🔴 Invasive - Remove
Mile-a-Minute
Persicaria perfoliata
This is an invasive species that harms native ecosystems. It should be removed when found to protect local plant and wildlife habitats.
Persicaria perfoliata
This is an invasive species that harms native ecosystems. It should be removed when found to protect local plant and wildlife habitats.
A fast-growing annual vine with neat triangular leaves, barbed stems, and a small cup-shaped collar where each leaf meets the stem. It can grow six inches a day and forms dense mats over shrubs, streambanks and clearings.
Native to: Eastern Asia (India to Japan)
Arrived in York County, Pennsylvania in the 1930s as a contaminant in nursery stock and has spread through the Mid-Atlantic since, mostly along streams and disturbed edges.
Blankets and shades out whatever it climbs, including tree seedlings that would otherwise close the canopy. Each plant sets hundreds of berries that birds, deer and floodwater carry downstream.
Colour and texture: Pale, almost lime green. Look for the round, saucer-shaped collar that wraps the stem at each node, as though the stem grew up through a small green cup.
Leaves: distinctly triangular, light green, alternate.
Stems: green to reddish, lined with small backward-curving barbs that catch on gloves and clothing.
The tell: a round, saucer-shaped leaf (ocrea) wraps the stem at each node, like the stem is growing through a tiny cup.
Fruit: clusters of iridescent blue berries sit in those cups from late summer.
Berries mid-July–October; seeds can start forming from mid-June.
Tight clusters of hard, iridescent deep-blue berries, each sitting in one of those little cups.
Why it matters: Birds, deer and floodwater all move them, and they stay viable for years. The whole point of pulling by 1 July is to beat this.
Anything with a taproot or shallow roots: garlic mustard, mile-a-minute, seedlings, honeysuckle runners.
Avoid: Do not yank. Speed is what snaps the stem at the root collar and leaves the half that matters behind.
Any plant carrying ripe seed or fruit. Once you start dragging it, you are sowing it.
It can stay on site. Pulled strands can stay. It is an annual with no runners, so a pile with no seed on it is finished.
Bag fruiting plants and put them in the trash. Vines without fruit can be piled off the ground to dry.
Nothing native has that combination of triangular leaves, barbed stems and cup-shaped collars. Tearthumb (Persicaria sagittata) is a native with barbed stems too, but its leaves are narrow arrowheads and it has no cups.
Avoid: Do not carry a fruiting plant across the site to a pile. That walk is how the next patch gets planted.
Before the first cut: No blades needed: it is an annual with shallow roots, so a firm pull takes the whole plant. Get it before the berries in late summer.
Hand-pull before it fruits — aim to be done by July 1. It is an annual with a shallow root system, so a firm pull takes the whole plant. Seeds can start forming from mid-June and ripen from mid-July, and by then the barbs have hardened too. Wear and long sleeves.