In its native country, the U.S., rough-fruit amaranth is considered a "superweed": a single plant grows over two meters high and can produce up to one million seeds. The species is not yet found in Austria, but the plants have already been identified in northern Italy, Croatia and Slovakia.

Rough-fruti amaranth likes it warm, low summer temperatures inhibit its spread. Currently, only the south of Austria offers conditions for the plant, but climate model predictions for the next decades indicate a sharp increase in climatically favorable regions in Austria.

The heat-loving species would benefit from the temperature increase and from a prolonged vegetation period.