Broom - Howard - St Arnaud

(Cytisus scoparius)

Containment Pests

Broom is a fast-growing, perennial shrub growing to 3.5 metres high. It has sparse, green, trifoliate leaves; yellow pea-like flowers and conspicuous seed-pods. The black seeds are dispersed by a ballistic mechanism and remain viable for many years. They are dispersed along waterways and redistributed in river gravels, and in dirt on machinery and vehicles.

Reasons for the Strategy

Broom is regarded as a serious production and environmental pest in the Tasman-Nelson region. It is an Broom shrub with bright yellow flowersaggressive competitor for light, nutrients and moisture; dense stands of Broom can shade out most species. It is very competitive in lightly grazed pastoral situations, forming thickets that obstruct grazing. Broom can invade plantation forests, often from gravel brought in for roading, and re-establish after forests have been harvested from seed that has been lying dormant. It is capable of smothering native species in regenerating shrublands and remaining as the dominant species for many years. In many people’s perception, Broom degrades amenity values.

Broom is assessed at “4” on the infestation curve for the Howard-St Arnaud area and “7” for the rest of the Tasman- Nelson region. Broom is widespread throughout most of the Tasman-Nelson region, except in the Howard-St Arnaud area. The low incidence of Broom in the Howard-St Arnaud area, extensive areas of suitable habitat, and the potential for it to cause significant adverse effects, mean the benefits of containment far outweigh the costs. Elsewhere, the distribution of Broom has reached a level where the most cost-effective form of control is to require boundary control, and to invest in biocontrol. This will assist in protecting land clear, or being cleared of Broom, from invasion by Broom growing on adjacent land.

Objective

To address the adverse effects of Broom in the Howard-St Arnaud area by preventing any increase in its distribution and density during the term of the Strategy.

Alternative Measures

The alternative option of “do nothing” or relying on voluntary control will not achieve the objective of reducing the distribution and density of Broom in the Howard-St Arnaud area, and will result in significant additional costs to the community with respect to lost production, and the increased cost of control in the future. Requiring progressive control in the Howard-St Arnaud area would not be costeffective, given its distribution and persistence.

Strategy Rules for Broom

The occupier in the Howard-St Arnaud area shall destroy all adult and juvenile forms of Broom on land that they occupy. A breach of Strategy Rule 6.x.5 is an offence under Section 154(r) of the Biosecurity Act 1993.

Biosecurity Act Requirement

No person shall knowingly sell, propagate, breed, release, or commercially display Broom, under Sections 52 and 53 of the Act.