Why are oak leaves poisonous?

You often read that you shouldn't put oak (Quercus spp.) leaves in the compost, because they'll be toxic to micro-organisms … or is that rather that they're too acid? read more

Oak leaves are not poisonous, but the leaves of a plant commonly called “poison oak” is an allergen and some people can get a bad reaction to it. Toxicodendron diversilobum - Wikipedia Toxicodendron diversilobum, poison oak, is related to poison ivy and also poison sumac. read more

Many gardeners like to use fallen oak leaves as a long-lasting mulch or rich compost ingredient. “In either role, oak leaves can become a good source of soil nutrition. But, they’re not going to decompose as fast as most tree leaves do,” Upham warned. read more

Learn about poison oak. Poison oak is similar to its close relatives poison ivy and poison sumac because they are all members of the same botanical family. The most common type of poison oak, known as western poison oak, grows most commonly along the Pacific coast in Oregon, Washington, and California. read more