Physical control, how useful is it?
The VBT continues to disseminate information on best practice blackberry control via the Weeds of National Significance Blackberry Control Manual. Physical control is an integral part of this by reducing chemical usage and improving access and can be part of an integrated or stand-alone measure. An integrated program may include the use of physical measures before applying chemical, but the VBT has found that some land managers are not allowing sufficient re-growth before application.
The Blackberry Manual states that following any physical control measures, including slashing, there must be at least 50cm of re-growth before applying chemical. This allows enough products to translocate into the blackberry plant’s extensive root system. As many landholders, including organic farmers, are choosing non-chemical options, the VBT is keen to encourage best practice to achieve good results.
Frequency and timing in applying physical control techniques as a stand-alone technique is the key. For instance, the VBT has received correspondence from people slashing once and then forgetting about it. To their surprise the blackberry bush grows back bigger, denser and stronger. The blackberry manual clearly outlines the need to use physical control measures every two to four weeks while the blackberry is actively growing. This ensures the blackberry is depleted of its energy resources.