Its seeds feed waterfowl, marsh birds, and small mammals, and the tangled stems give cover. It grows on consistently wet, sunny sites.

How to Identify

Recognize arrow-leaved tearthumb by its weak, sprawling, square stems armed with rows of tiny, hooked, downward-pointing prickles that scratch the skin. The arrow-shaped leaves have two backward-pointing lobes at the base. Small, dense heads of pink to white flowers appear at the stem tips in summer and fall. The combination of arrow-shaped leaves and prickly, clinging stems separates it from other smartweeds.

Appearance

Size & Dimensions

Height2' - 6'

Width/Spread1' - 3'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~12 weeks

Flowers: July–October

Summer Fall

Flowering occurs from midsummer into fall, roughly July through October. The small pink to white flower clusters open over a long period at the stem tips. Three-sided seeds ripen afterward and drop into the wet soil.

Detailed Descriptions

Flower Description

Pink to white

Foliage Description

Green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-12 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 - 7.5 (Acidic to alkaline)

3579

Soil Types

clay loam silt

Drainagewet

Water & Climate

Water Needs

High

Care & Maintenance

Care Guide

Grow arrow-leaved tearthumb in full sun to part shade in wet to saturated soil, including the muddy margins of ponds, ditches, and marshes. It tolerates standing water and seasonal flooding and grows in clay, loam, and mucky soils. As an annual it completes its cycle in one season and depends on reseeding, so it returns each year where soil stays moist. It needs no fertilizer and little care in a wet setting but declines quickly on dry ground. The prickly stems make handling unpleasant. It has few pests and can spread densely from its seed bank.

Pruning

No routine pruning is needed for this annual. Cutting or pulling plants before seed ripens limits spread where it is unwanted. Spent plants die back on their own at frost.

Toxicity

Non-toxic

Related Persicaria species