KNOTWEED
Polygonum aviculare
BUCKWHEAT FAMILY (Polygonaceae)
Identification
- Flowering time - June, July, August, September, October
- Common in disturbed sites at FF and NW
- Low growing plant often forming large mats
- Stems with swollen area (knot) covered by a papery sheath
- Tiny flowers, usually closed or only partly open except on very sunny days
This Eurasian import, a prostrate mat-forming annual, often with erect terminal stems, thrives in our most inhospitable sites (C,D). Stems are swollen and have papery, sometimes reddish sheaths at the nodes which mark the junction of the leaf and stem (E). Elliptical, bluish-green alternate leaves are less than 1 inch long and 1/4 inch wide (A). Tiny, almost invisible whitish flowers, often with pink margins, arise at the junction of the leaf and stem (B). Flowers are often closed or partly so, opening only on very bright sunny days.
Common in disturbed, packed soil including roadsides and parking lots at Neale Woods and Fontenelle Forest. Flowering occurs from June through October.
The swollen stems with papery sheaths at the leaf nodes separate the knotweeds from other plants sharing inhospitable sites like the prostrate Euphorbia species. (see Spotted Spurge, Euphorbia maculata)
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