French Broom (Genista monspessulana): the problem is the solution?

Hi permies folks,

My in-laws live in Big Sur, and their property is being slowly taken over by French Broom (Genista monspessulana) - though the rate of spread is increasing in recent years since they started trying to suppress it by pulling it.  In general, the plant is greatly maligned in Big Sur and California as a whole for its' invasiveness.  All discussion I've heard is on how to get rid of it - yet the harder everyone works to get rid of it, the more vigorously it comes.

I had a discussion with the about trying to reframe their thinking, that perhaps the "problem is the solution".  The broom is colonizing a hot, south-facing hillside with few trees that is a mix of barren DG, chaparral, and non-native annual grasses.  Being a nitrogen-fixer, being such a vigorous grower, and a producer of a lot of deadfall, it seems clear to me that this plant is filling a niche - it is a pioneer in this area, trying to increase organic matter and soil health while also keeping the soil shaded, in preparation for the next phase of succession - trees, which will eventually shade it out.

My first instinct is to advise them to just let the French Broom be, to allow succession to run its' course, and if they want to speed up succession, to plant some native oaks, madrone, etc. admist it and use it as a nurse plant.  However, a valid concern I am hearing is the flammability presented by the level of deadfall.  Great in a natural fire ecology where fire needs to cycle through periodically, bad if your house is located there.

So - I'm curious on some thoughts regarding this plant, its' role in the ecology, and how it can be best embraced as a solution rather than a problem?  Clearly the suppression technique that the folks in the area mostly employ is an uphill battle that will most likely be lost.

Thanks everyone, in advance, for the thoughts.

French Broom is a serious problem in California and the West Coast because it dominates native plant environments and stops the natives from growing, the main food sources for animals, birds, and it's toxic.  As landowners anywhere it does seem there's a responsiblity to try to co-exist with the environment, taking advantage of how it functions with natives.

That means it's toxic for pets and domestic animals as well, should they get tempted to try it.

California natives have some great nitrogen fixing natives that would be much more suitable to the Big Sur area, which is very important for saving California native plants.  If they don't want to bulldoze it or spray it, cutting it off at the soil level and bagging/hauling all cuttings off the property, then continuing to cut any new shoots as they appear.   Any plants are a huge source of spreading to other parts of the area and along with roadside growth, which costs taxpayers money in eradication.

Replant with natives that you can get great descriptions at Las Pilitas nursery website.


Here's from the Invasive Plants of California Wildlands:

French broom currently occupies approximately 100,000 acres in California (D. Barbe, pers. comm.). It displaces native plant and forage species, and makes reforestation difficult. It is a strong competitor and can dominate a plant community, forming dense monospecific stands. In an experiment in New Zealand French broom had a higher growth rate than any other broom species found in California, reaching an average height of more than 4.5 feet (141 cm) in two growing seasons. Since it can grow more rapidly than most trees used in forestry, it shades out tree seedlings in areas that are revegetated after harvest.

French broom foliage and seeds are toxic, containing a variety of quinolizidine alkaloids, especially in young leaves (Montlor et al. 1990). In some livestock, ingestion of plant parts can cause staggering followed by paralysis (McClintock 1985). Foliage can cause digestive disorders in horses (Parsons 1992). Infestations of broom degrade the quality of habitat for wildlife by displacing native forage species and changing microclimate conditions at soil levels. French broom is believed to be responsible for reducing arthropod populations by one-third in Golden Gate National Recreation Area (Lanford and Nelson 1992). It burns readily and carries fire to the tree canopy layer, increasing both the frequency and intensity of fires. French broom along roadsides obstructs views, requiring expensive ongoing road maintenance. This species establishes a dense, long-lived seedbank, making it difficult to eradicate.

Thanks so much for the reply Cristo.  I've heard many of the same things about it, and am definitely aware of how maligned it is in California!

I just can't help but feel like it MUST fill some ecological niche.  I don't think nature creates something that doesn't have some role in a healthy ecology (as much as I wonder about mosquitos, black widows, etc...). And I don't think French Broom is going away in California.  As much as some individual landowners might try to fight it, nature will continue to spread it beyond our reach.

I would love to hear anyone else's thoughts about how this "problem" could be in some way turned into a solution for California?

