Scientific Family
Polygonaceae
Synonyms
Polygonum heterophyllum, Polygonum monspeliense
Other common names
doorweed
knotgrass
wiregrass
yard knotweed
Plant type
Forbs and Subshrubs
Origin
Introduced
Lifecycle
Annual
Height
To 15 inches
Riparian
No
Weedy, prostrate, mat forming plant, branching from a central point, reaching 4 to 80 inches in diameter. Flowers are inconspicuous at leaf axils.
Stems decumbent or prostrate with flowers scattered along the stem in axillary clusters distinguishes this from other Polygonum
sp.
Habitat
Mainly in disturbed areas.
Plant Community
Disturbed Areas
Low elevation
100
High elevation
8500
Flower Characteristics
Flowers are small, 1/16 - 1/8 inch long, in leaf axils.
Flower color
Greenish with white to pink or red margins
Flower shape
Inconspicuous
Tubular
No
First bloom month
March
Last bloom month
October
Flower clusters
None
Leaf and Stem Characteristics
Leaves are lance-shaped to oblong, 1/2 to 2-1/2 inches long and 1/8 to 1/3 inch wide with thin papery sheaths at each node. The wiry stems are prostrate to semi-erect.
Leaf type
Simple
Leaf color
Green
Leaf shape
Narrow
Leaf margin
Smooth
Leaves clasp
No
Leaf hairs
None
Spines
No
Fruit and Seed Characteristics
Contains 1 seed.
Fruit type
Achene
Fruit color
Reddish-brown
Seeds are 3-angled and about 1/16 inch long.