Pale Smartweed

Kendall County (IL) Forest Preserve District

Pale Smartweed (Curlytop Knotweed)
Persicaria lapathifolia [C-value 0]
Knotweed family (Polygonaceae)
Blooms July - September

The native Pale Smartweed is common in our wet areas. It prefers full sun or partial sun and wet to slightly moist fertile soil with organic matter. Habitats include marshy areas, edges of streams and drainage canals, mudflats, roadside ditches and moist weedy meadows. It is a summer annual, 2½–4' tall, branching occasionally with stems that are light green and hairless. The alternate leaves are up to 8" long and 2" across, lance-shaped, smooth and untoothed with short petioles having a membranous sheath clasping the stem. Upper stems terminate in 1 or 2 racemes of densely crowed flowers. The racemes are 2-8" long, often drooping. Each flower is about 1/8" across, usually white, greenish white or light pink.

Pale Smartweed at Rose Hill Subdivision pond September 11, 2013

Pale Smartweed at Baker Woods Forest Preserve August 28, 2012

Pale Smartweed at Subat Forest Preserve September 11, 2013

Pale Smartweed at Yorkville Riverside Park August 24, 2015

The bitter taste of Smartweed leaves is “smarting” and the plant was sometimes called "Water-Pepper”. It was used as an antiseptic and as a stimulant for “pains of the joints”.

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