|Scientific Name||Galeopsis tetrahit L.|
|Common Names||English: Common Hempnettle; German: Gemeiner Hohlzahn; French: Galéopsis tétrahit; Spanish: Galeópside, Tetrahit|
|Description||Annual, seed-propagated weed with taproot; up to 40 cm (15.74 inch) tall.|
Swollen stem nodes, stems square in cross-section. Pink-to-bluish-purple flowers arising from the axils.
Strong, smooth-edged, oval-stemmed, with two lobes at the base and a rounded tip.
Square in cross-section, with swollen stem nodes; simple or branched, rough owing to their stiff hairs.
Long oval in shape, with downy hairs on both sides, with large regular teeth and reddish-brown stem.
Dense whorls of flowers in the axils, pink-to-bluish-purple.
Upper lip helmet-like, middle lobe of the lower lip almost square, with a yellow blotch, edged with purple, on the lower lip.
Nutlets enclosed in the calyx.
Oval, grayish-brown, with irregular, pale, warty blotches. Seeds germinate at a depth of 1-4 cm (0.39 - 1.57 inch) in early spring.
Viability of Seeds
Up to 5 years.
Approx. 200-2,000 per plant.
Arable land, sometimes in woods, fens and wet heaths, waste ground, disturbed sites, railroads.
Fresh loams and sandy soils with a high nutrient (nitrogen) content.
Additional Crop Information
Spring cereals, row crops, gardens, fruit tree cultivation, vineyards.
G. tetrahit is the most important member of the hempnettle family. It moderately reduces yield and interferes with combine harvesting.
Useful non-chemical contribution to Integrated Weed Management
The soil surface should be cultivated in spring and autumn. Regular hoeing in spring will destroy most seedlings. Delayed crop drilling allows time for pre-sowing cultivations to control the first flush of seedlings.
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