Polygonum persicaria

Names

Spotted ladysthumb seedszoom...
Spotted ladysthumb seeds
Young spotted ladysthumb plantzoom...
Young spotted ladysthumb plant
Spotted ladysthumbzoom...
Spotted ladysthumb
Flowering spotted ladysthumbzoom...
Flowering spotted ladysthumb

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

Descriptions

Description

Annual, seed-propagated weed with ramified taproot.

Characteristic Features

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.

Cotyledons

Long-oval, rounded tip, dark green to reddish.

Stems

Similar to Pale persicaria (Persicaria lapathifolium), up to 80 cm (31.49 inch) high.

Leaves

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.

Propagatio Organs

Flowers

Small, pink or whitish; in erect, dense, terminal or axillary, spiciform inflorescences.
Perianth parts glabrous, ovate to orbicular.

Flowering Period

Midsummer - autumn.

Fruit

Achenes typically 2-sided, black, shiny, to +/-2mm (0.078 inch) long.

Seeds

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

30 years.

Propagation

By seeds.
200-800 seeds/plant.

Occurrence

Habitat

Moist to wet waste ground, disturbed sites, meadows, streambanks, roadsides, railroads.

Soil

Fertile, nitrogen-rich, friable, well-aerated soils.

Crops

Agricultural Importance

P. persicaria is a serious agricultural weed in many temperate regions. It greatly reduces yield and interferes with combine harvesting. Redshank produces many seeds in wet seasons.

Control

Integrated Crop Management

A combination of preventive, physical and chemical control methods may reduce P. persicaria.

Chemical Control

It is important to use herbicides with different modes of actions in order to avoid resistant weed populations.

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