The State of California and the counties spend millions of dollars every year to get rid of invasive non-native plants.   If they didn't have to spend millions on broom and other invasive species, they wouldn't do it.  It's really important as people who care about agriculture, that we step back and see the much bigger picture.   Just because a plant grows somewhere, doesn't mean it benefits the ecosystem.  They are aware of what kind of features broom has, and would try to work with it, if it weren't so devastating to the existing flora and fauna.

The animals/rodents/insects/birds in a Mediterranean climate that doesn't get any summer/fall rain are dependent on their food supply from native plants.  They are down to the wire for food come October/November/December in a normal year.  Throw in a few years of  drought and many of them don't make it, and their reproduction decreases.  

When the imbalance of flora and fauna happens, the whole balance of the ecosystem weakens. If the existing ecosystem weakens then there will be no defense for invasive insects, which would devastate the food production/farming that the economy of California relies on.   California has the 8th largest economy In The World, not just of the other states, because of the food production not only in the Central Valley, but also along the coast where Brussels Sprouts and kale relatives can be produced in the summer because of the summer fog.  This food supply involves The Whole World, and would create a food shortage In The Whole World....this isn't very often talked about, but globally food production in California is crucial.

And if insects like these get food and reproduction help from non-native plants,  they can easily be transported from the coast to the Central Valley.  There are no agricultural inspections within the state, only at the state line.

   European Grapevine Moth
   Mediterranean Fruit Fly
   Asian Citrus Psyllid & Huanglongbing
   Red Palm Weevil
   Light Brown Apple Moth
   Shot Hole Borer
   Asian Giant Hornet

(From the California Department of Food and Agriculture)

Make Brooms!
Utilize Biden's latest make in america campaign to help fund a natural broom company in the US.
Gather the French Brooms and make natural french brooms.

...at least it's a positive idea.....

We have invasive honeysuckle here and its not as toxic but it does displace native plants.

I think goats can eat honeysuckle,  but my personal solution is making biochar.


I'm not sure that there is anytime  of year that a biochar operation would be safe where your at.

Regardless of how they are removed and used, a more vigorous plant would need to replace /suppress them.
I'm not sure what that plant would be.

I've been looking into invasives in California as well. We have a LOT of them.

Scotch broom is something I've been looking at. It's all over the place here. Like you said, it does well in soils with low fertility, it fixes nitrogen, and it does well on slopes without much water.

A species I just ordered a bunch of seeds of to plant near scotch broom is cercis occidentalis. It's native to the American southwest, and it has a lot of similar qualities as brooms. It fixes nitrogen and is drought tolerant, with the added bonus of having lovely flowers for all sorts of pollinators.

I'll be planting some near scotch broom as I find it - perhaps I'll come back here with an update in a year or two.

California is one of the most biodiverse regions on the planet. It is what they call a, Floristic Province. There are only 25 or Florensic provinces on the planet.

These are regions with high biodiversity and a unusual amount of endemic species, meaning species that aren't found anywhere else.

California has already lost countless endemic species to extinction  because they were displaced from their niches by invasive species and that has only just begin.

The redwoods are being over run with scotch broom, pampas grass, and acacia that were spread around by logging trucks Twenty years ago. Now they are every where and their emergence in that ecosystem has just begun, meaning what we are seeing is just the begining..

Forest that are trying to recover from logging now have faster growing acacias popping up. They are able to grow well in dark canopies so they grow right next to the redwoods and them shoot their branches over the redwood branches choking out their light while changing the soil chemistry (N fixation) and pH in the rhizosphere to conditions that better suits the acacia than the redwoods, not to mention spewing out massive amounts of seeds.
Acacia fill a niche in australia but here they are not kept in balance and so they are throwing everything out of balance. .

Pampas grass takes over entire meadows and ocean bluffs where now nothing else will grow all the while causing erosion because of their thick lateral root growth. Not all plants control soil erosion, some cause it.

I've seen areas along hwy one where they have been battling patches of scotch broom for 20+ years and it is still not under control, still spreading and like someone else already pointed out it is displacing species that already filled niches including wild life and covering the area so nothing else would grow and due to its poison seeds it will not feed the wild life that once flourished there.

Yes, nature produces things in a way that fills a niche, but sometimes if you remove that species from there and put it in a new ecosystem where nothing is holding it in balance it becomes something more like a cancer on a body, or a plague in a population than like a part of an ecosystem.

