Why are black currants legal to grow in some states/counties and not in others, and what is the status in Virginia?
This information is specific to Virginia and may or may not be applicable tdo your area.
Growing black currants is still outlawed in Virginia. Virginia Department of Agriculture officials state that true black currant (Ribes nigra) is still regulated and illegal to buy, possess, grow, or sell in all counties in Virginia.
The prohibition stems from national forestry preservation laws related to prevention of white pine blister rust in this country. Ribes species serve as alternate hosts for the disease and can infect the important timber pines with this devastating disease. All Ribes species (gooseberries, white and red currant, etc.) were once outlawed in many states (particularly in the northeast), but the laws have been relaxed, ignored, or reversed, resulting in many variable and confusingly enforced regulations. It is especially problematic for nursery owners who must abide by this tangle of current interstate shipping laws.
According to the Virginia Department of Agriculture, a change in the existing law is possible but will require new legislation and industry leadership to push for change. Until that happens, they are leaving open the interpretation to allow all Ribes, crosses and otherwise, except the true black currant,which will continue to be prohibited.