From the NC Department of Agriculture website: “Currant and gooseberry plants (the genus Ribes) cannot be legally imported into, or grown in, North Carolina because they serve as alternate hosts to the plant disease known as white pine blister rust. This is an old regulation established when young white pine plantations were threatened by this disease because of infected, wild currants growing in close proximity to them. There still is an active eradication program in the western area of North Carolina to eliminate wild currant hosts within a certain distance of white pine plantations.”

 

The regulation banning Ribes in NC can be found here: http://www.ncagr.gov/plantindustry/Regs/48a0400.htm