Mile-a-minute weed (Persicaria perfoliata)

Synonyms: Polygonum perfoliatum

Common Names: Asiatic tearthumb, Chinese tearthumb

Description: Introduced in the 1930s.

Habit: Herbaceous annual; fast-growing, trailing vine; covers and eventually kills its host vegetation; variable height.

Leaves: Simple, alternate, triangular, light green-blue in color, barbs on the underside.

Stems: Reddish; narrow; covered with barbs that attach to other plants; circular, cup-shaped, leafy appendages (ocreas) that surround the stem; up to 7 m long.

Flowers: Small, unnoticeable, white in color, closed, emerge from ocreas along the stem; blooms in June.

Fruit and seeds: Metallic, greenish-white, turning dark blue in fall, pea-sized, clumped berries.

Habitat: Native to East Asia. Relatively shade intolerant; found on moist sites in open disturbed areas, woodland edges, wetlands, stream banks.

Reproduction: Mainly through self-pollinated seed production.

Similar species: Mile-a-minute weed may resemble native Halberdleaf tearthumb (Polygonum arifolium); Arrowleaf tearthumb (P. sagittatum) but its leafy, expanded ocreas and pea-sized blue fruits are distinctive.

Monitoring and rapid response: Monitor roadsides, thickets, stream banks, meadows, woodland edges, clear-cuts and utility right-of-ways; most easily recognized in late March and early April as it germinates early in the season. For small infestations, hand-pulling, mowing and cultivating may provide effective control by preventing flowering and seed production; remove and dry vines before disposal; wear heavy gloves; foliar herbicide application provides effective control, as the leaves have a waxy coating, a surfactant will help the herbicide adhere. As this species is not yet recorded in Michigan, it is important to document new occurrences. Please obtain flowering or fruiting specimens and submit to: Anton Reznicek, Curator (Vascular Plants), University of Michigan Herbarium, 3600 Varsity Drive, Ann Arbor, MI 48108-2287.

Credits: The Michigan Natural Features Inventory (MNFI) has partnered with MISIN to provide the information in this fact sheet. Species images and/or information were used with permission from "A Field Identification Guide to Invasive Plants in Michigan's Natural Communities" and "A Field Guide to Invasive Plants of Aquatic and Wetland Habitats for Michigan.

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