Blog & News

Volunteer Spotters contributing to what we know about invasives on PEI! (archive)

Published on Wednesday August 5, 2015
Authored by PEIISC

Since our first Spotter’s Network training session in July, we have received an increased number of invasive species reports. We are learning that some of the species that we believed were quite rare are actually more common than we thought.

One of those species is Garlic Mustard (Alliaria petiolata). Before July, we knew about 2 locations of Garlic Mustard on PEI. We now know of 4 different sites. This is the Spotter’s Network in action!! Volunteers are submitting their reports and we are learning more about the distribution of these invading species on our island.

Now, a little more about Garlic Mustard…

It’s a biennial, meaning it has a two year life cycle. First year plants form leafy rosettes of kidney-shaped leaves close to the ground. First year plants don’t flower. Second year plants can reach 1m in height and have triangular-heart-shaped leaves. Flowers are small, white, and cross-shaped with 4 petals, and occur on stalks in small clusters. Flowering occurs continuously throughout the season. If left to go to seed, seeds can remain viable in the ground for 5 years.

Garlic Mustard leaves have a strong garlic smell (apparently they make a great pesto!).

The issue with Garlic Mustard is that it is very shade tolerant and can completely take over an understory, outcompeting native species for light, nutrients, and space. Garlic Mustard is also allelopathic, meaning it can release chemicals that inhibit the growth of mycorrhizal fungi and native plant species.

If you come across Garlic Mustard in your travels, please be sure to submit a report!

Attached images:

Volunteer spotters
First year leaf
Garlic mustard stalks
Second year leaf