I may have hurt our wisteria. It has been growing on a pergola for quite a few years now. This year, there are very few blooms and the whole tree has very few leaves as well, with many of them looking dried up. Last fall I cut down a spruce tree in the yard and piled the branches under the pergola with intentions to burn the branches in a nearby fire pit soon. Unfortunately, the branches sat under the pergola (next to and under the wisteria) until today, when I finally removed them. In addition to that, as I was removing the branches, I found a strange white foamy substance in the pile all the way down to the ground covering about a 4′ diameter. The foam didn’t appear to be insect larvae but more like some kind of fungus perhaps. Do you think the ground has become acidic due to the spruce tree branches being there and do you think there is concern about the foamy substance?
I would suggest having a soil test done on the area you are concerned with.
Your local County Extension Office can help with this.
Here is a link to locate your closest office.