Bracken (Pteridium aquilinum) is a native British fern commonly found in woodland and heath land. It is tolerant of a wide range of soils and climates and has an extensive underground network of two rhizome types which makes control difficult.
Is it harmful?
Fronds are poisonous to cattle and horses and harbour disease-carrying ticks and carry carcinogenic spores, however sheep and cattle normally avoid it.
The fronds are most toxic at the newly emerged or crozier stage. The fronds become less toxic with age but it is important that bracken cut for animal bedding should have died back entirely. The rhizomes are also poisonous and are a potential hazard to pigs that may uproot them and to cattle when ploughing exposes the rhizomes. Bracken is considered a human health hazard due to the carcinogenic spores. It also provides a habitat favoured by sheep ticks which transmit Lymes disease.
How to kill Bracken
Treating bracken with Asulox
The specialist choice for bracken control. For agricultural, forestry and amenity use, the selective weed killer Asulox is best used when the bracken is at waist height or just below. Treat with via a knapsack sprayer when the fronds (leaves) are at full extension and use the wetter Warrior. This reduces the surface tension of any water on the leaf allowing the Asulox to work effectively.
Follow up treatments:
Owing to the nature of bracken growth and the difficulty of spraying sheltered or uneven terrain, 100% control is rarely achieved. Any bracken surviving should be sprayed as soon as it recovers to full green frond. This may be the year following the initial application but more likely the second year following initial application. If a programme of follow-up sprays is undertaken the bracken-free period will be greatly extended.
If no follow-up treatment or land improvement programme is carried out, re-spraying may be necessary within 5 years
Treating bracken with Roundup
Asulox is a selective weedkiller meaning it will control the bracken without killing surrounding grass. If you are not worried about keeping the grass then an alternative product is Roundup ProVantage 480 (an alternative to Roundup ProBiactive 450). Timings for control of Bracken are similar to Asulox – with spraying recommended as fronds approach full size in July/August. Roundup ProVantage has the added benefit of being able to be applied either via a knapsack sprayer at 3.75 L/ha or via a tractor mounted weed wipe or hand held weed wiper. Treated fronds will die back within four weeks of treatment; future re-treatment may be needed.
Bracken can also be controlled using Roundup ProActive 360 (formerly known as Roundup ProBio).
PG TopTip – Using a blue marker dye can help you to see where you have been when controlling large areas of bracken
Treating bracken with Tordon 22K
Tordon 22k was a selective, residual herbicide containing picloram designed to control a wide range of perennial and annual broad-leaved weeds as well as bracken and brambles. Unfortunately Tordon 22k was removed from sale in 30th June 2014 and can only be used until 30th June 2015.
It is now recommended to use Asulox (formerly known as Asulam) to control Bracken.