Broadleaf Knotweed
Polygonum minimum
Last reviewed: August 2026
Toxicity unknown
Broadleaf Knotweed (Polygonum minimum) 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
full sun
Water
low
Size
2"–8" H × 4"–12" W
Bloom
Jun, Jul, Aug, Sep
Native to
CA, CO, ID, MT and 5 more states
Pollinators
bees, beetles
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 445 programs across 44 states, each with a link to the provider and the date we last checked it.
Find rebates in your areaBrowse plants for this ecoregion
Broadleaf knotweed is a low-growing annual that forms small mats with tiny leaves and inconspicuous flowers. This diminutive native plant thrives in sunny, dry conditions and completes its entire life cycle in one growing season.
In an HOA neighborhood
Broadleaf 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.
- Extremely weedy appearance
- Dies back completely as annual
- Too informal for maintained landscapes
Wildlife value
The small flowers attract bees and beetles during the summer months. Seeds may provide food for small birds and ground-dwelling wildlife.
Common questions
- How much sun does Broadleaf Knotweed need?
- Broadleaf Knotweed grows best in full sun conditions.
- When does Broadleaf Knotweed bloom?
- Broadleaf Knotweed blooms in June, July, August, and September.
- Where is Broadleaf Knotweed native?
- Broadleaf Knotweed (Polygonum minimum) is native to CA, CO, ID, MT and 5 more states, per the World Checklist of Vascular Plants (Kew).
- What pollinators does Broadleaf Knotweed attract?
- Broadleaf Knotweed draws bees and beetles.
- Is Broadleaf Knotweed HOA-friendly?
- Broadleaf Knotweed takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.
Native range data from the World Checklist of Vascular Plants (Kew). Pollinator and host plant associations compiled from GBIF, iNaturalist, and published ecological literature.
Ready to grow Broadleaf Knotweed? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.
Not sure where to start? Take the 2-minute yard quiz