|Problem or Solution?|
Scotch broom has been the bane of most folks at one time or another. Readily occupying newly cleared land, gardens or cultivated fields, with massive yellow blooms that are beautiful and torturous to those with allergies to its abundant pollen. A huge amount of foliage that rapidly springs forward, clogging industrial sites, and roadways, seemingly impossible to eradicate or even control. I used to think along these lines, that the introduced species was to be destroyed, almost purchasing a Scotch Broom removing tool and going into business trying to help people get rid of this beastly plant from Europe. Now, with Permaculture, I see the problem as the solution, and have some concepts how this plant can help speed succession and create abundance in the place of spraying this plant to control it.
Scotch Broom is native to Northern Africa and parts of Europe, and was introduced to Virginia in the United States in the early 1800's for use as fodder for domestic sheep. I was considered invasive in that area by 1860. From there it has spread rapidly across the coasts of America, not hardy enough to tolerate the cold climates of the North American interior. Scotch Broom was introduced to Vancouver Island in 1850 as an ornamental, and from three surviving plants, has spread over most of the island in that short time. However deliberate planting of Scotch broom by the British Columbia Ministry of Highways have accelerated the spread of this "weed" during the last 60 years. Because of its deep tap root Scotch broom is great at loosening soil, "mining" nutrient deep with in the sub-soil. It can grow prostrate(laying down") or upright, depending on light conditions. When prostrate it takes the niche of ground cover, protecting the soil from direct sunlight and wind, assisting with preserving moisture.
Scotch Broom, while "introduced", is a pioneer species. Most "weeds" are pioneer species, the plants that work for Mother Nature. They are the first to germinate, from seeds that may lay dormant in the soil for decades. Mother Nature abhors bare soil, nearly instantaneously sprouting fresh growth in newly tilled soil. The bane of conventional gardeners, if we understand these cycles, we can harness this power to create abundance and slow the growth of undesirable species. Dandelion, chickweed, comfrey, clover, and alder are some that come to mind. Many of these species fix nitrogen from the atmosphere to the soil via bacteria located in nodules on their roots, mine deep minerals, create biomass(think mulch), act as ground cover, and attract insects and other wildlife with food and flowers. Mimicking the characteristics of "weeds" can be a wonderful technique to home gardeners.
I became aware of the power of Scotch broom from reading Miles Olson's book "Unlearn, Rewild". He has a chapter called Succession, and in this section he describes a slope that was destabilized and slid to the valley bottom. Within a few years that slope was covered in vigorous Scotch broom, holding the slope, nutrient loading the soil and creating a habitat for other species to succeed in. This information was a little mind altering to myself. Newly grasping Permaculture concepts at the time, I could finally understand the "Problem is the Solution" principle. Just because a plant is introduced and "invasive" it is only filling a niche, because mankind has done something to alter Mother Natures perfect design.
How do we attempt to utilize a problem and turn it into a solution. While I have not attempted the following techniques, the concept is based on science and natural succession. We can easily speed it up with a little technology, a wise use of fossil fuels and manpower to create a low maintenance, abundant system.
The simplest, least energy involving technique, in my mind, is called "Slash". Slash involves the chopping of biomass, laying it down as it was cut. The pile of dead shrub will protect the soil from evaporation, and smothering the new broom from springing up. Roots of the old plants acting to maintain soil stability, and rotting in time, building topsoil. The key to using a pioneer species to succeed wanted plantings, is to quickly add the plants that will fill the role of the removed one, or the cycle will repeat again. Cover cropping with clovers and legumes will fix nitrogen. Trees like Alder and Black Locust fix nitrogen too, also creating biomass and fuel wood. Along side these supporting plants we also put in the main crop of food producing trees and shrubs. Running animal through the disturbed land before and after slash would also aid in the fertility of the soil, creating a yield of meat, eggs and milk. Pigs, goats, sheep, cows, and chickens would have a variety of impacts on a Scotch broom field, disturbing soil, eating seeds and stomping the slash along with manuring the site.
There is another technique in Permaculture similar to slash called "chop and drop" which is using support species, bolted annuals, or weeds as mulch. We take the unwanted biomass and chop it into small particles, with pruning shears, lawnmowers or tree chippers, and place it around the plants we want to keep, our main crop species. This protects the soil, hold moisture, slows weed growth, add nutrient and creates habitat, plus many other micro relationships. This mimics leaf drop and branch fall after a wind storm in a true forest. We can take an area infested with Scotch broom, chop it down, and using a tree chipper, turn it into a large pile of mulch, that can be then used as a mulch once the main species are planted. I would add that doing this in the winter, or spring would be advantageous, keeping the spread of seeds down. I also would not recommend taking this mulch away to another site, unless perhaps, it could be hot composted to kill any remnant of seed. We don't want to spread this plant on purpose.
Another idea I had would be to use the biomass of broom for the base of Huglekultur mounds. Burying it deep under soil and compost to keep any seeds dormant. Again tractoring chickens through the slashed piles would be an asset to seed removal and manuring. A pioneer species is quick to break down into loam, to create fertility and water retention. Placing the chopped broom on contour would add to its water slowing abilities on damaged landscapes. Most grounds we find Scotch broom on were subject to erosion, so we must make sure that removing the plant does not re-create this wash. This will just cause the broom to come back.
I love conceptualizing different land healing techniques. While I have no proof that this works personally, the use of Mother Natures cycles will work. There is no need, in my opinion, to use noxious chemicals on this planet for anything, since we have a perfect model just outside our door. Mankind just needs to get out of the way, or we will be rolled over by it. I would love to help someone who has a broom problem to restore vitality to the land and turn it into a productive landscape.