Understanding a Little About How Plants Grow

The way plants become taller and broader, lengthening and extending their branches, is by the growth that takes place from buds located at the tips of the shoots. After that growth is completed, the new portion hardens and remains in the same position permanently. It does not move farther up or outward. Only new growth at the tips continues to extend

The circumference of branches and trunks increases each year, because a new layer of growth is added on the outside. The center part of the branch or trunk does not grow. On a tree, rose bush or woody shrub, you can scratch away some of the outer bark and find below it a green layer. This is the cambium, the precious part in which growth takes place. When a tree is cut down, you can see in its cross section the series of rings recording the amount of yearly growth,

The location of a branch on a tree or shrub is permanent. However, each year as the tree grows higher, the stem or trunk, and the branches become bigger around. You must look ahead and visualize how large those main branches may become, and provide space for them to develop without crowding.

Growth buds are the key to pruning. They are undeveloped branches. You will notice them on each stem or twig. In winter, on plants that shed their leaves, these buds are easy to see. During summer, or all year on plants with evergreen foliage, the buds will be inconspicuous in the axils of the leaves (the spot where the leaf stem joins the main stem). Each leaf indicates or marks the location of a growth bud. In some plants the buds are always arranged opposite one another along the stem--an example is lilac. In others they are always alternate, or somewhat spirally arranges--an example is spirea. These facts will play a part in the way you prune.

Tip or terminal buds are the most important ones. They are at the top or end of each stem, and are larger than the lateral buds. They are the kings, the leaders, doing the most growing, extending the length of the branch in the direction that it is pointing. On branches with buds arranged opposite to one another, there will be a pair of terminal buds, and they will both be leaders and develop equally unless something happens to one of them.

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