Sometimes, it can so happen, those certain kinds of abnormal plant growths start to develop on trees. Such growths can be found on the leaves, twigs, and branches of a tree and we call them plant galls.  Now, plant galls do not look like any kind of normal growth at all. For example, some galls just develop as small bumps on the leaves of a tree – and that just looks wrong. But, some other galls might develop as outrageous tumorous growths instead.

Different species, sizes, and colors of plant galls

You see, there are actually many, many different types of plant galls and not just one. And, depending upon the species, galls can be anything from small and simple lumps to much bigger and more complicated protruding structures of some sort.

The same thing goes for the color of the galls – depending upon the species of the gall; its color can be anything between a dull brown and vibrant green.

What causes plant galls to develop on trees?

Just like how “what a plant gall looks like” varies from species to species, so do their causes. The most common cause of plant galls is usually insects. Now, how to insects cause plant galls?

Insect activity on tree leaves

Insects share a special relationship with trees (and plants of all kinds). Many insects feed on the leaves of the trees. And, many others even lay their eggs on these leaves. Such kinds of insect activity on tree leaves can stimulate the growth of plant galls. These plant galls, then, help house the newly laid insect eggs and/or the hatched larvae. The plant tissues help to shelter and protect not only the eggs but, in some cases, the insects themselves. In other cases, the plant tissue might also feed these insects as well.

Other causes of plant galls

Insects are not the only cause of plant galls, however. For example – even certain bacteria, viruses and fungi can cause galls to develop on a tree.

Are galls a problem?

Short answer – probably not. Most galls are not a problem at all. They might not look good, but they are okay otherwise as far as the wellbeing of the tree is considered. However, some particular galls can be nasty. Such galls might need to be treated immediately if you want to save the tree.

For further diagnosis, the best advice will come from a local profession at a tree service company.