The sign pictured identifies our native Blue Porterweed, Stachytarpheta jamaicensis. One of the first chores completed in the garden was the removal of all the non-native Porterweed, Stachytarpheta cayennensis (synonym S. urticifolia). Not only is this plant not a native, it is also listed on the Florida Exotic Pest Plant Council's 2005 list as a Category II plant. These are species that have shown a potential to disrupt native plant communities. Part of the plan for the garden is to have it free of all plants listed as exotics by the FEPPC.
Native Porterweed is a low growing, spreading plant that rarely exceeds 2 feet in height, and may reach 3 feet or more across. The plant is moderately salt tolerant, prefers full sun but tolerates partial shade. Its native range is South Florida; probably native only to Monroe, Dade, Collier and Lee County, but it grows well in this area. The plant is easily propagated by cuttings.
The light purple-blue flowers provide nectar for a host of butterflies. It is also a larval food for the Tropical Buckeye, but this butterfly, like the plant, does not occur in nature this far north.
References:
Florida Exotic Pest Plant Council's 2005 List of Invasive Species: http://www.fleppc.org/list/list05web.pdf
Natives For Your Neighborhood Blue porterweed, Joee: http://regionalconservation.org/beta/nfyn/PD_PFriendly.asp?tx=Stacjama
Butterflies and Moths of North America Tropical Buckeye: http://www.butterfliesandmoths.org/species?l=1778&chosen_state=12*Florida