Last year, I had an arborist out to visit to help understand what on Earth falls out of the mongo oak trees over the driveway.
Every Spring and Summer for several years, the trees produce a never ending rain of.. crap. Sappy droplets that don’t wash off your windshield, and later, a steady rain of sand-like plant material. Enough to cover the driveway every day. Pics from last year: https://photos.app.goo.gl/FrZFaUN2HmUtkc2w5 .
My research led my to some version of a gall wasp infesting the trees. What gall they have!
The arborist confirmed that these bugs are the cause, and there’s really not much you can do about it. Some years are really bad, some years they are less of a problem. So far 2024 has not been too bad, fortunately! And despite the damage on these leaves, the trees are so big that there’s nothing to worry about, health wise on the trees. Another case of “what good are wasps”..
