Polygonum sagittatum L.

Arrow tearthumb

About plant names...

These North American natives favor wet, marshy ground.

Plants: These plants have hollow vinelike stems up to 3-6' (91-182 cm) long, with squared edges and tiny, backward-pointing prickles. The prickles help the plant attach to surrounding plants as it meanders over them. Stems may be green, pink, or red.

Leaves: Shaped like arrowheads, attached via short ⅜" (1 cm) stems. The base of each leaf is clasping—it tends to wrap around the stem. Leaf edges also have tiny prickles.

Flowers: Flowerheads are less than ⅜" (1 cm) in diameter, white to pink in color. Each rounded flowerhead consists of 5-20 individual flowers at the end of a long stem, which emerges from a leaf node.

Fruits: Small nutlets, brown to black.

8/18/2010 · J. Harry Rich Woods, off Nod Rd., Groton, Mass­a­chu­setts
≈ 6 × 4" (15 × 10 cm)

8/17/2020 · Otter Brook Preserve, Harpswell, Maine
≈ 7 × 4½" (18 × 12 cm)

These similar species are most easily distinguished by leaf shape:

	Polygonum arifolium	You are here Polygonum sagittatum	Polygonum perfoliatum
Common Name	halberd-leaved tearthumb	arrow tearthumb	Asiatic tearthumb
Plant	Vine has weak stems that are green, pink or red, with many tiny backward-pointing barbs, 24-48" (60-121 cm) long	Stems 3-6' (91-182 cm) long, green, pink, or red, hollow, vinelike, with squared edges and tiny, backward-pointing prickles.	Vines have reddish stems with backward-pointing hooks that allow it to clamber over other plants.
Flowers	Flowerheads are less than ⅜" (1 cm) in diameter, white to light pink, with 5-20 individual flowers at the end of a long stem	Flowerheads are less than ⅜" (1 cm) in diameter, white to pink in color. Each rounded flowerhead consists of 5-20 individual flowers at the end of a long stem.	Flowers and fruits emerge from the ocreas. Flowers are white, but inconspicuous.
Leaves	Leaves are shaped like arrowheads, except that the backward-pointing barbs point outward (technically, "hastate"). Leaves are hairy, 4-4½" (10-11 cm) long	Shaped like narrow arrowheads, attached via short ⅜" (1 cm) stems. The base of each leaf tends to wrap around the stem. Leaf edges also have tiny prickles.	Mile-a-minute vine has leaves that are almost perfect triangles, small curved barbs along its stems, and saucer-shaped leaves (ocreas) at its stem nodes. Although ocreas are present in all Polygonums, they usually take the form of a fibrous sheath wrapped tightly around the plant stem.
Fruit	Seeds are rounded reddish-brown nutlets about ⅛" (3.2 mm) around	Small nutlets, brown to black.	Tightly packed clusters of 10-30 lobed metallic blue fruits, each about ⅛-¼" (3.2-6.3 mm) around. Each lobe or segment contains a single glossy, black or reddish black seed.
Range/ Zones
Habitats	Marshes, swamps, wet meadows	Wet, marshy ground	Almost anywhere there are warm moist or wet open areas: woods, wetlands, roadsides, fields, stream banks, forest edges.
Type	Wild	Wild	Wild
Occurrence	Common	Common	Invasive

Online References:

Missouriplants.com

The Connecticut Botanical Society's Connecticut wildflowers site

The University of Wisconsin's Robert W. Freckmann Herbarium

The Virginia Tech Weed Identification Guide

The Lady Bird Johnson Wildflower Center

9/11/2013 · Nashua River Rail Trail, Groton Center, Groton, Mass­a­chu­setts
≈ 5 × 4½" (13 × 12 cm)

8/18/2010 · J. Harry Rich Woods, off Nod Rd., Groton, Mass­a­chu­setts
≈ 5 × 3½" (13 × 9.2 cm)

8/4/2010 · Nashua River Rail Trail, Groton Center, Groton, Mass­a­chu­setts
≈ 11 × 7" (27 × 18 cm)

8/17/2020 · Otter Brook Preserve, Harpswell, Maine
≈ 10 × 6" (24 × 16 cm)

7/20/2021 · Otter Brook, Harpswell, Maine
≈ 6 × 4" (16 × 10 cm)

9/11/2010 · Nashua River Rail Trail, Groton Center, Groton, Mass­a­chu­setts
≈ 6 × 4" (15 × 10 cm)

8/18/2010 · J. Harry Rich Woods, off Nod Rd., Groton, Mass­a­chu­setts
≈ 3 × 3" (7.6 × 7.4 cm)

8/18/2010 · J. Harry Rich Woods, off Nod Rd., Groton, Mass­a­chu­setts
≈ 4½ × 3" (11 × 7.9 cm)

8/15/2021 · Bass Falls Preserve, Alna, Maine
≈ 2½ × 2½" (6.6 × 6.7 cm)

8/18/2010 · J. Harry Rich Woods, off Nod Rd., Groton, Mass­a­chu­setts
≈ 5 × 3½" (13 × 9.2 cm)

8/15/2021 · Bass Falls Preserve, Alna, Maine
≈ 3½ × 6" (9.4 × 14 cm)

Polygonum sagittatum description by Thomas H. Kent, last updated 8 Sep 2021.

© FloraFinder.org. All rights reserved.

8/15/2021 · Bass Falls Preserve, Alna, Maine
≈ 4 × 4" (11 × 10 cm)

7/20/2021 · Otter Brook, Harpswell, Maine
≈ 2 × 3" (5.7 × 8 cm)

9/14/2013 · Whitewater Rafting Trip, Barryville to Pond Eddy Leg, Delaware River, Barryville, Penn­syl­vania
≈ 5 × 3½" (13 × 8.7 cm)

9/11/2010 · Nashua River Rail Trail, Groton Center, Groton, Mass­a­chu­setts
≈ 7 × 4½" (17 × 11 cm)

9/11/2010 · Nashua River Rail Trail, Groton Center, Groton, Mass­a­chu­setts
≈ 6 × 4" (15 × 10 cm)

8/15/2021 · Bass Falls Preserve, Alna, Maine
≈ 4½ × 2½" (11 × 7.2 cm)

9/14/2013 · Whitewater Rafting Trip, Barryville to Pond Eddy Leg, Delaware River, Barryville, Penn­syl­vania
≈ 5 × 3½" (13 × 8.7 cm)

8/15/2021 · Bass Falls Preserve, Alna, Maine
≈ 4½ × 3½" (11 × 9.4 cm)

9/11/2010 · Nashua River Rail Trail, Groton Center, Groton, Mass­a­chu­setts
≈ 5 × 4" (13 × 10 cm)

8/28/2021 · Otter Brook Preserve, Harpswell, Maine
≈ 2 × 2" (5.7 × 5.3 cm)

Range:

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