Prostrate Knotweed
Polygonum aviculare
Last reviewed: August 2026
Toxicity unknown
Prostrate Knotweed (Polygonum aviculare) is not listed by the ASPCA Animal Poison Control Center (opens in new tab) or the other sources we check, so we have no verdict for it either way. Absence from those lists is not a clearance. If your pet shows symptoms after eating any plant, call the ASPCA at (888) 426-4435.
Light
part shade
Water
low
Size
2"–12" H × 6"–24" W
Bloom
Jun, Jul, Aug, Sep
Native alternatives to Prostrate Knotweed
Prostrate Knotweed is not native to the United States. These natives fill a similar role in a planting, matched on bloom season, bloom color and mature size.
Before you buy
Your city may pay you to plant this
Cities and water utilities offer rebates for replacing lawn with native and water-wise plants. We track 450 programs across 44 states, each with a link to the provider and the date we last checked it.
Find rebates in your areaProstrate knotweed is a low-growing annual that forms a spreading mat close to the ground. This hardy plant produces small, inconspicuous flowers from summer through early fall and tolerates poor soils and dry conditions.
In an HOA neighborhood
Prostrate Knotweed takes more care to keep looking intentional in a front yard. Maintenance level: low. Consider it for backyard or mid-zone beds rather than the street edge.
Works well in: backyard only.
- Commonly considered a weed
- Can spread aggressively
- Very informal appearance unsuitable for maintained landscapes
Wildlife value
This plant provides modest wildlife value, offering small seeds for birds and some nectar for small pollinators during its extended bloom period.
Common questions
- How much sun does Prostrate Knotweed need?
- Prostrate Knotweed grows best in part shade conditions.
- When does Prostrate Knotweed bloom?
- Prostrate Knotweed blooms in June, July, August, and September.
- Is Prostrate Knotweed HOA-friendly?
- Prostrate Knotweed takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.
Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
If something looks wrong
Common plant problems, and what to check first
These come up on almost any plant. Each guide lists the likely causes in the order they are worth ruling out, with one thing to check before you act on any of them, and links to the source it came from.
- It is dying right after planting
- Leaves turning yellow
- Wilting even though I watered it
- Brown crispy leaf tips
- Bugs on the plant
Ready to grow Prostrate Knotweed? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.
Planning a bed around it? Start a free plan with this plant
Not sure where to start? Take the 2-minute yard quiz