Invasive plant
Mile-a-minute weed
Persicaria perfoliata
Mile-a-minute weed identification: triangular leaves, a saucer-shaped sheath and backward barbs on the stem. Learn how to stop this annual vine before seed set.
Published Last reviewed
Mile-a-minute weed is an annual vine with triangular leaves, a circular sheath around the stem and tiny backward barbs. It can cover a shrub quickly, then die at frost and return from seed. The first decision is whether you can get rid of it before seed forms in early summer.
What does mile-a-minute weed look like?
Look for a light green leaf shaped like an equilateral triangle or arrowhead, 1 to 3 inches wide. Turn the leaf over and you may see small hooked barbs along the central vein and the leaf stalk. The stem is thin, angular and often reddish, and it is covered with the same tiny backward-pointing barbs.
The giveaway is the ocrea: a round, saucer-shaped leafy structure that completely encircles the stem at the base of each leaf stalk. In late summer, the vine makes metallic blue or purple berry-like fruit about 1/4 inch across. The pale green flowers are easy to miss.
How to identify mile-a-minute weed
The combination is what settles it: triangle leaf, circular ocrea, backward barbs. Several native plants are called tearthumbs, so do not identify the vine from the leaf shape alone. Check the sheath and the barbs too.
The vine is often found on forest edges, stream banks, roadsides, wetlands and other open, disturbed ground. It prefers full sun but can tolerate some shade. It dies at first frost, leaving a tangle of dead stems that can stay over shrubs and seedlings through winter.
Why mile-a-minute weed spreads
Mile-a-minute is a prolific seed producer. Birds, deer and small mammals eat the fruit and move the seed. The fruit can float for up to nine days, so water moves it downstream. Seed also moves in contaminated soil on equipment and boots.
Penn State Extension says seed can remain viable for at least six years. University of Connecticut Extension puts the seedbank at six years or more and says reducing it takes at least three to five years of consistent work.
How to get rid of mile-a-minute weed
| Your situation | First move | What to watch |
|---|---|---|
| A small patch, before seed forms | Pull the vines by hand, wearing long sleeves and leather gloves. | Before June, pulled vines can dry on site. After flowering, bag them because green fruit can still ripen. |
| A larger patch, before July 1 | Cut at ground level with a string trimmer or mower, then repeat. | The vine regrows from stem nodes. Cutting once will not clear it. |
| A patch with seed | Bag the vines and fruit, then trash them. | Do not compost fruit or seed, and clean tools before leaving. |
| A site near water | Stop and check the label before buying an herbicide. | Use only an aquatic-labeled product, and do not spray the water itself. |
A biological control weevil feeds only on mile-a-minute and can stunt it, but Penn State Extension says it does not eradicate the vine. It is not a quick homeowner fix.
When to treat mile-a-minute weed
| Time of year | What the vine is doing | What to do |
|---|---|---|
| Late February to mid-March | Seed is in the soil, waiting to germinate. | Apply a preemergence product by mid-March, two to three weeks before germination. |
| April | Seedlings emerge. | Pull small patches early, before the barbs harden. |
| May | Vines are growing fast. | Postemergence treatment can begin. Pull or cut before seed forms. |
| June | Vines are still growing, and seed can start forming by mid-June. | This is the last practical window. Finish control before July 1. |
| July and August | Seed is present on many plants. | Pull and bag what you can. Do not leave fruit on site. |
| September and October | Vines are nearing the end of the season. | Remove seed-bearing material and plan next year’s preemergence timing. |
| Winter | Dead stems persist, but the seed is in the soil. | Map the patch and watch for seedlings in spring. |
Is mile-a-minute weed regulated in your state?
| State | Status | What it means for a homeowner |
|---|---|---|
| Pennsylvania | Noxious, Class B | It cannot be sold, transported, planted or propagated. Existing patches do not have to be removed, but control is encouraged. |
| New York | Prohibited | It cannot be sold, imported, purchased, transported, introduced or propagated. |
| Virginia | Noxious, Tier 3 | It is present and eradication is not feasible. Moving a listed noxious weed requires a valid certificate or permit. |
| Ohio | Prohibited noxious weed | State law requires management on public and private property, and the invasive plant list bans sale and spread. |
| Wisconsin | Prohibited | It cannot be transported, possessed, transferred or introduced without a permit, and control is required. |
Check your state’s current list before you move plants, soil or equipment. The Pennsylvania and Virginia pages have the state contacts.
What to do this week
- Check a leaf for the triangle shape and turn it over to look for barbs.
- Look for the circular ocrea around the stem. That is the trait that separates it from other tearthumbs.
- If the patch is small, pull it now with gloves and long sleeves.
- If seed is already present, bag the vines and fruit. Do not compost them.
- Put the July 1 deadline on the calendar. After that, you are managing seed, not preventing it.
For the wider seasonal plan, see when to treat invasive plants and how to get rid of invasive plants without chemicals. The disposal guide explains how to bag seed-bearing material. More profiles are listed under invasive plants, and image credits are on the image credits page.
Identification
Look for the combination of characters below. A single feature is rarely enough, especially when a native look-alike is present.
- Growth habit
- A trailing, herbaceous annual vine that can spread 20 to 30 feet over other plants. In peak growth it can put on up to 6 inches in a day. It dies each fall and returns from seed in spring.
- Leaves
- Alternate, light green and shaped like an equilateral triangle or arrowhead, 1 to 3 inches wide. Small hooked barbs grow along the underside of the central vein and the leaf stalk.
