After much anticipation the first attempt at Garlic Mustard control took place on the Blue Mountain Club’s Timpson property.
On May 22, 2025, a group of hardy volunteers including our Conservation Ambassadors, braved the inclement weather to take on a section of the Timpson property which was being taken over by Garlic Mustard plants. There were over a dozen large garbage bags of Garlic Mustard collected and taken away for solarisation; a method of using the sun’s energy to produce high temperatures, which can destroy the weed seeds.
Garlic Mustard is an adaptable, aggressive, biennial (2 year life cycle) herbaceous plant. The first-year plants produce a rosette of dark green, kidney-shaped leaves with scalloped edges:
The second-year plants grow a stem 30-120 cm (11.8-47.2 in) high with triangular, alternate, sharply toothed leaves:
The lower leaves are kidney-shaped and up to 10 cms across and the plants produce white flowers with four small petals in May.
Garlic Mustard plants should be pulled before they go to seed:
Garlic Mustard seed pods. seeds are dropped as these dry out.
The control of Garlic Mustard is very important as it forms dense monocultures that reduce the biodiversity and aesthetic value of natural areas. The effects of Garlic Mustard on ecosystems are long-lasting and may permanently alter forests, even after removal. It releases allelopathic chemicals that change soil chemistry and prevent growth of other plants. It outcompetes and actively displaces native woodland plants.
Within the Blue Mountains Garlic Mustard grows pretty well everywhere and spreads quickly along roadsides, trails, and fence lines. The main pathway for seed spread over long distances is through humans, pets and wildlife inadvertently carrying seeds to new areas on boots, clothing or fur. Hiking trails such as the Bruce are also a major corridor for seed dispersal and the spread of Garlic Mustard plants. It only takes one plant to start a new population.
It will be important to continue with repeated pulling of the same area for at least 5 years to ensure that the seed bank is depleted. If only done once, there is the likelihood of increasing Garlic Mustard densities by stimulating seed germination through soil disturbance.
