Tom's Blog

Saturday, April 26, 2008

The problem with red raspberries in savanna restoration

Red raspberries are a real menace in savanna restorations. Once the habitat is opened up, they flourish in the increased sunlight. I did a literature review and discovered that red raspberry seeds will survive many years in the soil. The longest with hard data was 100 years, which, as far as we are concerned, is infinite.

Although blackberries and black raspberries can be mostly eradicated by cutting and herbicide treatment of the cut stems, this does not work with red raspberries. They are fiercely clonal, and make dense stands. Cutting and treating is useless.

Last year I developed a new procedure. After all the stems were top-killed by a burn, they resprout at the base. At each stem there is a rosette of new growth. As soon as these rosettes are large enough, they were sprayed with Garlon 3A (foliar concentration). The rosettes were rapidly killed. However, not all the stems resprout at the same time, so it is necessary to return and spray the new rosettes two weeks later. And finally, a third spraying to get all the stragglers.

In marked patches, I found that this procedure eradicated the clone without too much negative effect on the "good" species.

Time consuming and expensive, but hopefully worth it.


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