Knotweed is an herbaceous perennial originally discovered in Virginia and is in the knotweed (Polygonacea) family. It is native to the U.S. along the east coast except for Maine, west toward eastern Texas, south to the Gulf Coast and north to southern Minnesota. The Latin genus name means peach-like and “arrow-shaped” which describes the leaf shape. The specific epithet refers to its Virginia origin. The common name jumpseed refers to the dispersal of the seed. When the mature fruit seed is lightly touched, the tension of the downward bent stem holding the fruit is released and forcefully throws the seed several feet It can grow in full sun but prefers rich, moist to wet, woodland soils in shade to partial shade conditions. They can be found submerged along streams and lakes where the seeds provide food for ducks, micro, and macroinvertebrates. The plant self-seeds and spreads by rhizome and can be propagated by root division and seed. Plants can be 2-3 feet tall with a clumping arching habit. The sparse tiny white to greenish-white flowers bloom on long, slender stems in mid to late summer. Even though the flowers are not showy, they attract butterflies and bees. This native species is often confused with the Asian species Persicaria filifera , but that species has a dark chevron variegation on the upper surface of each leaf. Knotweed can be used in borders, along riverbanks and naturalized in shady woodland sites. It can also be grown in a container to minimize spread. Knotweed is deer and rabbit resistant. Protect from the wind and keep the soil moist, especially in sunny locations. Insects, Diseases, and Other Plant Problems: There are no serious insect or disease problems. Some cultivars may spread aggressively. Can be weedy in a garden setting.
Curated pairwise relationships between this plant and others in the library — who feeds
whom, who competes, who confuses the pests. Green reads as a good pairing, red as one to avoid.
No curated interactions recorded for this species yet.
Full plant profile
Growing Conditions
Plant type
Herbaceous Perennial
Life cycle
Perennial
USDA zones
5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b
Light
Full sun (6 or more hours of direct sunlight a day) | Partial Shade (Direct sunlight only part of the day, 2-6 hours)
Soil texture
High Organic Matter; Loam (Silt); Sand
Soil pH
Acid (<6.0)
Soil drainage
Good Drainage | Moist | Occasionally Wet
Available space
3 feet-6 feet
NC region
Coastal; Mountains; Piedmont
Mature size
Height: 2 ft. 0 in. - 3 ft. 0 in. | Width: 3 ft. 0 in. - 4 ft. 0 in.
Growth rate
Rapid
Maintenance
Low
Canopy layer
4 - Herbaceous (3-15 ft)
Form & Appearance
Habit / form
Arching; Clumping; Erect
Texture
Medium
Leaf color
Green
Leaf type
Simple
Leaf arrangement
Alternate
Leaf shape
Lanceolate; Ovate
Leaf margin
Entire
Leaf feel
Smooth
Leaf size
3-6 inches long, 1-3 inches wide
Hairs present
No
Leaf detail
The leaf is lance-like to oval with a sharp tip. The leaf color is medium green on top and silvery lighter green underneath. Leaves are up to 6 inches long and 3 inches wide.
Flower color
Green; White
Flower form
Raceme
Flower shape
Cup
Flower size
< 1 inch
Flower detail
The white to greenish-white, beady, cup-shaped flowers are 1/8' long with four petal-like sepals and slightly protruding stamens. The inflorescence is a thin 4-16" spike with flowers widely spaced. It blooms July to September.
Bloom time
Summer
Fruit color
Brown/Copper
Fruit type
Achene
Fruit size
< 1 inch long, < 1 inch wide
Fruit detail
The fruit containing one dry seed has a hooked tip that "jumps" off easily when touched.
Stem color
Green
Stem detail
The stem is smooth below the nodes and hairy above. The stem joints are sheathed.
Wildlife & Ecology
Native status
Native
Origin
E. Canada to Mexico
Distribution
In the US, it is found throughout the East. The western border is eastern Texas and then north to eastern Nebraska and southern Minnesota.
Wildlife value
Along streams and lakes, the seeds are eaten by ducks, small birds, and small mammals. The submerged parts provide a habitat for micro and macro invertebrates.
Attracts
Bees; Butterflies; Pollinators
Food & Medicine
Harvest time
Fall; Summer
Fruit type
Achene
Landscape Use
Landscape location
Container; Naturalized Area; Riparian; Woodland
Landscape theme
Butterfly Garden; Pollinator Garden; Shade Garden; Water Garden