Booderee continues to make great strides in its fight against the invasive African weed bitou bush.
Bitou bush was planted in the 1960s to help stabilise the shifting dune behind Bherwerre Beach. It quickly spread
from there to the dry sclerophyll forest next to the dune system, spreading to the point where this area had one
of the worst infestations on the New South Wales south coast.
Bitou bush is a perennial evergreen shrub in the daisy family, a native of South Africa and a major environmental weed of dune and coastal forest in southern Australia. It is classed as a Weed of National Significance.
In the 1990s, with Booderee now a national park, two techniques were developed to revolutionise bitou control.
The first of these was aerial spraying. This technique involves a helicopter spraying a high concentration of
Glyphosate, a commonly used non-selective herbicide, over remote or large-scale bitou infestations.
Despite Glyphosate being non-selective, it can be applied without harming native vegetation if sprayed during
winter when bitou bush is still biologically active but most native plants are dormant.
The other major technique was the spray-burn-spray method. This involves first spraying bitou, then burning it once it has died and dried. As with many Australian plants, burning stimulates mass germination in bitou. After a couple of seasons the plants from this mass germination are also sprayed, largely clearing the infestation.
Over the last six years, these techniques have seen the park make great progress in controlling bitou bush,
cutting infestations back dramatically. In 2004 the distribution of bitou was aerially surveyed (Figure1). As a result, the park decided to attack the main infestations behind Bherwerre Beach using the aerial spray-burn-spray method.
Since then the park has surveyed the area in 2010 and again targeted the main bitou infestation with spray-burn-spray.
Why do we want to get rid of Bitou bush?
It competes with native plants for sun, water and nutrients and forms an impenetrable growth under which little else can grow.
How do we control Bitou bush?
The bush is sprayed either by hand or helicopter with Glyphosate (Roundup), a non-residual herbicide.
Cured Bitou is burnt to stimulate germination, then before flowering the seedlings are aerially sprayed.
How do we know whether it has been successful?
The extent of the heaviest infestation (greater than 50 per cent bitou coverage) has declined by 70 per cent between 2004 and 2007 due to spraying and burning.
Bitou bush | Photo: eyeweed