My mother-in-law just moved to Florida a few weeks ago to a 55+ community about a mile from our home. While we were waiting for her to arrive and going over to check on her place, my husband and I had the pleasure of meeting her across-the-street neighbors. Shirley and Bob hail from Rhode Island and have lived in this neighborhood for about a year. They are avid gardeners and, when looking for their place, ensured they purchased a home on the lake with a huge back yard.

My husband dropped by to see his mother the other day and Shirley was outside. They got chatting and the conversation came around to gardening and this site. Shirley posed her question and my husband assured her I could find the answer. The question was how could she remove black fungus on the rocks surrounding her garden. She had visited her local large home warehouse and they recommended bleach. Shirley, in her environmentally sound wisdom, refused to accept that as a solution and wanted something that would not harm her plants or the environment.

I have combed through my entire garden library and many online sites, and must admit I’m kind of stumped. I have found everything one would ever need to know about plant diseases and pests, but little about fungus on hard surfaces. However, I think I’ve come up with the solution. Everything I’ve been reading keeps pointing me to a mixture of 5 tablespoons each of hydrogen peroxide and baking soda mixed with one gallon of boiling water. Spray this mixture directly on the fungus and it should kill it off without harm to the surrounding plants.

Shirley, I hope this helps and if anyone reading this has a better idea, please share. I’d look forward to hearing about it.