GRAND RAPIDS (WZZM) - West Michigan gardens recovering from the drought are now encountering another problem: Downy mildew. It's a parasite that affects impatiens, which make up a third of all bedded flowers in our state.
The spore causes impatiens' leaves to turn spotted and yellow, and eventually fall off. Infected plants left in the garden can infect the soil, leading to a long-term problem.
"It produces a specialized spore that can last for five to seven years in the garden and cause problems with impatiens if you go in and plant impatiens after a downy mildew outbreak," says Thomas Dudek, Senior Extension Educator, MSU Extension. "If your plants are infected, you're going to have to dig them up and remove them and consider planting something else next year."
Gardening experts say hotter temperatures actually deter downy mildew, which spreads by spores carried by wind and rain splash. Michigan greenhouses use fungicide to prevent the problem but those chemicals are not available in stores.
You should always check the underside of impatiens' leaves for any fuzzy gray mold, and only buy healthy green plants.