Home » Gardening » Trees and shrubs » Scotch broom, is it invasive or not? Depends where…

Scotch broom, is it invasive or not? Depends where…

Clump of invasive scotch broom, here in its native range
0

Scotch broom, although a delightful shrub, is not to be planted everywhere. This European native fought with other plants to secure its own living space in its native habitat. This gave Cytisus scoparius strong resilience and adaptive power that makes it very invasive in many other places!

In many states in the USA, it’s declared an invasive weed. With the maps below, you can check for yourself whether or not to plant it. Sometimes local governments even have programs you can join in on to help eradicate the scourge!

Native and Invasive ranges of Scotch broom

Native to – Europe

Invasive in – Oceania, North America, East Asia, portions of South America, Central Asia, South Africa

Native range map of Cytisus scoparius

Scotch broom was first admired by botanists for its bright yellow blooming and dense growth. Horticulturists happily offered the plant, and others of the Cytisus family, for purchase to their customers for landscaping purposes.

However, in the late 20th century, awareness rose about how invasive the plant could be. There wasn’t even any point in letting it grow, since the shrub doesn’t make for good fodder. Additionally, it is rated as an extreme fire hazard: a few licks of a candle and the entire shrub might ignite in dry weather.

Many state and national programs today try to eradicate this threat to local biodiversity. In California, a particularly fire-prone state, fire prevention plans even call for pulling the plant out wherever possible.

Map of where Scotch broom, Cytisus scoparius, comes from

Native range: Austria, Belgium, Belarus, Bosnia and Herzegovina, Czech Republic, Croatia, Denmark, France, Germany, Hungary, Ireland, Italy, Lithuania, Kosovo, Moldova, Montenegro, Macedonia, the Netherlands, Norway, Poland, Portugal, Romania, Spain, Serbia, Sweden, Switzerland, Ukraine, United Kingdom

Invasive range: Australia, New Zealand, Canada, United States, Japan, Chile and Argentina, India, Iran, South Africa (the country)

In green, on the map below, you can see where the plant is native to. Even within these areas, however, it is sometimes listed as an invasive weed because it can take over land from less combative species.

Native range of the Cytisus scoparius shrub, Scotch broom

Sightings of Scotch broom in the USA

The University of Georgia manages a mapping system to report sightings of scotch broom across the United States. The Early Detection and Distribution Mapping System program makes it easy for volunteers to signal the presence of this plant with accurate localization.

Here is the most recent version of the map for Scotch or Scot’s broom:

Status, legality and regulations about Scotch broom

In the United States, Scotch broom is especially problematic along the West Coast. Weather patterns there often lead to dry seasons and fires wipe native plants out. Then, on bare ground, Scotch broom sprouts and dominates all other native plants within a few years.

On the following map, you can check whether the plant botanists call Cytisus scoparius is officially registered as a weed in your state.

Smart tip to deal with invasive Scotch broom

Don’t fall for the trap of burning off patches of Scotch broom. Seeds are fire-resistant, and it will sprout back much faster than other native plants! Better to pull them out or prune them to a stump once a month until the root system is drained and dies off.


Sources (maps)

GSID, as of November 2nd, 2020
EDDMapS


Image credits (edits Gaspard Lorthiois):
CC BY 2.0: Christian Ferrer
CC BY-SA 3.0: Smurfy
A comment ?

Your email address will not be published. Required fields are marked *

Your reactions
  • Tammy wrote on 27 April 2023 at 15 h 49 min

    I’m trying to find out if ALL Scotch Brooms are invasive. I just purchased Apricot Gem and now I’m wondering if I should even plant it. Thanks in advance for your help.
    CYTISUS X BOSKOOPII ‘APRICOT GEM’ SYN. CYTISUS ‘APRICOT GEM’

    • Gaspard wrote on 29 April 2023 at 8 h 44 min

      That’s a good question, Tammy. From my experience, nearly all Cytisus are prolific seeders, which makes them invasive. Hybrids like C. x Boskoopii tend to have less seeds and their seeds aren’t as fertile, but nonetheless it isn’t a completely sterile variety. It’s difficult to get sterile cultivars with plants that aren’t dioecious (a dioecious plant is either male or female, but not both – so having males means it won’t bear seeds).

