Garlic mustard or Jack-by-the-hedge as it is commonly referred to, is a biennial plant that has been named an invasive weed. Its scientific name is Alliaria petiolata and it belongs to the mustard family called the Brassicaceae. This plant is a known invasive, and in this article we will talk about how to get rid of garlic mustard in your yard.
It is a weed that has invaded the U.S. for the last 150 years. The plant is native to Europe and some parts of Asia. It is believed that it was introduced to the U.S. for medicinal purposes and as a food. Garlic mustard was first grown in the U.S. around 1868 in Long Island New York. Its invasive nature has seen it grow as far as Washington, Utah and British Columbia.
How to Identify garlic mustard
Garlic mustard produces round, slightly wrinkled leaves in its first year of growth, which when crushed smells like garlic. The plant always flowers in the spring and produces cross-shaped flowers that are white in color. Once the blooming stage passes, the plant produces fruits in the summer.
In its first year, garlic mustard can be difficult to identify. You can identify it by crushing its leaves so that it produces the garlic odor. It is an herbaceous plant that has a tap root system which is whitish and thin. The leaves of the immature plant are dark green in color and are usually kidney-shaped, scalloped on the edges. The leaves measure around 4-6 inch (10-15 cm).
In its second year, the alternating stem leaves become triangular-shaped with sharper teeth. The leaves also tend to be smaller towards the top of the stalk. The mature plant also has a hairy leaf stalk. The plant still retains the garlic odor when crushed but the odor becomes less apparent with age.
The garlic mustard flowers arrive in spring and die out in the summer. The flowers grow from weakly or unbranched stalks. Garlic mustard fruit is in the form of a capsule that is slender and four-sided, called a silique. The fruit contains two sets of black and shiny seeds. They are dispersed when the silique splits open. A single plant can produce a hundred seeds and the seeds usually scatter several meters from the parent plant. This makes it difficult to get rid of garlic mustard completely.
Garlic mustard is either self-pollinated or cross-pollinated by insects. Self-fertilized plants are usually genetically similar to the parents. This makes them thrive in the environments that the parent plant survived.
Alliaria petiolata blossom
Natural habitat
The plant usually grows in many areas around Canada and the U.S. It is most common in disturbed areas, and can grow in wooded areas, swamps, ditches, and roadsides. Garlic mustard can also be found in the undergrowth of disturbed forests.
Reports of garlic mustard in the US
Uses of garlic mustard
Garlic mustard has been used as a spice in Europe for a very long time. In the 17th century, the British recommended it in the flavouring of salt fish. The herb is also known to strengthen the digestive system. It can be eaten raw and can be used to prepare a salad.
The herb is known for its medicinal properties. The leaves and stem of the herb can be used to treat asthma. They can also be used as antiseptic. Garlic mustard leaves have been found to be particularly great in curing eczema and bronchitis. The herb can also be used to inhibit the growth of typhoid bacteria, therefore, controlling its spread.
Garlic mustard can be used to make yellow dye. In some areas, it is grown to help in erosion control.
Why is garlic mustard invasive?
Garlic mustard is a threat to the ecology of the forests in the Midwestern and Eastern U.S. It has the capability to dominate the undergrowth of the forests in a relatively stable ecology. The plant also displaces the native plant species. Once it enters an area it becomes almost impossible to get rid of garlic mustard. It establishes itself in an area, and within two years it invades the area until it dominates it. This leaves no chance for other plants to survive in the ecosystem.
Trees that are at their formative stages, especially the oak, can’t compete with the herb. Wildflowers such as bloodroot, Dutchman’s breeches, hepatica, toothwort, and trillium also can’t compete with the herb. The small animals and insects that depend on these plants are usually the victim once this invasive weed takes control of an area, because they are deprived of their food and habitat.
Garlic mustard also poses danger to butterflies. This is because its leaves which the butterfly larvae feed on produce chemicals that kill the larvae. Butterflies are very critical members of the world’s ecosystem since not only do they beautify the environment, but they also take part in the pollination process of plants. Most plants produce through pollination, therefore if the butterflies are eliminated it will lead to massive crop failures. This means that there will be food insecurity because the yields will not be enough to sustain people and livestock.
