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Prostrate knotweed
Also known as: Doorweed , Wiregrass, Birdgrass, Pigweed
Prostrate knotweed (Polygonum aviculare) is a low-growing species that can root practically anywhere. It produces many small white flowers each summer and produces plenty of seeds that can survive for years. Its seeds can lay dormant in soils, and once they see sunlight, they will start to germinate. Because it grows so dwarf, mowing is not effective in removing it.
Scientific classification
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Weeds
Weed or not
Herb
Plant Type
Summer, Early fall, Mid fall
Bloom Time
Mid summer, Early fall
Harvest Time
10 cm to 40 cm
Plant Height
60 cm to 90 cm
Spread
Green
Leaf Color
2 mm to 5 mm
Flower Size
Brown
Fruit Color
White, Green, Red
Flower Color
Green
Stem Color
Winter dormancy
Dormancy
Deciduous
Leaf type
20 - 35 ℃
Ideal Temperature

Images of Prostrate knotweed

Distribution of Prostrate knotweed

Distribution Map
Prostrate knotweed is native to the most of entire temperate northern hemisphere, its range stretching across the whole of Eurasia, America, parts of Africa. It is usually found in grassland biomes with disturbed soil.
Native
Cultivated
Invasive
Introduced
No species reported
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Habitat
Waste places, roadsides, railway embankments, coast, garden
Hemisphere Trend Curve

Culture

Symbolism
Restoration
Interesting Facts
This plant was found in Philadelphia around 1910. It is a kind of rice field weed that is hard to remove because of its strong viability in wetlands, river banks, grasslands, moors and mudflats.
Name Story
Prostrate knotweed: The stem is very special because it looks like bamboo with multiple nodes in a section. This may be the reason why this genus is called knotweed. Since the plant grows in a prostrate position, it is called prostrate knotweed.
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Toxicity

Consuming large quantities of prostrate knotweed leaves, which contain oxalic acid, can cause mineral deficiencies. People with rheumatism, arthritis, gout, kidney stones, and hyperacidity should avoid prostrate knotweed to prevent exacerbation of these conditions. There's a potential for photosensitivity, though no reports exist for this species.
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Weed Control

Prostrate knotweed has spread as a weed to almost all temperate locations from its native habitat of Eurasia. It is considered invasive or an agricultural weed in 3 states. It readily establishes a persistent seedbank, with individual plants able to produce thousands of seeds that can last several years. Prostrate knotweed has been used as groundcover and cultivated as a dye; it has also been found to suppress other weeds and kill potato pathogens. However, it can also have synergistic effects or acts as an alternative host for crop pathogens and pests. Mowing is generally ineffective due to its matting growth pattern, but a combination of herbicide and other techniques including tilling, polarization, undersowing, and plowing can effectively control prostrate knotweed.
How to Control It
The best season for removing prostrate knotweed or prostrate knotweed is spring. It's ideal to remove this plant before it reaches the flowering stage to prevent it from spreading seeds.
  1. Hand pulling: Put on a pair of gloves to protect your hands. Grasp the knotweed close to the ground and firmly pull it out, being careful to remove all the roots. Doing it after rainfall can make this task easier as wet soil loosens the root grip. Dispose of the plant in a garden waste bag.
  2. Smothering: Cover the area where prostrate knotweed is growing with a thick layer of newspaper or cardboard, and then add a layer of mulch on top. This method works by denying the plant light and air, causing it to die off.
  3. Planting competition: Simultaneously planting faster-growing, more competitive plants can help limit the space for prostrate knotweed to grow. Choose species that are native to your area and that grow thickly to limit the knotweed's access to light, water, and space.
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Quickly Identify Prostrate knotweed

1
Sprawling habit with stems up to 3 feet (91 cm) long.
2
Oval, pointed leaves with a smooth texture and alternate arrangement.
3
Tiny, inconspicuous flowers with greenish-white hue in leaf nodes.
4
Small, 3-angled hard achene fruit, brown to reddish-brown in color.
5
Stems matted and wiry, branching frequently for a dense appearance.
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RELATED: How to identify Prostrate knotweed

Care Guide for Prostrate knotweed

Every week
Water
Full sun
Sunlight
20 - 35 ℃
Ideal Temperature
Water: Prostrate knotweed thrives in humid environments and prefers consistent moisture, requiring weekly watering. It is moderately drought-tolerant and often grown outdoors, where its growth cycle benefits from natural rainwater, enhancing seasonal vigor.
Propagation: Prostrate knotweed propagates well by sowing in spring, with seedling emergence signaling success. The difficulty level is moderate, requiring consistent soil moisture for effective propagation.
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