Green shrimp plant – friend or foe?
By Ralph E. Mitchell
The green shrimp plant has become a common weed post Hurricane Charley in our area. Ruellia blechum, or green shrimp plant, is a weed that entered my yard right under my nose. Also known as Browne’s blechum, the green shrimp plant is a perennial that may already be in your yard.
I first noticed the green shrimp plant in a small nook near a fence in my yard and wondered what this odd plant was. The flowering bract was most noticeable as if does remind you somewhat of the segmented body a green shrimp. The plant itself it really nondescript with opposite simple, slightly toothed green leaves. It roots tenaciously into the ground and often snaps at the base leaving the roots and part of the plant intact. At this point in time, the green shrimp plant has spread throughout my yard, mostly in landscape beds, along fence lines and around trees. In mowed areas, it most likely just becomes part of the broadleaf weed collection that I involuntarily maintain in my lawn. So, the green shrimp plant is both a weed and a CATEGORY II Invasive plant which means according to the Florida Exotic Pest Plant Council (FLEPPC) that “Invasive exotics that have increased in abundance or frequency but have not yet altered Florida plant communities to the extent shown by Category I species. These species may become ranked Category I if ecological damage is demonstrated.” With this in mind, what can you do to manage this pest? I have generally hand-pulled individual plants in landscape beds growing among desirable plants. Although they have a well-developed root system, you can work your fingers in and generally get all of the roots.
In no way am I justifying this weed, but, just like many things, there is one bright side to the green shrimp plant. It is the larval food source for the beautiful Malachite butterfly. Normally found in southern Florida, its range has expanded up through and into Sarasota County. This seems connected to the caterpillar’s food source which is expanding as well. I have not seen a Malachite personally, but am on the lookout. Again, not to support a Category II weed, but at least there some side benefits.
In conclusion, the green shrimp plant is a weed worth eliminating when you can. The best we can hope for at this point is suppression to keep it in-bounds, at least within our own sphere of influence. And, it may even provide a small foothold for the Malachite butterfly as well! For more information on all types of weeds, please call our Master Gardener volunteers on the Plant Lifeline on Mondays, Wednesdays and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer. Don’t forget to visit our other County Plant Clinics in the area. Please check this link for a complete list of site locations, dates and times – http://blogs.ifas.ufl.edu/charlotteco/files/2018/03/Plant-Clinics-Schedule.pdf. Ralph E. Mitchell is the Director/Horticulture Agent for the Charlotte County Extension Service. He can be reached at 941-764-4344 or firstname.lastname@example.org.
Ruellia blechum – http://florida.plantatlas.usf.edu/Plant.aspx?id=119.
FLEPPC 2019 List of Invasive Plant Species – http://bugwoodcloud.org/CDN/fleppc/plantlists/2019/2019_Plant_List_ABSOLUTE_FINAL.pdf
Meisenburg, M. (2006) Silver Linings. University of Florida / IFAS, Center for Aquatic and Invasive Plants.
Caldwell, D. (2011) Walkable Groundcovers. University of Florida Extension Service, IFAS – Collie County.
Malachite (Siproeta stelenes) (2015) Floridata.com, Tallahassee, FL
Daniels, J. C., Schaefer, J., Huegel, C. N. & Mazzotti, F. J. (2014) Butterfly Gardening in Florida. University of Florida Extension Service, IFAS.
North American Butterfly Association Broward County Butterfly Chapter -https://www.broward.org/NaturalResources/NatureScape/CreateNaturescape/Documents/butterfly_handout.pdf