How much sun does Douglas's Knotweed need?

Douglas's Knotweed grows best in full sun conditions.

When does Douglas's Knotweed bloom?

Douglas's Knotweed blooms in June, July, and August.

Where is Douglas's Knotweed native?

Douglas's Knotweed (Polygonum douglasii) is native to AZ, CA, CO, IA and 16 more states, per the World Checklist of Vascular Plants (Kew).

What pollinators does Douglas's Knotweed attract?

Douglas's Knotweed draws bees and beetles.

Is Douglas's Knotweed HOA-friendly?

Douglas's Knotweed takes more care to look intentional in a front yard. Consider it for backyard or mid-zone beds rather than the street edge.

Douglas's Knotweed

Name: Pollinator Patch
Author: Pollinator Patch

Polygonum douglasii

Last reviewed: August 2026

Toxicity unknown

Douglas's Knotweed (Polygonum douglasii) 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

4"–16" H × 2"–8" W

Bloom

Jun, Jul, Aug

Native to

AZ, CA, CO, IA and 16 more states

Pollinators

bees, beetles

Before you buy

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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.

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Browse plants for this ecoregion

Coast Range Puget Lowland Marine West Coast Forest Northwestern Forested Mountains Sierra Nevada Central California Foothills and Coastal Mountains Southern California Mountains North American Deserts Central Basin and Range Southern Rockies Arizona/New Mexico Mountains High Plains Southwestern Tablelands Northwestern Glaciated Plains Northwestern Great Plains

Douglas's knotweed is a low-growing annual wildflower that forms small mats close to the ground. It produces tiny white or pink flowers during summer months and thrives in sunny, dry conditions with minimal water requirements.

In an HOA neighborhood

Douglas's 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.

Very small stature may appear weedy
Annual lifecycle creates gaps when plant dies
Common name includes 'weed' which raises HOA concerns

Wildlife value

This plant provides nectar for native bees and serves as a food source for beetles during its summer blooming period.

Common questions

How much sun does Douglas's Knotweed need?: Douglas's Knotweed grows best in full sun conditions.
When does Douglas's Knotweed bloom?: Douglas's Knotweed blooms in June, July, and August.
Where is Douglas's Knotweed native?: Douglas's Knotweed (Polygonum douglasii) is native to AZ, CA, CO, IA and 16 more states, per the World Checklist of Vascular Plants (Kew).
What pollinators does Douglas's Knotweed attract?: Douglas's Knotweed draws bees and beetles.
Is Douglas's Knotweed HOA-friendly?: Douglas's 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 Douglas's Knotweed? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.

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