Urban Orchards : How Limbs Prune Themselves

How Limbs Prune Themselves

If you study an apple tree that has been spared from the clippers, you will notice two characteristics of the branches. Some will reach toward the sky, straight and lean. Other branches weep low to the ground and are laden with small fruit. Vertical sprouts eventually bend down under their own weight and that of whatever fruit happens to form. Then an exciting thing happens: just past the peak of the arch, many dormant buds turn into flower buds or short laterals with flower buds on the end. In section “A” (see figure 4.14) more fruit spurs than branches form. And because the terminal bud loses influence in a downward position, the branch tips rate of growth is greatly reduced.

Once fruit spurs form, the increasing weight of each season’s crop soon bends the branch below horizontal, forming a weeping branch. Yields increase each year because more food from the leaves is stored in the spurs. In section “A,” where more buds become fruit spurs, no new branches are formed to compete.

At the top of the arch, the buds grow into vigorous vertical limbs. The first bud to sprout quickly gains dominance over the others. It shoots upward more rapidly, getting long and leggy. With time it, too, arches down and becomes fruitful.

In a season, weeping branches grow only a few inches, while vertical shoots may gain more than two feet. In effect, the tree prunes itself to be more fruitful. It’s shape, however, is considered unusual by some gardeners.

Reprinted with permission from:
Designing and Maintaining Your Edible Landscape Naturally, by Robert Kourik. Metamorphic Press, 1986. To order write to Box 1841, Santa Rosa CA, 95402. OR call (707) 814-2606. $50 + $5 shipping.