Jun 22, 20232 min read

Common and Glossy Invasive species of Buckthorn in Ontario

Invasive Buckthorn Species

In Ontario, There are two types of Invasive Buckthorn species; the common Buckthorn (Rhamnus cathartic) and the Glossy Buckthorn (Frangula Alnus). These two species of Buckthorn are some of the most dangerous invasive plant species in Ontario, as they are prone to invading different habitats and causing significant harm to local ecosystems (Invasive Species Buckthorn - NVCA, 2017).

Characteristics of Buckthorn

Buckthorn plants typically grow between 2 to 3m tall. In Common Buckthorn we can find fine teeth on the leaves whereas on glossy Buckthorn the teeth leaves tend to be smoother. We can distinguish common buckthorn from other species of buckthorn by identifying a thorn at each branch. Buckthorns also grow black berry’s during the summertime. Common Buckthorn can be found near roadsides, riverbanks, forests, and farms, and as previously mentioned glossy buckthorn is typically found in wetlands where they are an invasive species (Invasive Species Buckthorn - NVCA, 2017).

Why are invasive Buckthorn species of Concern?

Common Buckthorn in specific is capable of acting as host for fungus that causes oat crown rust. Oat crown rust (Puccinia Coronata) has detrimental effects on plants such as leaf damage, stunted plant growth, reduced photosynthesis and reduced forage quality. Oat Crown Rust can also result in stunted root systems, and lack of drought tolerance for plants. All together, this ultimately impacts the success of crops and therefore impacts food supplies (Oat Crown Rust, 2017).

Both species are capable of adapting and thriving in numerous natural conditions and have the ability to create strong bushes that invade the habitats of native species. Not only do Buckthorn invade the habitats of native species but they also have the capability to alter the soil’s nitrogen levels to better suit its own needs and through this can decrease the health of the surrounding species. Buckthorn species are able to reproduce quickly through seeds as birds often spread the Buckthorn seeds through the black berry fruit (Invasive Species Buckthorn - NVCA, 2017).

Figure 1: Glossy Buckthorn berry leaves (invasive Species Buckthorn - NVCA, 2017).

How can we reduce the effects of Buckthorn?

Buckthorn shrubs can be removed and the earlier the plants are removed when identified the better. It is ideal to remove the plants when the surrounding soil is damp and is ideal during October when other native species will not be disturbed. Through this process, it is crucial that the entire shrub is removed as if it is not entirely de-rooted the Buckthorn can re-sprout and reproduce in even larger amounts (Invasive Species Buckthorn - NVCA, 2017).

Figure 2: Common and Glossy Buckthorn characteristics (Invasive Species Buckthorn - NVCA, 2017).

Other Tips to reduce the Spread of Buckthorn

Dispose of invasive plants in the garbage. Do not put them in the compost or discard them in natural areas.
Discarded flowers may produce seeds.
When hiking, prevent the spread of invasive plants by staying on trails and keeping pets on a leash.
Gardeners are also advised to utilize native and non-invasive species when gardening.