Overview of French Broom Problem

French Broom

The plant is a problem for a number of reasons. If you need simple, pragmatic reasons, the number one is that it is a fire hazard. It grows and reproduces rapidly, creating a dense thicket as it establishes. Then, as plants approach 10 years of age, many of them die, leaving huge quantities of thin, flamable sticks waiting for a spark. Also, French Broom has a relatively puny root system. Compare the effort to pull a blue blossom with the effort to pull a Broom - the Broom pulls right out of the ground when the soil's wet. This root system contrasts greatly with the large top of the plant. As the plant gets older it tips over, destabilizing slopes. What appears to be a hillside of vegetation holding the soil in place, if its Broom, turns out to be a landslide waiting to happen.
If you aren't concerned about fire, erosion, or landslides, please be advised that your broom patch is destroying the homes of literally millions of organisms. Few organisms have evolved to feed on French Broom. Currently, two moths and a couple of bees feed on the plant. Deer and rabbits occassionally take a bite. Contrast that with, say, coyote brush or blue blossom (native shrubs) which together support more than 400 organisms. And, those are just two species that lose out in competition when French Broom moves into native habitat. French Broom is threatening coastal prairie, oak woodland, and sandhills habitats - all endangered already by lack of management and fragmentation by developement- which are the exclusive home to 1,000 native plants and many animals locally.
The plant reproduces so quickly that even if you have just one or two plants now (and aren't concerned about the above factors), you could have between 500-2,000 plants in the years to come - JUST from this year's seed production. The seeds explode from ripe pods, spreading for 6 feet around the plant. A mature plant makes 1,000 seeds a year. The seeds last at least 37 years in the soil, so every year you wait to kill the few plants may mean years and years of control to come. Best advice - stop the plants now.
Now, how to best stop the plants. Use what is known as the Bradley method. Start where there are very few plants and work toward the thick patch. Pull the "outliers" - the few that are invading new territory. Pulling is best accomplished by hand when the soil is very wet. If you have a problem pulling, borrow or buy a weed wrench - a tool invented to pop the suckers out of the ground with lever action and steel jaws. When you get to the thick patch, you have a few choices. You could continue to pull, beating the plants back as far as possible each year. Or, you could spray in the same manner- as deep as you can go each year. If you prefer, you could chop the bushes down. If you decide to do this, wait until the end of the summer - when its most dry and hot. Cutting at any other time is counter productive, creating luxuriant regrowth and stonger roots. If you cut at the end of summer, chances are good that you will kill around 80% of the plants. Cutting 2" or greater diameter plants almost always kills them. (Of course, waiting till the end of summer allows one more year of plants to go to seed.)
After killing the mature plants, you will be left with an ocean of seedlings the next winter. These are very easy to pull, but very numerous. Easier than pulling is using a hand held propane torch as soon as possible after the seedlings are recognizable. The beauty of this control method is that you won't kill the grass and won't have bare soil. You can also herbicide the young plants. If you have left over piles of previous year's dead broom- burn it where the seedlings are the thickest- this will go a long way toward killing both the seedlings and the seeds in the soil. (Burning is hazardous! Consult with county fire officials first.)
The frustrating thing about Broom is the repetitive recontrol needed. Breathe deeply and remember that most of the control is in the first five years. Only a few plants a year will sprout thereafter... for 30 years thereafter: just don't let new plants go to seed!

Last Updated on: 2005/03/11 at 06:55:13 PST