Gorse (Ulex europeaus)

Control gorse in two stages. First, control established plants. Second, control new plants emerging from seeds that may last more than 30 years in soil. The most effective control program usually combines herbicides, burning, and cultivation or mowing. Establishing competitive pasture species, forest trees, or other crops helps resist gorse invasion as well as other weeds. A publication on the biology and control of gorse (Gorse, PNW 379, revised July 2001) is available from the Extension Service. When using herbicides, it is crucial to thoroughly wet foliage. Best timing is after bloom drop, but applications at other times usually give good control also.

2,4-D LV ester (several products)

Rate 0.75 to 1.5 lb ae/A or 0.5 to 1% concentration for handgun sprayer application.

Time Apply to actively growing plants after bloom drop in the spring.

Caution Do not let spray drift onto agricultural crops. Do not graze dairy animals within 7 days after application.

Site of action Group 4: synthetic auxin

Chemical family Phenoxy acetic acid

dicamba (Banvel, Rifle, or Clarity)

Rate 0.75 to 1.5 lb ae/A or 0.5% to 1% concentration for handgun sprayer application.

Time Apply to actively growing plants after bloom drop in the spring.

Caution No waiting period between treatment and grazing for nonlactating animals (see label for restrictions on dairy animals). Remove meat animals from treated areas 30 days before slaughter. Rates above 2 lb ai/A may temporarily injure many grass species. Newly seeded grass (see label) may be injured at rates above 0.75 lb ai/A. Do not exceed 8 lb ai/A per season. Kills legumes.

Site of action Group 4: synthetic auxin

Chemical family Benzoic acid

glyphosate

Rate 1.5 to 3 lb ae/A or 1.5 to 2% solution for handgun sprayer application.

Time Apply to actively growing plants after bloom drop in the spring.

Remarks Adding a recommended surfactant improves results.

Caution Glyphosate kills grasses and most other desirable species needed to compete with new gorse plants.

Site of action Group 9: inhibits EPSP synthase

Chemical family None generally accepted

metsulfuron (Escort and others)

Rate Escort: use 0.6 oz ai/A (1 oz/A)

Time Apply to actively growing plants after bloom drop in spring.

Remarks Include a silicon-based surfactant. Application sites differ among products; consult labels.

Caution Do not let spray drift onto agricultural crops. Apply only to pasture, rangeland, and non-crop sites.

Site of action Group 2: acetolactate synthase (ALS) inhibitor

Chemical family Sulfonylurea

picloram (Tordon)

Rate 0.5% concentration for application with a handgun sprayer.

Time Apply to actively growing plants after bloom drop in the spring.

Remarks Adding a suitable surfactant at 0.25 to 0.5% will improve results.

Caution Most formulations are restricted-use herbicides. Refer to label for grazing restrictions. Avoid drift to sensitive crops.

Site of action Group 4: synthetic auxin

Chemical family Pyridine

triclopyr ester (Garlon 4 or Remedy) or triclopyr amine (Garlon 3A) or triclopyr + 2,4-D ester (Crossbow)

Rate 0.5% to 2% concentration for application with a handgun sprayer.

Time Apply to actively growing plants after bloom drop in the spring. Garlon 4 and Crossbow can be used for basal bark applications any time of year.

Remarks Adding 0.25% to 0.5% of a suitable surfactant to Garlon 3A improves results. No surfactant is needed with Garlon 4 or Remedy. Use the higher rates on larger plants and on solid stands of old plants.

Caution Garlon products are registered for use on rights-of-way, industrial sites, and forestry (release and site preparation). Crossbow and Remedy can be used on permanent pastures and rangeland up to 1.5 lb ae/A. Observe all grazing and harvesting restrictions.

Site of action Group 4: synthetic auxin

Chemical family (triclopyr) pryidine; (2,4-D) phenoxy acetic acid