RE: Marin Co. weed management area contacts; calif. weed laws (was scotch broom!)

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California's weed laws are posted at the Calif. Dept. of Food & Ag site:

http://pi.cdfa.ca.gov/weedinfo/weedlaws.html

Info on Marin/Sonoma Weed Management Area (county weed management program) is at:

http://www.cdfa.ca.gov/phpps/ipc/weedmgtareas/Marin/Marin_hp.htm

Marin/Sonoma Weed Management Area

Contact: Amanda Stephens (415) 499-6700
Bruce McArthur (707)565-2371

The following Integrated Pest Mgmt control and management methods for scotch broom are from the CDFA Encycloweedia:

http://www.cdfa.ca.gov/phpps/ipc/encycloweedia/encycloweedia_hp.htm

CONTROL METHODS:

Mechanical: The weed wrench is one of the most effective techniques for the complete removal of French broom Scotch broom, and other brooms. The wrench locks on to the base of the stem and leverage is used to remove the entire plant. The wrench was specifically designed for complete broom removal to prevent any resprouting. The weed wrench is effective on many trees and shrubs up to a 2.5 inches in diameter. Some soil disturbance will occur with removal, which may favor new seedlings or deeply bury seeds in the soil. However, the disturbance is minimal and the technique can be employed even on steep slopes. Generally, a flush of broom seedlings may occur directly beneath the previously canopied area, which will need to be controlled. Mowing or cutting the shrubs may prevent seed production. However, resprouts will need to be managed.

Biological: There are currently no registered biological agents for use on French broom or gorse. However, the gorse weevil (Apion ulicis) was accidentally introduced into California in 1953 from France. The weevil feeds on seeds, spines, and leaves of the gorse plant, but has had limited success for control. There are two approved insects for Scotch broom, a stem miner (Leucoptera spartifoliella) and a seed beetle (Apion fusciostre). However, both insects have had limited success in California.
Intensive goat grazing has been used to control brooms and gorse. Goats are most effective in controlling regrowth following initial control strategies. Goat grazing may be difficult if you are trying to reestablish natives during the control process since goats will also likely browse the native plants.

Chemical: For brooms and gorse, glyphosate applied as a 2-3% v/v foliar spray has been an effective treatment. Triclopyr applied as a 25% basal bark application in an oil carrier is also effective. Some resprouting may occur with these treatments and follow-up management will be necessary for future flushes of seedlings.

Prescribed fire: Brooms and gorse are highly flammable. Fire has been used to eliminate large impenetrable thickets and prepare areas for easier follow up treatments. Fire stimulates seed germination and large flushes of seedlings may be expected following burning. Fire appears more effective in controlling resprouts when there is adequate grasses to carry the fire.

MANAGEMENT FAVORING/DISCOURAGING SURVIVAL: Established infestations are difficult to eliminate because large, long-lived seedbanks typically accumulate. Minimizing soil disturbances, monitoring, and manually pulling young plants when discovered can help prevent new infestations. Machines and tools used to remove stands may inadvertently transport seed to uninfested sites. Cutting Scotch broom shrubs to ground level at the end of the dry season can help reduce re-sprouting from the crown. Planting native shrubs and trees within and around broom stands can eventually help to minimize infestations by shading. Goats confined to a small area can help control stands of young shrubs or young re-growth from cut shrubs. Prescribed burns can eliminate above ground growth, but do not prevent re-sprouting from the crown and may stimulate a flush of seed germination.

 I think your local weed management area staff will be most anxious to help you with your broom problem.  jkn