How to Remove French Broom: Do the Math!

Michael J. Vandeman, Ph.D.

February 22, 2020


†††† It seems to me that the vast majority of the ďexpertsĒ are missing some important points:


1. Invasive species are so widespread, and so successful, that no land manager has the manpower or funds to remove them. The only solution is to use volunteers.

2. Volunteers are voluntary! They are not employees! You canít tell them what to do. You can only make suggestions. If they donít enjoy what they are doing, they wonít volunteer!

3. Volunteersí time is precious. Donít waste it! An employee is paid by the hour, so they donít care how long the job takes or whether the methods used are the most energy-efficient. Volunteersí time, on the other hand, is their own. That makes it critical to determine the most energy-efficient methods, i.e., the methods that accomplish the most important task (eradicating the weeds) in the minimum time with the minimum expenditure of energy.

4. Measuring energy expenditure is difficult. You must estimate.

5. Science, not politics, should rule.

6. The weed wrench: The weed wrench is heavy! It doesnít always work. Some plants are too large to remove with the weed wrench. Sometimes the ground is too soft to provide the necessary leverage. Sometimes the stems are too small for the weed wrench to grasp. Thus you need another tool, such as a pruning saw. While using one tool, you have to put the other one down. Then when you need it again, you have to search for it in an unfamiliar, chaotic landscape. I have spent an embarrassing amount of time searching for a tool or bag. I am still searching for a book that fell out of my bag a month ago. Why not just use the pruning saw, and forget about the weed wrench?

7. Peeling the bark: Iím told that peeling the bark from a cut stem will prevent it from re-sprouting. Iím sure that itís true. But who has the time to do that? My priority, remember, is eradicating the infestation with the minimal expenditure of time and energy. It takes just a few seconds to cut a French broom stem. Peeling the bark would take several times as long. Recently I spent ten 8-hour days cutting about an acre of French broom, which was about twice as long as I expected it to take. Imagine how long it would have taken if I had to peel the bark from all of those thousands of stems! Life is too short for that. And how do you choose which stems are big enough to make it worthwhile to peel them Ė another decision to make that would add further delay? Of course, if you donít peel the bark, you will have to return later to cut any re-sprouts. But you have to return anyway, since there are seeds in the ground! Each time the plant re-sprouts, the sprouts will get smaller and much easier to cut. I find that I can grab a large bunch of them with one hand and cut them all in one or two seconds with the other hand. Since the plant can only store a finite amount of energy in its roots, if you keep cutting it, you will prevent the plant from adding to that store, and it will eventually be exhausted, and the plant will die. That is a simple consequence of the law of conservation of energy: energy canít be created or destroyed; it can only be transferred from one place to another.

8. Removing the cuttings: This is a huge waste of your volunteersí time! The most important task is eradicating the plant. As long as it isnít fully eradicated, it will eventually recover completely, and all your efforts will be for naught. Everything else is secondary. Some sites are so far from a road that carrying out all the cuttings would take an enormous amount of energy and time. Try dragging a huge French broom plant through a trail-less field of coyote brush, blackberry bushes, poison oak, bay and oak trees, etc.! You are lucky to just walk through such a field unscathed, much less carry cuttings and then try to find your tools again! It is also ecologically stupid to remove cuttings because of the nutrients they contain, which should be left on site. Removing plants will eventually impoverish the soil Ė not something that we should be doing to our precious parks! I asked the director of the University of California Botanic Garden about this issue, end he agreed with me.

9. Rain: Rain is your friend! After a rain, plants Ė even fairly large French broom plants .5 to .75 inches in diameter Ė can often be pulled out of the ground by hand.

10. Cutting French broom: If it is small enough (e.g. under .5 inch thick), try to pull it out of the ground by hand. If it budges, with patience you will be able to pull it out by hand. If not, donít wreck your back by trying to force it; you are not Superman! If itís too large to budge, start by bending it to one side (e.g. to the left, if you are right-handed), and try to crack it before it is fully cut. Otherwise, you may find the saw stuck in its groove. (Of course, you should be wearing leather gloves to protect your hands. I wear nitrile gloves under my leather gloves, because they will stretch to cover my wrists and protect them from ticks and poison oak.) Of course, try to leave the cuttings where they wonít interfere with the native plants.

11. How to pull French broom out by hand (this is always preferable, if possible, since it will be very unlikely to regrow): (a) plant your feet on both sides of the stem, next to it; (b) grab the stem near the base, with both hands (Iíve noticed something paradoxical: if I canít pull up a plant with one hand, I can often do it with both hands, even if the second hand does no work!); (c) pull uphill; (d) if the stem slips out of your hand(s), wrap it around your hand, or grab it with one hand and use the saw with the other hand to pull on the base of the stem; (e) if it is small enough to pull out with one hand, use your less favored hand, to save your favored hand for the hardest work (e.g. if you are right-handed, use your left hand to pull out the smallest plants); (f) if two stems are separate plants, pull them out separately; if they belong to the same plant, pull them together; (g) French broom stems have a tendency to bend just above the root; sometimes you can make use of this bend to twist the plant around and around until the root breaks; then you can pull it out of the ground by hand; (h) after a while, you will learn the amount of tension required to uproot French broom; if you suddenly find a stem that is much harder (e.g. a tree or cotoneaster) or easier (e.g. coyote brush) to uproot, you may have inadvertently grabbed the wrong plant; French broom often grows intermingled with other plants Ė be careful to grab the correct stem.

12. Poison oak: learn how to recognize poison oak in the winter, when it has no leaves. The stems are smooth, and still carry enough oil to make you miserable!

13. Be sure to carry plenty of water. I donít carry any other food. I find that the work is so engrossing that I never think about eating, and I find that I lose all the weight that I had been unable to lose through normal means Ė another bonus of work that is already very relaxing, good exercise, and a great opportunity to view wild animals. And how many other activities do you know that produce instant results?!





California Invasive Plant Council:

California Native Plant Society

Weed Photo Gallery

See also