October Weed of the Month: Invasive Plants Escape from Cemeteries

What died in a cemetery but its offspring escaped alive? You guessed it - invasive plant seeds that escaped from floral arrangements. People have been using invasive plants in funeral arrangements for over a century in North America.

People used common tansy (Tanacetum vulgare) in coffins to repel insects and worms, including in the coffin of Harvard University's first president. After becoming a mainstay at New England funerals, people began to loath tansy due to its association with death. Seed from tansy arrangements could germinate in place or be moved by wind or water to germinate in new locations.

Two species historically used in funeral arrangements are oriental bittersweet (Celastrus orbiculatus) and teasels (Dipsacus spp.). With fruiting vines at peak color in the fall and early winter, Oriental bittersweet vines were made into bouquets and wreaths. Dried teasel seed heads were components of many attractive arrangements. Birds and other wildlife found these arrangements attractive and would eat the seeds and move them to new areas. A survey of historic cemeteries in Red Wing, Minnesota, found Oriental bittersweet in or adjacent to most cemeteries.

Sometimes, we move invasive plants inadvertently. Lucas Majure, then a Mississippi State University graduate student, and Charles Bryson, a USDA botanist, cracked the case of the blue sedge, Carex breviculmis, a species native to Asia and Australia. They found and identified the sedge in a few Mississippi cemeteries, a first for this species in the Americas. Evidence pointed to the sedge introduction by global visitors to the grave of Kelly Mitchell, Queen of the Gypsies. Twelve days after dying in childbirth on January 31, 1915, she was buried at Rose Hill Cemetery in Meridian, Mississippi. Her funeral was attended by over 20,000 Romanis, and people continue to pay their respects to this day. One or more visitors may have had seeds attached to their clothing or brought the sedge as an offering.

The introduction of these aggressive non-native plants caused ecological and environmental damage by displacing native plants and even damaging property. Tansy, oriental bittersweet, and teasels are noxious weeds in Minnesota and it is illegal to use them in arrangements.

Invasive plants became so problematic at our historic National Congressional Cemetery that 30 goats were hired to control them. Removing invasive plants enabled restoration of desirable vegetation. See the video Hungry Goats Graze Cemetery Grounds in Washington, DC.