Bracken is a herbaceous perennial plant, deciduous in winter. The fronds are produced singly from an underground rhizome, and grow to 1-3 m tall; the main stem is up to 1 cm diameter at the base. The rhizomes typically grow to a depth of 50 cm, although in some soils this may extend to more than a metre.

The plant is carcinogenic to animals when ingested, although they will usually avoid it unless nothing else is available. With cattle, bracken poisoning can occur in both an acute and chronic form, acute poisoning being the most common. In pigs and horses bracken poisoning induces vitamin B deficiency.

Methods of control