Pale smartweed

Persicaria lapathifolia · Aquatic plants

Whole plant · Photo: Roberto Daniel Avila / CC BY

NativeShoreline

Also called Polygonum lapathifolium, Curlytop knotweed, Willow weed

How to identify Pale smartweed

Annual 1 to 4 feet tall with swollen, jointed stems
Papery sheaths at each leaf joint
Slender, arching or drooping spikes of pale pink to greenish white flowers
Lance shaped leaves, sometimes with a dark blotch in the middle

Similar plants

Lady's thumb has short, upright pink spikes and fringed sheaths; water smartweed is a perennial with dense upright spikes and often floating leaves.

Growth profile

Growing season	Sprouts on exposed mud in late spring, flowers from July until frost and dies with the first hard frost.
Starts growing	Warm, exposed mud in late spring
Light	Full sun
Depth	Wet mud to a few inches of water
How it spreads	Seeds
Habitat	Exposed mud of pond and reservoir drawdowns, ditch banks, wet fields and shorelines.

Why it matters in a lake

One of the first plants to cover exposed mud when a pond is drawn down. The seeds are a valuable duck food, so it is often encouraged in managed wetlands.