Ask the master gardeners
Q: I was told not to grow currants in my Lower Hudson Valley home garden. I was told they will affect trees in the area. Please explain.
A: Red, white, and black currants are members of the plant genus Ribes, which also includes gooseberries and many ornamental plants. Ribes are host plants of a fungus that devastates white pine trees — white pine blister rust (Cronartium ribicola).
The fungus does not spread directly from pine to pine, but spends part of its life cycle on a member of the Ribes family. Black currants (Ribes nigrum) and white pines (Pinus strobus) are very susceptible to the rust, while red currants and gooseberries are somewhat susceptible.
White pine blister rust is lethal to white pines if it spreads from an infected branch into the tree’s trunk. White pine blister rust was brought to North America from Germany on seedlings of Pinus strobes (Eastern white pine) around 1898. In 1911, federal regulators and states tried to control the spread of the fungus by prohibiting the cultivation of currants and gooseberries across the country.
In 1966, the federal government lifted its ban, but many states kept similar laws on their books.
By the 2000s, scientists had developed a more nuanced picture of white pine blister rust’s life cycle. It had become clear that the disease occurred primarily in moist areas where currants grew near pines, and that it affected mostly young seedling pines.
In 2003, New York state modified its ban to allow commercial growers and home gardeners to grow red currants, gooseberries as well as immune or resistant cultivars of black currants. Some states such as Maine, South Carolina, North Carolina, Virginia, New Jersey, New Hampshire and Massachusetts still uphold a ban to varying degrees.
Currants and gooseberries are wonderful garden plants that produce delicious, healthy fruits. Plants will fruit even in partial shade.
Cornell Cooperative Extension recommends black currant cultivars ‘Consort’, ‘Crusader’ and ‘Titania,’ hybrids that are resistant to the blister rust fungus. For more information, visit www.fruit.cornell.edu/mfruit/gooseberries.html and www.fruit.cornell.edu/Berries/specfrhtml/ribescult2003.html.
— Beth Hanson, Tarrytown, master gardener, Cornell Cooperative Extension of Westchester