Saving a Geranium with Blackening Stems: Winter Dormancy Care

Black stems indicate rot from overwatering and insufficient dormancy. Immediately cut off all blackened tissue. Stop watering completely. Geraniums need a cool (50–60°F), dark, dry rest. Prune to 6 inches, keep in a garage or basement (above 40°F). In spring, when new growth appears, gradually resume water and light. Move outside after nights stay above 45°F. Fertilize when fully leafed out.