|Scientific Name||Polygonum persicaria (L.)Small|
|Synonyms||Periscaria maculosa Gray|
|Common Names||English: Spotted ladysthumb, redshank; German: Floh-Knöterich; French: Renouée persicaire; Spanish: Persicaria, Duraznillo|
|Description||Annual, seed-propagated weed with ramified taproot.|
Ocrea with small hairs emerging from the upper end.
Characteristic purple splotch in the center of the leaf. The spot is not always present but typical.
The perianth is somewhat variable in color.
Long-oval, rounded tip, dark green to reddish.
Similar to Pale persicaria (Persicaria lapathifolium), up to 80 cm (31.49 inch) high.
Lanceolate, widest in the middle, upper surface often with dark spots, short-petiolate or sessile.
Membranous tubes at the leaves' base often with short, appressed hairs.
Visibly ciliate at the margin.
Small, pink or whitish; in erect, dense, terminal or axillary, spiciform inflorescences.
Perianth parts glabrous, ovate to orbicular.
Midsummer - autumn.
Achenes typically 2-sided, black, shiny, to +/-2mm (0.078 inch) long.
Germination from spring - summer.
Seed germination depth usually 1-3 cm (0.39 - 1.18 inch).
Seeds are lentiform and shiny black.
Viability of Seeds
Moist to wet waste ground, disturbed sites, meadows, streambanks, roadsides, railroads.
Fertile, nitrogen-rich, friable, well-aerated soils.
P. persicaria is a serious agricultural weed in many temperate regions. It greatly reduces yield and interferes with combine harvesting. Seed production is stimulated by wet conditions.
Useful non-chemical contribution to Integrated Weed Management
A combination of preventive, physical and chemical control methods may reduce P. persicaria development.
It is important to rotate modes of actions in order to avoid resistant weed populations.
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