|Scientific Name||Atriplex patula|
|Common Names||English: Common orache; German: Spreizende Melde; French: Arroche étalée|
|Description||Annual weed, propagating itself by seed, occurring in many forms, vigorous, 30-90 cm (11.81 - 35.43 inch) tall and branching with a taproot.|
Either male or female flowers on each plant; lower stem practically square in cross-section.
The lowest teeth on the leaves are more pronounced than in Chenopodium album and point towards the leaf tip.
Long, narrow, often with a rounded tip.
Often deeply grooved and branching with very long, horizontal side branches.
Alternate, petiolate, ovate to lanceolate, lower leaves often hastate, lightly dentate, upper leaves entire, dark green, young leaves usually farinaceous.
The upper surface of each blade is hairless or glabrous, while the lower surface is often white-mealy.
Diecious (Chenopodia spp: monoecious).
Flower clusters in erect, spike-like racemes; whitish-green.
Midsummer - autumn.
A. patula produces two types of the fruit. The large one is 2-3 mm (0.078 - 0.12 inch) long with a single ochre-colored seed; the small one is 1-2 mm (0.039 - 0.078 inch) long with a single black seed.
Germination from late spring-autumn.
Each seed is covered by a thin rough membrane that is difficult to remove.
Viability of Seeds
100-6,000 per plant.
Woodland borders, gardens, edges of yards, unmowed areas, areas along railroads and roadsides, dumps, and waste areas.
Humus-rich, nitrogen-rich and well-aerated soils.
A. patula is a typical example of a late-season weed in crops which mature late. It competes strongly for water and nutrients. It considerably reduces yield and seriously interferes with harvesting.
Useful non-chemical contribution to Integrated Weed Management
The high seed production and long viability of seeds in the soil requires intense soil cultivation to reduce seed bank and induce fatal germination.
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