“What is causing these lumps (above) on my live oaks?” asks Birds & Blooms reader Katherine Gerritsen of Grand Cane, Louisiana. Horticultural expert Melinda Myers says, “Abnormal growths on a variety ...

What are these blister-like things on the leaves of my oak tree? Will it harm them? P.T., Tulsa The structure on your leaves is a common oak leaf gall and will not harm a mature tree. Galls are ...