PlantFiles: Western Bracken Fern, Brake, Bracken, Northern Bracken Fern, Brackenfern
Pteridium aquilinum

Very invasive. I've been pulling it from years. The slightest piece left tucked up against a rose bush regenerates and continues to spread. After winning a massive fight against Kudzu, it will eventually consume the entire globe.

The broadly triangular thick fronds have a coarse texture and are dark green. The edges of the segments are curled under. The frond can reach the dimensions of 3 ft. long by 3 ft. wide and the whole plant grows to about 4 ft. high. It grows in pine forests, burned areas, open woodlands and meadows at an elevation range of about 5000-8500 ft. This fern is the most common of ferns in Arizona, it's habit is weedy and tends to grow in large colonies. It dies with the first frost. Amongst other places in Arizona, it can be found at Black Canyon Lake.

This plant is invasive. It has spread 20 feet into my lawn from the neighbors yard in one year even tho' I have cut or stomped each frond weekly, and mowed. Don't consider planting it. It does not seem to be controlled by Round-Up.

This fern is native to the USA (every state except Nebraska), Belize, Costa Rica, El Salvador, Guatemala, Mexico, Nicaragua, Panama, Argentina, Bolivia, Colombia, Ecuador, Paraguay, Peru, Venezuela, Gabon, Madagascar, Sierra Leone, South Africa, Tanzania, Uganda, Zambia, the Philippines, and Vietnam.

Considered an endangered species in the U.S. state of Ohio.

Pteridium aquilinum thrives here in zone 9b, but is difficult to find in nurseries locally. It is invasive, and once established spreads quickly. This can be controlled by withholding water from adjoining areas.

The bracken is also poisonous to molting insects. It contains many different kinds of ecdysones, naturally occuring hormones that stimulate molting in insects, the hormones that Neem oil, often used to control lily beetles, mimic. These are also among the more popular ferns whose fiddleheads are harvested and eaten. While the fiddlehead stage is generally considered safe to eat, a high incidence of stomach cancer among bracken-eating populations in Britain and Japan has been noted and is being investigated. Bracken is also able to produce hydrogen cyanide in response to insect attacks. When its tissue is damaged, it releases an enzyme that splits prunasin, yielding hydrogen cyanide. As noted in the prior note, bracken can be poisonous to livestock, as it contains thaminase, an enzyme that erodes thiamin and will eventually result in B1 deficiency in cattle with a diet high in brackens. This is the genesis of the "bracken staggers", the loss of balance and coordination often noted in animals with B1 deficiency.

Bracken is found in many places throughout the world. While it's the only species in the genus there are around 5 different sub species found in different regions.

Has large, triangular fronds that grow straight from the rhizome on a leaf stalk. It can grow to 10ft tall but it's more likely to be within the range of 2-6ft. They reproduce by spores and rhizomes that can spread over 10 feet from the parent plant.

It's extremely invasive and is not one to be grown in a small garden. Fire won't kill it, only the fronds, in fact they like fire as it helps them recolonise an area quickly! The dried fronds are also a fire risk. It's resistant to various pesticides and one of the few effective controls used here in the New Forest is cutting the entire ferns to the ground early in summer, this depletes the nutrients available to the rhizomes and helps keep on top of the spread.

It's poisonous to most domestic livestock, single stomached animals such as horses and pigs are affected very quickly. Sheep and cattle are more likely to suffer from an accumilation of the toxins in their bodies over time. However, young sheep and cattle who have never met Bracken before can suffer and die from ingesting this plant in large amounts in a short time. Deer seem to be able to cope reasonably well.

So is there anything good about Bracken? It was once used as thatching material and fuel (the dry fronds burn readily) and was used as rent payments. The ash from a bracken fire was used as a source of potash by some industries. It was also used and still is to a small extent as an animal bedding. Certainly in the New Forest it was collected as a bedding and has got out of control since that practise has stopped.

More uses are currently being investigated.

Bracken also provides valuable summer cover for various wildlife and insects.