I have a question regarding a yellow foam that has been shown on two occations in my backyard. First time it was on the lava stones. We thought it was one of our babies that had been throwing up, as it was quite a lot. It looked like cheese doodles. Second time is was again on the stones but also on one branch of a plant. It was dry yellowish foam. What could it be?
Yellow Foam on Stones and Plants
Certified GKH Gardening Expert
You have a slime mold, which some people also call dog vomit fungus. It is not dangerous and normally goes away on its own. This is oftentimes seen in areas with lots of mulch. The best way to avoid these is to make sure your mulch is not too thick, to use mulches that are not too fresh and already partly composted. This article will provide additional information: https://www.gardeningknowhow.com/ornamental/fungus-lichen/what-is-slime-mold-slime.htm