How much sun does Denseflower Knotweed need?

Denseflower Knotweed grows best in part sun conditions.

When does Denseflower Knotweed bloom?

Denseflower Knotweed blooms in July, August, and September.

Where is Denseflower Knotweed native?

Denseflower Knotweed (Persicaria glabra) is native to AL, AR, DE, FL and 13 more states, per vouchered herbarium specimen records and regional native plant society lists.

What pollinators does Denseflower Knotweed attract?

Denseflower Knotweed draws bees and beetles.

Is Denseflower Knotweed HOA-friendly?

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

Denseflower Knotweed

Name: Pollinator Patch
Author: Pollinator Patch

Persicaria glabra

Last reviewed: September 2026

Toxicity unknown

Denseflower Knotweed (Persicaria glabra) 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 sun

Water

medium

Size

12"–36" H × 6"–18" W

Bloom

Jul, Aug, Sep

Native to

AL, AR, DE, FL and 13 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 452 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

Cross Timbers Texas Blackland Prairies East Central Texas Plains Western Gulf Coastal Plain South Central Plains Piedmont Middle Atlantic Coastal Plain Southeastern Plains Ridge and Valley Mississippi Alluvial Plain Mississippi Valley Loess Plains Southern Coastal Plain Atlantic Coastal Pine Barrens

Persicaria glabra is a native perennial that produces dense clusters of small white to pink flowers from summer through early fall. This compact plant forms neat clumps and thrives in partial sun with average moisture conditions.

In an HOA neighborhood

Denseflower 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.

Name contains 'knotweed' which has negative associations
May be confused with invasive knotweed species
Relatively unknown plant may raise HOA concerns

Wildlife value

The dense flower clusters attract bees and beetles during the long blooming period from July through September.

Common questions

How much sun does Denseflower Knotweed need?: Denseflower Knotweed grows best in part sun conditions.
When does Denseflower Knotweed bloom?: Denseflower Knotweed blooms in July, August, and September.
Where is Denseflower Knotweed native?: Denseflower Knotweed (Persicaria glabra) is native to AL, AR, DE, FL and 13 more states, per vouchered herbarium specimen records and regional native plant society lists.
What pollinators does Denseflower Knotweed attract?: Denseflower Knotweed draws bees and beetles.
Is Denseflower Knotweed HOA-friendly?: Denseflower 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 vouchered herbarium specimen records and regional native plant society lists. 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.

See all plant problem guides

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