Having massive amounts of Nitrogen fixed into an ecosystem that does not depend on that will destroy that ecosystem. It can interfere with natural mychorizal associations and cause certain soil microbes that plants in that ecosystem depend on to shrink away because they will not longer thrive in those conditions.

All of these plants where brought to California to make the suburbs look nice. They did not arrive here naturally. They were ornamentals. Logging devastated the land scape and it's trucks spread the seeds along hwys and also deep into the forest on logging roads.

I've been cutting the broom down and using the branches to make tomato trellises / frames etc. It works great! I'm slowly trying to replace the patch we have with  elderberries, live oaks, and so on. I wouldn't leave the broom to just grow - our patch is quite well established and it's basically a dead zone, very few birds, no other plants underneath.

I'm very curious about this too, thank you for raising the question!

I spend a lot of time removing "invasive" plants for my work (questioning this term)--French broom, cape ivy, oxalis stricta, veldt grass.....I could go on. As a worker, it feels quite futile! I don't think we will "win" against these plants that have found an environment they thrive in....it's an uphill battle now, and every day they outpace us. I definitely don't think messing around with herbicides will protect biodiversity. And I am struck by how complex the natural world is, how little we understand it. These plants are living here, interacting with other plants and animals and microorganisms, evolving and digesting and reproducing and dying on this land somehow. How could that be a mistake? I feel fear and sadness about the anthropocene, all of the loss, death, and destruction--so far beyond what we have known, what we can imagine. And being inescapably part of it all. But to be honest, efforts (like mine....I understand the irony) to manually reverse this seem a bit delusional, a bit like being in denial rather than responsibility. Throwing ourselves into the labor of an impossible task, to distract ourselves from its impossibility.  I don't necessarily mind it so much...I find my impossible tasks rather fulfilling. Going out and fighting the evil invasive species gives me a predatory satisfaction, I confess! But I wonder if our efforts could be put to some better use. Maybe we need to wrestle with nature for a while. Maybe in 20 or 30 years it will be time to try something else. Or maybe we can grieve and fight all at once, or maybe we have to.

I've been looking online for arguments and different perspectives on biological nativism--if others have any resources on this, I'd be interested to hear, especially about science. Here's one blog I came across that has been feeding my engagement in this question: https://milliontrees.me/nativism-in-the-natural-world/

With appreciation and sincere questioning,
Caroline

There’s a great debate among permits about “fighting against” the spread of non-native and invasive species and “embracing” them and finding the niche. I’m not here to change anyone’s mind on the subject but I am familiar with many of the ones mentioned in this thread and have witnessed them taking over entire areas.  This is a great problem all over and like many of the mistakes us humans have made, eradicating these plant species from our landscapes is likely not something we can achieve. That pampas grass is horrible stuff. I’m guessing there’s a use for it (by the aboriginal peoples of Argentina) but all it seems to do here is spread. I know there’s supposed to be a variety that doesn’t spread but PLEASE, stop planting it as ornamentals. Short of implementing excavators, those rootballs are very difficult to remove. But there is some good news on the broom front. Now, I’m not familiar with the French variety (my battles have been with the scotch), but I’m assuming they’re are just as difficult to remove. Cutting them back will not get rid of them. Just make it harder to pull the root out. That’s the trick with many of these invasive. Getting the whole plant out, including the root. I have, independently, on my own property, and collectively, among the commons, successfully removed a great deal of scotch broom. The local, rural utility district I was Living in had a “remove the broom” day where they had these amazing tools available for folks to pull up the broom, root and all. Really easy. And talk about encouraging work. I was so inspired I went and bought one for my own shed. Still use it to this day. It’s super simple. I liken it to a t-post puller but it has slightly different action. Principle is the same. It provides the additional leverage needed to actually be able to uproot the plant. That’s it’s name, the uprooter. Here’s a link to the business that makes them.

https://www.theuprooter.com

I’ve actually met the guy and his wife. They make them themselves and have been very helpful. I see they have multiple sizes but I’ve only ever used the small one. If you are serious about getting rid of broom or other woody shrubs, this is your tool. I really can’t praise it enough. And I’m not a salesman, have no connection to the company. I am passionate about invasive and noxious plants. If you can’t justify getting one yourself, maybe you can get your local extension office or tool lending library to purchase a few to have available for the community.
Good luck with all your endeavors.