Fathen is an extremely fast-growing weed with excellent survival mechanisms. In good conditions it can grow up to 1m high before flowering, but in dry situations it will flower and produce seed before it is 4cm high. It also has a very thick waxy layer which coats the leaves in dry weather. This is designed to hold moisture in the plant, but it is equally effective at preventing absorption of herbicides. Fathen can grow densely in spring-sown pastures. Pre-flowering spring gives the most effective control.