Polygonum perfoliatum (Asiatic tearthumb)

Polygonum perfoliatum L.

Asiatic tearthumb, devil’s tail, mile-a-minute vine, mile-a-minute weed, mile-a-minute knotweed

Kingdom	Plantae	Plants, but not fungi, lichens, or algae
Subkingdom	Tracheobionta	Vascular plants—plants with a “circulatory system” for delivering water and nutrients
Division	Magnoliophyta	Flowering plants, also known as angiosperms
Class	Magnoliopsida	Dicotyledons—plants with two initial seed leaves
Subclass	Caryophyllidae	Cacti, many other succulents, carnivorous plants, and leadworts
Order	Caryophyllales	Includes cacti, carnations, amaranths, ice plants, and many carnivorous plants
Family	Polygonaceae	Knotweed or smartweed family
Genus	Polygonum	Greek poly, “many,” and gonu, “knee,” for the swollen jointed stems
Species	perfoliatum	“Perforated,” because the stem “perforates” the leaves

About plant names...

This Asian vine, introduced to North America in the 1930s, is spreading rapidly, and considered a serious invasive threat. I first encountered this vine on a rainy afternoon at my sister’s home in Phoenix, Maryland. It had engulfed nearly everything else, except for towering black walnut trees, in the wooded area behind her yard. It grows up to six inches per day, and is as effective as oriental bittersweet or kudzu at overwhelming and killing native plants. It occurs almost anywhere there are warm moist or wet open areas: woods, wetlands, roadsides, fields, stream banks, forest edges.

Plants: Vines have reddish stems with backward-pointing hooks that allow it to clamber over other plants.

Leaves: 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.

Flowers: Flowers and fruits emerge from the ocreas. Flowers are white, but inconspicuous.

Fruits: 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.

Edibility: Fruits are edible, eaten fresh. Young leaves and shoots are edible either raw, as salad greens, or cooked.

10/4/2010 · Susan and Raimond’s, Phoenix, Maryland
≈ 5 × 8" (13 × 19 cm)

10/4/2010 · Susan and Raimond’s, Phoenix, Maryland
≈ 4½ × 4½" (11 × 11 cm)

These similar species are most easily distinguished by leaf shape:

	*Polygonum arifolium*	*Polygonum sagittatum*	You are here 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