In February, the Rare Plant Conservation Program (RPCP) enjoyed the assistance of the University of South Florida Alumni Association of Polk County. The Association invites its alumni to help the community through volunteer events to foster and maintain a lifelong relationship between the university and its alumni, to inspire current and future alumni, and to advocate for public service. In February, six USF alumni helped RPCP staff maintain the ex situ National Collection by weeding out invasive natal grass from the growing bed area, which contains the accessioned collection of endangered species.
Rose Natal grass (Melinis repens) poses a significant problem in both the growing beds and the natural areas of the Gardens because it is highly invasive, outcompeting native plants for resources like light, water, and nutrients. This leads to the displacement and decline of endangered plant species being preserved in the National Collection beds and native species in the natural areas.
Rose Natal grass is native to South Africa, the Arabian Peninsula, India, the Seychelles Island, and the Canary Islands. It was introduced to Florida in 1875 as a forage plant for cattle. Lacking nutritional value, it failed as forage for cattle but continued to be distributed as an ornamental plant. However, it is a prolific seed producer and has spread rapidly throughout Florida’s natural areas, thriving in Florida’s subtropical climate and sandy, well-drained soils, threatening native species. It is now listed as a Category I invasive species in Florida.
Burning and mowing will not provide control of natal grass. Herbicide spray can be effective but must be applied before flowering and seedling, performed at regular intervals thereafter, and with complete coverage. Uprooting entire plants by hand, wherever this is possible, remains the most effective means of control.
Protecting the precious rare species in the National Collection from threats like natal grass is a full-time occupation and requires the help of dedicated volunteers. The USF Alumni Association of Polk County volunteers were the perfect group to help protect the rare plants in the Collection. For three hours one morning during their visit in February, they stepped up to the task of natal grass removal with care and enthusiasm and removed several large contractor bags stuffed full of natal grass plants and seeds, for which the RPCP is extremely grateful.
Article by Cheryl Peterson, Bok Tower Gardens Conservation Program Manager.