Scientific Name: Polygonum aviculare

Common Name: prostrate knotweed

Synonyms: Polygonum aviculare var. vegetum, Polygonum heterophyllum, Polygonum monspeliense

Habit: Emerges in the early spring, but can continue to emerge in the late spring and summer as well. Flowering occurs from June through November.

Leaves: Leaves begin looking almost grass-like and have a waxy whitish coating. Mature leaves are broad leaves that are narrowed at the base, ranging from lanceolate, elliptic to oblong shapes. The petioles are short and have a conspicuous ocrea sheathing the stem at the leaf base.

Identifying Characteristics: The plant forms mats or clusters of dead mesh-like stems that remain throughout the winter.

Flower Seed Head: Flowers appear in 1 to 5 axillary clusters. They are small white to green with some pinkish margins, lacking petals.

Seed Fruit: The friut contains the seed (achene). Achense are about 2 to 3 mm long teardrop-shaped with dark reddish brown to black coloring.

Where Found: Prostrate knotweed can infest turfgrass, nursery crops, landscapes, and areas that is damaged by traffic such as pathways. Grows well in stressed areas.

  • Life cycle: summer annual

  • Milky sap: Not Present

  • Plant type: Herb

  • Plant family: Polygonaceae

  • Leaf arrangement: alternate

  • Leaf shape: oval

  • Ochrea: Present

  • Flower color: pink; white

  • Stem: round or oval

  • Leaf hairs: no hairs

  • Root structure: taproot

  • Leaf stalk: shorter than leaf