A gall is an abnormal growth or swelling of a plant caused by hormones released from insects, mites, bacteria, or nematodes. They can appear on any part of the plant with vast variation in morphology, ...

Sign up for the Concord Monitor’s morning newsletter for essential news each day, and our contests and promotions list for special offers and giveaways. A student ...

It can be unnerving to find that the leaves of an oak or hackberry tree are as bumpy as a rock-covered seashore in late summer. Other trees’ leaves may break out in acne-like red spots or sport ...

Dear Neil: What are the pimple-like growths on the leaves of my hackberry tree? Are they harmful? Those are insect galls that result when the female insect stings the leaves of the tree and lays her ...

Each year in late spring and early summer, homeowners begin noticing strange growths on the leaves or stems and are concerned for the health of their trees. Several different types of galls are common ...

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 ...

A student plopped a leaf on my desk, pointed to several green lumps on its underside, and asked, “What are those green growths?” It was a stump-the-professor moment and in this case, I was, indeed, ...