Our flowering currant has rust disease. It flowers beautifully but looks hideous for most of the summer and fall until its leaves drop. We’re debating whether to remove it, though we love the reddish blooms. Is it affecting other plants in neighboring gardens (for instance, our neighbor’s Heuchera which has rust)? Are there varieties of currant that are rust-resistant?
Your currant (Ribes sanguineum) is probably infected with white pine blister rust (Cronartium ribicola), which also affects some edible currants. As the name of the fungal infection suggests, this is a disease that passes back and forth between its hosts–currants (which aren’t killed by it) and white pine or Pinus strobus (which is seriously harmed by it). Don’t feel guilty about the neighbor’s Heuchera rust, which is caused by a different fungus specific to that plant, Puccinia heucherae. However, if there are white pines within 1,000 feet, the disease could kill them.
The link above mentions that Ribes sanguineum is very susceptible to the disease. Several varieties of edible red currant are rated as virtually immune (‘Viking’ and ‘Red Dutch’), but these are not the type of currant grown for their highly ornamental flowers. I could not find any information about resistant flowering currants, but if there are pines in your neighborhood which have the fungal infection, the rust may continue to be a concern for any future currants you plant.