The broad leaf weed Russian thistle is a large and bushy noxious annual plant. This tumbleweed can be extremely difficult to contain, as with the death of the mature plant, it dries up and the species seeds become dispersed by wind. Russian thistle can greatly reduce crop yield and quality, as it depletes soil moisture, and can be a mode of transport for disease and insect pests.
The first leaves are very long and narrow; the height of the immature plant can range from 10-30 mm. The leaves typically grow alternate but are hard to distinguish between other species having opposite leaf formation.
The mature plant grows like a bush with mature leaves having a greenish blue colour and a sharply pointed shape. The leaves can be either smooth or hairy. The mature plant can range anywhere between 30-90 cm in height. The flowers bloom in July, where they have no petals, and the sepals are a pinkish colour and grow in whorls.
Optimal growth conditions
The optimal conditions for the growth of Russian thistle are high nitrogen levels within the soil with dry soil conditions.