Kenwood Press

Serving the communities of Kenwood, Glen Ellen and Oakmont

email print

Pull out invasive French broom now

Time to pull this unwelcome invader. Photo by Jay Gamel.

Every spring, you can drive or walk around and see a pretty, tall, leafy shrub with bright yellow flowers. But itís really not pretty at all. French broom is highly aggressive and out-competes native plants, displacing them, and can dominate native flora with its thick stands that can get up to 10 feet high.

A member of the pea family, French broom can alter the soil makeup by increasing the level of nitrogen in the ground, which encourages other non-native weeds to grow. It isnít very tasty either (the flowers and seeds can be toxic), so the wildlife wonít eat it, and their normal diet can be affected because the pervasive shrub is taking the place of other edible plants.

And, the oils in French broom make it easily combustible, thus increasing fire hazards.

French broom has its most rapid vegetative growth from April to July, and becomes reproductive at two to three years of age, if not sooner.

French broom spreads so easily because the seed pods open explosively and throw an amazing number of seeds as far as three to four meters.

According to the California Invasive Plant Council, a medium sized shrub can produce over 8,000 seeds a year, and seeds can survive at least five years in the soil and often much longer, thanks in part to a hard coating that covers the seed.

Itís hard to get rid of French broom entirely because it reseeds so easily, but the most effective eradication method is to use your hands. It is not good to cut it because it comes back stronger and the roots get harder to pull.

This is a great time to pull out French broom, when the earth is soft and the roots will let go easily. Itís easy to see once itís blooming and it is really important that it doesnít go to seed.

Removal sites should be looked at once a year in order to get rid of new seedlings, and this needs to be done for five to 10 years.

For more information on French broom go to the California Invasive Plant Councilís website at

Weather Underground PWS KCAKENWO2