Overview
The plant Helianthus annuus when in competition with crops greatly reduces crop yields due to its aggressive growth habits, such as the formation of a high canopy which blocks out sunlight, as well as its high nutrient requirement.
Main description
Seedling
The cotyledon of volunteer sunflower is oblong in shape and ranges from 15-40 mm in height. Its first leaves sprout opposite, are dull green and covered in short hairs, which are rough to the touch.
Mature plant
The leaves are 7-30 cm long and are heart shaped, with a central stem that is large and thick. The key distinguishing feature is its large yellow bloom head that grows upwards of 400 cm. The individual inflorescence is made up of 1000-2000 individual-true flowers, combined at a common receptacle. It has no stamens or pistils and propagation occurs only through seed.
Optimal growth conditions
The common habitats of volunteer sunflower are woodland meadows, cultivated and abandoned fields and pastures, areas along railroads and roads, urban waste areas, dry open plains and foothills, as well as in fields cultivated to sunflowers the previous year. The optimal temperature range for growth of Helianthus annuus is 16-30oC with a low tolerance to salinity. This species has the ability to grow in a wide range of soil types ranging from sands to clays.
Crops
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Barley
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Canary Seed
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Established Grasses
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Fall Rye
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Field Corn
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Flax
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LibertyLink Corn Hybrids
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Oats
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Seedling Grasses
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Sweet Corn
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Wheat
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