Not all plants are pleasant. The New York metropolitan region is chock full of non-native plants. What is a non-native plant you might ask? It’s any plant species that may look green and lovely, but can be quite destructive and foul. Many non-native plants come from other countries or regions of the world and have been introduced over time by people with little idea or sense to just how damaging these plants can be in a different environment.
The problem is that many non-natives plants compete with native species for habitat and food and often rapidly take over parts or whole ecosystems where indigenous plants or animals, some might be rare, need to survive. Non-native species are not natural and, as a result, often do not have natural predators, so their numbers will grow rapidly and be difficult and costly to control. Local deer and birds, for example, generally will not eat invasive non-native plants. Instead deer and birds will compete for a shrinking supply of berries or leaves from native plants, leaving the spread of non-native plants to grow uncontrollably.
Some non-native and invasive species that are the greatest threats to local biodiversity include tree of heaven, multiflora rose, porceliam berry, Norway maple, Japanese honeysuckle, and Asian bittersweet. These foul plants eliminate native plants in a variety of ways, including by blocking sunshine, sucking up water resources or climbing to the tops of trees until their hosts become top heavy and topple. These invaders disrupt what little valued habitat we have around New York Harbor.
One non-native plant species that really annoys me is garlic mustard, Alliaria petiolata. This too is an invasive and non-native plant. You can’t miss it now, the plant is flowering abundantly along roadsides, trials, and other disturbed sites.
Garlic mustard is originally from Europe. It was brought to North America in the early 1800s by famers for use as an edible herb, as it’s high in vitamins A and C. Crush a leaf in your hand and you will a notice a strong, distinctive smell similar to garlic. This is garlic mustard.
Although the plant looks nice at first, with likable white flowers and tall stalks, don’t be fooled. The looks are misleading.
Garlic mustard is dreadful. According to the New Jersey Agricultural Experiment Station at Rutgers University, garlic mustard poses a threat to native wildflowers like spring beauty (Claytonia virginica), trilliums (Trillium spp), bloodroot (Sanguinaria canadensis) wild ginger (Asarum canadense), as well as other native plants. The loss of plant diversity threatens native insects, including butterflies, because egg-laying sites and food sources may no longer be available.
Research shows that garlic mustard is allelopathic, meaning that it releases chemicals which can inhibit the growth of other plant species. Some researchers believe that these compounds can also hinder beneficial soil fungi (mycorrhizal fungi), which help tree roots take up water and nutrients.
The Cornell University Cooperative Extension tell us that garlic mustard has the potential to form dense stands that choke out native plants in the understory by controlling light, water, and nutrient resources. Plants most affected by these dense stands are herbaceous species that occur in similar moist soil forest habitats and grow during the spring and early summer season.
Other aspects of the forest ecosystem may be altered as well due to the change in the vegetative community tied to garlic mustard invasion. While the impacts to wildlife are not completely understood, altering the plant diversity can cause a change in leaf litter availability, potentially impacting salamanders. Insects, including some butterflies, may be affected through the lost diversity in plants and loss of suitable egg-laying substrate. These changes could have significant long-term effects.
Sadly, it’s not easy purging your neighborhood of garlic mustard. The Nature Conservancy states the plant is very difficult to eradicate once it is established in an area. It spreads rapidly and unfortunately, displaces native or other desired plants in a relatively short period of time. Each plant can produce thousands of seeds, which can be spread by wildlife, humans, water, or other means. An average plant produces 400-500 seeds that germinate readily in both well-lit and shaded environments. In the following spring, the garlic mustard will shoot straight up into a tall, slender flower with clusters of small white, four-petal flowers. Since the plant only flowers in the second year, the plants may appear less numerous in some years. This can be misleading, since the plants are just waiting to complete their life cycle.
Perhaps one of the best ways to remove the plant is to eat it. A website entitled, Eat it to Beat it, has quite a few garlic mustard recipes. Enjoy and don’t give up trying to remove the plant!