I believe beautiful tress encircling my deck are causing a huge maintenance challenge

Asked July 9, 2018, 10:32 AM EDT

I face a serious challenge cleaning my deck, and some of the literature I have read indicates that trees can produce some by-product that can settle on decks and produce unsightly splotches. I have had this problem for years, it is worse this year. Products with bleach seem to work best, but those products can damage other plants as well as my lawn. My strong suspicion that this is some type of airborne problem is supported in part by the pictures I have attached. There are no splotches under my grill, or even close too the grill which has a cover. There are few if any splotches or spots under the deck furniture. But in the middle of the deck, the spots are everywhere, and pretty unsightly. I am pretty familiar with deck cleaning products, and the best performing products have some bleach in them, but I think the bleach can be pretty destructive. I found an article in the Washington Post that recommends Copper Sulfate Powder for problems related to airborne particles, including particles from trees, but this product does not seem to work very well either. I am hoping that you could educate me as to what type of airborne particles from trees might be contributing to, or causing this problem. I can appreciate you may be very reluctant to suggest any specific product that might help me, but if you could give me some general guidance as to the type of solution I should pursue I would be very, very grateful. There are just so many hours this 72 year old can spend cleaning a deck, especially since most of the products suggest that full sun in the heart of the day is best for deck cleaning !!! Thanks for any information you can provide..

Howard County Maryland honeydew miscellaneous trees

2 Responses

This substance on your deck is probably honeydew from the trees above. Honeydew is a substance produced by insects feeding on tree sap. If you have tulip trees in the vicinity of your deck, this is one type of tree, in particular, that is attractive to aphids and scale insects that produce copious amount of honeydew when they are feeding. https://extension.umd.edu/hgic/aphids-trees-and-shrubs
There is no specific product we can recommend for deck washing. You might try just plain soapy water to see if that will take care of it if you are concerned about the use of bleach. Another option would be power-washing.


Thank you so much for your response. My back yard backs up to a Howard County preservation area, and at the perimeter of my yard there are a number of very mature trees, including two very tall trees with (to me) unusual leaves. I think these might be tulip trees....these are shedding some leaves right now, as these trees don't seem to enjoy the heat. They are tall enough and close enough that some of these leaves are falling on the deck. Aside from these neighboring trees, I have trees all around and near the deck.....maples, one pine tree, some hollies, a couple of cherry trees, and a very old black cherry tree that the builder left near the back of my yard. I will miss all of this when I move.....but I won't miss cleaning the deck. I have already power washed, used a product that has bleach in it, and right now am trying a solution of warm water and copper sulfate crystals. Only the copper sulfate seems to be working....but not too well. That is why I sought some expert help as to what is causing this problem . My thinking is that the tulip trees are the source of the problem, but maybe all the trees are contributing in some way.. I will search for a stronger bleach product. I am very grateful for your help. You're knowledge and analytic skills are amazing. I am very grateful for your help, as well as your patience .