      A species of cytisus known to grow less seeds is Cytisus multiflorus, but it still does bear quite a lot.

      If you haven’t yet planted it, I’d perhaps recommend calling the nursery or store where you bought it to check with them how high of a risk it is. For instance, pruning after the blooming is over will remove any seed pods that might be forming. And in case they realize it isn’t a good choice to sell the plant in your area, they might be able to switch it out with another dwarf shrub that is either native or non-invasive.

      • Jude wrote on 15 May 2023 at 13 h 58 min

        Hello…We live in northern Virginia just outside Washington, DC, and purchased a beautiful 1.5’ tall orange/red flowering Cytisus from a nearby Home Depot. It’s not labeled multiflorus, and neither the store nor the store personnel identified that it’s invasive or problematic. We planted it in our front yard bed area facing south very near a mature 20’ Japanese red maple.

        They look fantastic together, and now we just found the Picture This flower identification app and were checking it to see what flowers could go in this area and are reading that we may have added a dangerous plant. Have we just made a horrible mistake?

      • Gaspard wrote on 20 May 2023 at 10 h 14 min

        Well, it certainly wouldn’t be the first time mistakes are made! I’d recommend pruning and deadheading the shrub once flowers have wilted away. That will reduce the amount of seeds going around. In a way, it’s a bit sad that garden centers aren’t yet able to sell exclusively native or non-invasive plants.

  • Jim Brannigan wrote on 21 May 2021 at 7 h 14 min

    I’ve finally given up and must admit that I really admire the the Broom.
    I am a Scot, living on Vancouver Island and over this past number of years have done my bit to try and eradicate the beautiful shrub but it just keeps coming back. So now I have goats and bees both of which thrive on the gorgeous bush.
    I have no doubt that pigs would make a meal of it too.
    The debate in North America seems to only have one side and no one seems able to find a use for it.
    Take a second look.
    Didn’t we just go through all this with the dandelion?

    • Gaspard wrote on 21 May 2021 at 7 h 53 min

      Hi Jim! I’m the first to agree with you that this broom is definitely useful wherever it might be planted! Broom is wonderful for pollinators, beautiful and when you get down to it you can use it as fodder for less picky animals than cows and horses, house equipment, basket-weaving, water filtering… the list goes on and on!

      The notion of invasive, though, isn’t meant to disparage the plant. It’s meant to protect the local fauna and flora. Admittedly, it’s a bit of a hypocrisy when we go after a plant instead of curbing urban land grab, vast parking expanses, and the like… hard to get priorities straight. But broom has been proven to squash more fragile local species to the point of extinguishing them in some parts, so that’s why it’s definitely an invasive plant. Dandelion, for instance, doesn’t have that power to actually “replace” anything, so at worst it’s simply a “nuisance”.

      The approach of trying to keep an environment as pristine and “pre-human” as can be is valuable, though, since for each ecosystem there is trove of secrets that we haven’t yet unlocked. Invasive plants tend to render landscapes and plantscapes more homogenous and uniform, which decreases those opportunities in a way.

      The future of globalization is when each is proud of differences as much as being appreciative of what unites us, and the way we consider the environment mirrors our behavior as human beings. As you’ve already noticed, simply contemplating nature at work, even invasive nature, is the first step in this endeavor. It should definitely be a step frenzied eco-activists should take instead of immediately roaring with rage…

      I appreciate your insight, thanks for sharing your thoughts! It must indeed feel harsh to pull out a fellow Scot when it’s just trying to make its own way in the world and help others out :p