How much sun does Pale Knotweed need?

Pale Knotweed grows best in part shade conditions.

When does Pale Knotweed bloom?

Pale Knotweed blooms in June, July, August, and September.

Where is Pale Knotweed native?

Pale Knotweed (Persicaria lapathifolia) is native to AL, AR, AZ, CA and 44 more states, per the World Checklist of Vascular Plants (Kew).

What pollinators does Pale Knotweed attract?

Pale Knotweed draws bees and beetles.

Is Pale Knotweed HOA-friendly?

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

Pale Knotweed

Name: Pollinator Patch
Author: Pollinator Patch

Persicaria lapathifolia

Last reviewed: August 2026

Toxicity unknown

Pale Knotweed (Persicaria lapathifolia) 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

medium

Size

12"–36" H × 6"–24" W

Bloom

Jun, Jul, Aug, Sep

Native to

AL, AR, AZ, CA and 44 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 437 programs across 44 states, each with a link to the provider and the date we last checked it.

Find rebates in your area

Browse plants for this ecoregion

Coast Range Puget Lowland Marine West Coast Forest Northwestern Forested Mountains Sierra Nevada Central California Foothills and Coastal Mountains Central California Valley Southern California Mountains North American Deserts Central Basin and Range Mojave Basin and Range Southern Rockies Arizona/New Mexico Mountains Chihuahuan Deserts High Plains Southwestern Tablelands Central Great Plains Great Plains Cross Timbers Edwards Plateau East Central Texas Plains South Central Plains Ozark Highlands Central Irregular Plains Northwestern Glaciated Plains Northwestern Great Plains Piedmont Northern Glaciated Plains Western Corn Belt Plains Northern Lakes and Forests North Central Hardwood Forests Driftless Area Southeastern Wisconsin Till Plains Central Corn Belt Plains Eastern Corn Belt Plains Southern Michigan/Northern Indiana Drift Plains Huron/Erie Lake Plains Northeastern Highlands Northeastern Coastal Zone Northern Allegheny Plateau Erie Drift Plain Northern Forests Middle Atlantic Coastal Plain Northern Piedmont Southeastern Plains Ridge and Valley Central Appalachians Western Allegheny Plateau Interior Plateau Interior River Valleys and Hills Mississippi Alluvial Plain Mississippi Valley Loess Plains Southern Coastal Plain Madrean Archipelago Sonoran Basin and Range Acadian Plains and Hills Eastern Great Lakes Lowlands Atlantic Coastal Pine Barrens Southern California/Northern Baja Coast

Pale knotweed is an annual wildflower that produces small pink or white flower clusters from summer through fall. This native plant grows in a somewhat sprawling habit and thrives in partially shaded areas with moderate moisture.

In an HOA neighborhood

Pale 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.

Has a weedy, unkempt appearance
Annual habit means gaps in landscape design
Common name includes 'weed' which raises HOA concerns

Wildlife value

The long blooming period from June through September provides nectar for bees and beetles throughout the growing season.

Common questions

How much sun does Pale Knotweed need?: Pale Knotweed grows best in part shade conditions.
When does Pale Knotweed bloom?: Pale Knotweed blooms in June, July, August, and September.
Where is Pale Knotweed native?: Pale Knotweed (Persicaria lapathifolia) is native to AL, AR, AZ, CA and 44 more states, per the World Checklist of Vascular Plants (Kew).
What pollinators does Pale Knotweed attract?: Pale Knotweed draws bees and beetles.
Is Pale Knotweed HOA-friendly?: Pale 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 Pale Knotweed? Add it to your garden in Pollinator Patch to track it and get season-by-season care guidance.

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