The Basics About Scotch Broom for Gardeners.
From the Broombusters Invasive Plant Society
As Master Gardeners, you understand how each species of plant has unique needs and certain growth patterns. Let’s look at Scotch broom. It is a titan in the plant kingdom, and unfortunately, it is wreaking havoc on ecosystems all over the world. When it is introduced into a new area, it looks around and murmurs, “Give us a minute. We’re taking over this place!” Sadly, it does!
How can it be so aggressive? Scotch broom is a woody weed, not a tree. A mature plant produces 18,000 seeds which explode from the brown seed pods in summer. The seeds remain viable for over 30 years. So, whenever the soil is disturbed, those seeds sprout, and the plant continues to spread. It can grow over 3 meters, smothering native species and young trees
A 2021 study by ESSA Tech for Invasive Species Council of BC found that Scotch broom is the invasive plant doing the greatest harm to species at risk in BC. It is the Top Offender of biodiversity in BC, harming not just native plants, but also terrestrial mammals, insects, birds and bees.
Scotch broom is not only a problem on the Pacific Northwest, but Australia, New Zealand, South America, Croatia, and on and on. Sadly, it is almost always introduced by gardeners. In 1850, Captain Walter Grant brought 3 seeds to Sooke. The nightmare we are experiencing now is a result of him missing the familiar plant from Scotland. (Lesson learned!)
To understand how to control and kill Scotch broom:
Broom spreads by seeds, not by roots. If you cut broom level with the soil or below, it will die in the drought of summer. The roots do no harm. But if the cut is ½ inch above the soil, buds may sprout again. Cutting is best completed before the seed pods form, about 4 weeks after blooming starts, so that we don’t spread the seeds.
Big Broom dies easily. Just cut off all the green branches. You don’t even have to cut to the ground; just peel back some of the bark. If you just can’t get to the single root under many sprouts, beat it up with a hatchet. Mangled stems are often enough to kill the plant. We cut in bloom because the energy of the plant is above the ground, so the roots are at their weakest. And then there is the heat of summer! The technique works. Where Broombusters are cutting broom, it is disappearing.
Broombusters Invasive Plant Society has been cutting down broom since 2006, with now over 600 volunteers cutting broom up to 7000 hours, all over the islands and Sunshine Coast. The website has videos and important information. Find out where there are groups, or contact us and start your own.
Broombusting is community weeding! We hope that you can join with Broombusters, with others, or start your own project. We simply cannot let this aggressive bully smother our native plants and young forests.
Cut Broom in Bloom. www.broombusters.org
Submitted by Joanne Sales, Executive Director of Broombusters
