zinnea leaves have brown spots,

Asked July 18, 2016, 12:11 PM EDT

Tall zinnia plants have large brown spots. Should I remove them ?

Stearns County Minnesota brown spots on leaves horticulture zinnias

1 Response

Your plants may have bacterial leaf spot. The following is from our "What's wrong with my plant?" diagnostic tool. There is a link to a very good publication here as well. http://www.extension.umn.edu/garden/diagnose/plant/annualperennial/zinnia/leavesblotchesorspots.html

The leaf spot disease can be managed by buying disease-free plants, by spacing plants to increase air circulation, and by avoiding overhead watering which can splash soil-borne pathogens on to leaves. You don't need to pull out the plants, unless they become really damaged.; however, you should remove the plants at the end of the summer and burn or compost them (the bacteria does not survive winter).