WVU Core Arboretum Garlic Mustard Pulling Information

garlic mustard 6Native, wild-growing spring ephemeral wildflowers like bluebells, trilliums, and larkspur are one of our most wonderful assets here at WVU Core Arboretum.  Growing among our treasured native spring ephemerals, however, are some invasive plant species.  These invasive species, if not controlled, threaten the future of the native plants that many people come here to appreciate.  Control typically involves removal of plants to keep invasive plant populations at a low, manageable level.  One of the invasive plants that we manage is garlic mustard (Alliaria petiolata)

What is garlic mustard?!

Garlic mustard (Alliaria petiolata) is a plant in the Brassicaceae family (like broccoli, cabbage, cauliflower, kale, etc.) that was brought to the US many years ago as a plant used in food and medicine.  Although it is useful to people, the plant unfortunately escaped cultivation and invaded forest ecosystems.  It is capable of growing under the same environmental conditions as our spring ephemeral wildflowers, and it very effectively replaces them over time through direct competition for resources and release of chemicals that are toxic to other plant growth.  Garlic mustard is a biennial, meaning that each plant lives for two years.  The first year it exists aboveground as a basal rosette, a low circular patch of leaves without any real vertical stem.  During this first year of growth it accumulates resources and stores energy in a large root.  In early spring of its second year of growth, the plant quickly grows tall, leafy stems topped with heads of white flowers that produce very many seeds.  These seeds will sprout over the next several years, meaning that one plant causes many years of problems. 
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Garlic mustard basal rosettes are pretty hard to locate, but the second-year, flowering plants are easily found once they start to get pretty tall.  These are the plants that we pull.  It is important to get the entire root, or it will just regrow (some people carry an old screwdriver or similar tool to dig around a bit and loosen them before pulling).  It is also important to remove all pulled plants from the premises and to do all pulling before the plants begin dropping seeds.  This means that we have a pretty tight window in which to work:  garlic mustard pulling season.  We try to be very thorough and remove all plants, but plants and roots are always missed and seeds are always being re-introduced, meaning that this is likely to be an annual event for a long time.  The task should diminish in size, however, as we slowly reduce the seed bank present in the soil.  We bag and remove all collected plants, and they are composted in a sacrificial area away from the Arboretum or disposed of in the municipal waste stream.  All help is greatly appreciated!

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