Have you ever seen the invasive Montpellier broom (Genista monspessulana) in Cape Town? The invasive species is native to Europe. High seed production and long-lived seeds make eradication of established populations very difficult.
The species is currently listed as Category 1a in the National Environmental Management Biodiversity Act (NEMBA) Alien and Invasive Species (AIS) Regulations (2014). Category 1a species must be removed if found anywhere in South Africa.
How does Montpellier broom reproduce?
- Montpellier or French broom is a woody, tap-rooted shrub that reproduces by seed.
- It doesn't spread vegetatively from its roots, but plants can survive cutting and tend to re-sprout from the crown when cut or burned.
- Seeds are produced in hard, dry legume pods that burst open when mature.
- Seeds are generally dispersed close to the parent plant unless soil is moved through erosion, flooding or other means.
- Similar to other broom species, French broom seeds are hard and long-lived.
- Plants can produce over 8000 seeds a year.
Historical discovery of Montpellier broom in Cape Town
In 2013, the Custodians of Rare and Endangered Wildflowers (CREW), a citizen science programme, supported by the Botanical Society of South Africa (BotSoc) found a population of Montpellier broom on Vergelelgen Wine Estate.
- The plants were discovered in September 2013, when CREW they found a yellow pea in flower. At the time, the CREW team were uncertain of their identity.
- Working through the numerous identifications and backlog, they finally posted the plant on Ispot in March 2014, where it was identified as Genista monspessulana, commonly known as French or Montpellier Broom.
- SANBI’s ISP (Invasive Species Programme) identified the plant and alerted the City of Cape Towns Early Detection and Rapid Response Unit.
- Together with CREW and Vergelegen Environmental managers we went out to site to confirm the identification of the plant.
- The CREW volunteers assisted in hand pulling all the small individuals and the EDRR team went out to site a week later to remove the remaining large plants.
- CREW volunteers removed the plants by hand pulling and scouted the area for more plants.
The population was found next to one of the farm roads, far away from houses. The origin of these plants is not known, but what is worrying, is that these plants were growing in and among the fynbos. Scouting the surrounding areas we found that this population did not seem to have spread far at all, but to be certain, we need to return when the plants are in flower.
The site was monitored and a follow up site visit was planned for spring when the plants were in flower to see if any individuals were missed. Regular follow ups ensured that this population was removed.