- Stems and sheath
- Thin, angular stems, often reddish, covered with tiny backward-pointing barbs. A round, saucer-shaped leafy structure called an ocrea completely encircles the stem at the base of each leaf stalk.
- Flowers and fruit
- The pale green flowers are easy to miss. In late summer the vine makes metallic blue or purple berry-like fruit about 1/4 inch across, in a cluster at the vine's tips. Each fruit contains a single glossy black or reddish-black seed.
- Winter
- The vines die at first frost, but the dead, tangled stems can persist through winter over shrubs and tree seedlings. Seed remains alive in the soil for at least six years.
Look-alikes
-
Native tearthumbs
Polygonum and Persicaria species
Several native plants are also called tearthumbs. Check the equilateral triangle leaf, the circular ocrea and the dense backward barbs together. One trait alone is not enough.
Range and status
Native range: East Asia and India
Regulatory status by state
-
pennsylvania Noxious weed
Mile-a-minute weed is a Class B noxious weed on the Pennsylvania Department of Agriculture list. Class B means it is widely established and cannot feasibly be eradicated. Noxious weeds cannot be sold, transported, planted or otherwise propagated in the state.
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new-york Prohibited
Mile-a-minute weed is prohibited under 6 NYCRR Part 575. Prohibited plants cannot be sold, imported, purchased, transported, introduced or propagated in New York.
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virginia Noxious weed
Mile-a-minute weed is a Tier 3 noxious weed in Virginia under 2VAC5-317-20. Tier 3 plants are present, spread can be slowed by movement restrictions, and eradication is not feasible. Moving a listed noxious weed requires a valid certificate or permit.
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ohio Noxious weed
Mile-a-minute weed is a prohibited noxious weed under OAC 901:5-37-01, which requires management on public and private property. It is also on Ohio's invasive plant list under OAC 901:5-30-01.
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wisconsin Prohibited
Wisconsin classifies mile-a-minute vine as Prohibited under NR 40. Prohibited species cannot be transported, possessed, transferred or introduced without a permit, and control is required.
Why it matters
Mile-a-minute weed grows over shrubs, tree seedlings and other plants and forms a dense mat that blocks light. Plants underneath can be shaded out, weighed down or broken. The vine produces many seeds, birds and mammals eat the fruit, and the seed can float for days in moving water. A single missed plant can keep the patch going for years.
Management
Control before July 1
Timing: Before July 1, and earlier if seed is already forming.
Penn State Extension says to complete control before July 1 to prevent seed production. University of Connecticut Extension says seed production can begin as early as mid-June. After seed is present, pull the vines, bag them and destroy the material rather than leaving it on site.
Pull small patches
Timing: June through the first frost, every three weeks.
Wear long sleeves and leather gloves; the barbs get sharper as the plant matures. Before June, when seed is not yet present, pulled vines can be left on site to dry. After flowering begins, bag the vines because green fruit can keep ripening after the plant is pulled.
Cut repeatedly
Cutting at ground level with a string trimmer or mower can keep growth down and prevent fruit set, but the vine will regrow from stem nodes. Repeated cutting is a schedule, not a one-time job. Clean equipment after working in an area with seed.
Use preemergence herbicide before germination
Timing: Late February to mid-March.
Penn State Extension names prodiamine and pendimethalin as selective preemergence options and says to apply them two to three weeks before germination, generally by mid-March. Adding a low rate of imazapic or sulfometuron can make the timing more flexible. Follow the product label; the label is the law.
Treat emerged vines in late spring
Timing: May and June.
Penn State Extension names water-based triclopyr for postemergence control where grasses should be left intact, and a glyphosate plus triclopyr mix for spot treatments in mixed vegetation. It also lists imazapic and sulfometuron as pre- and postemergence options. Near water, use only an aquatic-labeled product. Follow the product label; the label is the law.
Plan for the seedbank
Seed remains viable for at least six years, so one season will not clear a site. A biological control weevil can stunt the vine, but Penn State Extension says it does not eradicate it. Monitor for new seedlings and replant bare ground with native vegetation.
Sources
Facts on this page were checked against the sources below. Each link shows the date the source was accessed.
- Mile-A-Minute Weed — USDA National Invasive Species Information Center Accessed November 3, 2026
- Mile-a-Minute — Penn State Extension Accessed November 3, 2026
- Invasive Plant Factsheet: Mile-a-minute — University of Connecticut Integrated Pest Management Accessed November 3, 2026
- Mile-a-Minute — University of Maryland Extension Accessed November 3, 2026
- Persicaria perfoliata (L.) H. Gross (mile-a-minute weed) — USDA NRCS PLANTS Database Accessed November 3, 2026
- Controlled Plant & Noxious Weeds Lists — Pennsylvania Department of Agriculture Accessed November 3, 2026
- Invasive Species Regulations — New York State Department of Environmental Conservation Accessed November 3, 2026
- 2VAC5-317-20. Tier 1, Tier 2, and Tier 3 noxious weeds — Virginia Administrative Code Accessed November 3, 2026
- Prohibited Noxious Weeds — Ohio Department of Agriculture Accessed November 3, 2026
- Regulated Species — Wisconsin Department of Natural Resources Accessed November 3, 2026
Related pages
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Spring Invasive Plants Checklist: What to Look For in March, April, May and June
Spring invasive plants checklist: what to look for and act on each month from March through June, with links to species and removal guides.