Area of woodland being invaded by garlic mustard
How to get rid of garlic mustard?
The herb is nearly impossible to control once it invades an area. This does not mean that it cannot be controlled or removed from an area completely. There are various ways to get rid of garlic mustard in your yard.
Biological control
These are methods whereby living organisms such as insects, nematodes, bacteria, and fungi are used to inhibit the growth and invasion of the weed.
There are several types of European weevils that can be used to get rid of garlic mustard. The weevils are of the genus Ceutorhynchus. This provides an exciting and sustainable long term control method for the weeds. These weevil’s larvae eat the garlic mustard at different stages of its growth and development. This method, however, is not yet fully tested because there are fears that the weevils, once released, will feed on the non-target native plant species.
The main weevils are Ceutorhynchus alliariae Brisout and Ceutorhynchus roberti Gyllenhal. They have proven to be the most successful in attacking the garlic mustard plant. The two weevils share the same features and occupy the same niche in the host plant. Adult weevils feed on the leaves while the larvae develop on the stem of the plant. This is instrumental in the destruction of garlic mustard because the leaves and the stem are very critical in the plant’s life.
Chemical control
This is the use of herbicides to get rid of Garlic mustard. The use of herbicides should only be used according to their manufacturing manual. Protective gear and equipment are also essential in the application of the herbicides. There is the use of spot treatment where the herbicide is only directed to the target plant to avoid harming the non-target plants. Caution should be exercised during the spraying of these herbicides because indiscriminate spraying of the plants can affect the other desired plants, therefore, giving a chance to garlic mustard to actually thrive.
The herbicide used in this method is called glyphosate. It is an indiscriminate herbicide that destroys any plant that it comes into contact with. Applications can be timed around early spring when other plants have not sprouted. It is also highly recommended to spray in the late fall to reduce the damage to the desirable plants.
Mechanical control
These are the physical methods that are used to get rid of garlic mustard. These methods are usually effective if they are accompanied by other methods or if the infestation covers a smaller area.
Cutting
This method involves cutting the flowering plant by hand, lawnmower or string trimmer. This method requires that one cut the plants low enough so as to destroy the stem, since if the plant is still flowering, the stems can still be able to sprout and produce seeds. The cutting should be repeated severally during the season and the consecutive years to completely remove garlic mustard.
The disadvantage of this method is that it is only effective if the invasion covers a relatively small area. The use of lawnmowers and string trimmers destroys the desirable plants, therefore, encouraging the growth and manifestation of garlic mustard.
Prescribed burning
This must be done by a professional. It is effective for medium to large infestations of garlic mustard. Research shows that dormant season fires do little to suppress the herb. On the other hand, growing season fires are effective in eliminating the weed but it poses a danger to the native and desirable plants. One dormant season burn increases the garlic mustard count in the next spring but repeated burning helps in keeping the garlic mustard at controllable levels. It is also great for the regeneration of the vegetation in that area.
Grazing
The herb is usually edible and not toxic, therefore animals can graze on it. Animals usually avoid it because of its garlic-like odor but will resort to it when the desired vegetation is lacking. Animals should feed on it before flowering so that seed production can be controlled. This method can only be effective if it is used with another method. It is however not great for dairy cows because the milk will have a garlic-like smell.
Conclusion
In conclusion, even though the plant is edible and it has many nutritional benefits, it has other disadvantages that outweigh its use and importance. Garlic mustard disturbs the ecological balance and it competes with the native plants. It is considered an invasive weed and therefore proper control methods should be used to get rid of garlic mustard. It greatly interferes with the pollination process by killing the butterfly larvae. This is because butterflies are instrumental in the pollination process that helps plants make food. This food is then consumed by other organisms such as humans and livestock and that means that this weed is endangering the lives of people and livestock because of reduced yields. Controlling and eliminating garlic mustard also takes a considerable amount of time and resources which raises the production costs in farms and forests.
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