Pruning fruit trees throughout San Diego County sent me “down the hill” to Carlsbad where a client had a few trees that her deceased husband had planted, trained and religiously pruned each year. One of her old peach trees in particular had been well trained, but all its new growth and fruit were beyond my client’s reach. I attempted to retrain the old peach by making severe cuts closer to the main trunk knowing that trees will produce new growth after pruning cuts or after the limb breaks. I assumed that the new growth would invigorate the aging tree. Imagine my shock and disappointment when I returned the following pruning season to see a lifeless tree whose skeleton trunk and limbs lacked any new growth at all.
Perplexed, I called my advisor at the Pomology Department at UC Davis.
“Dr. Ryugo, I made some heavy pruning cuts on a very old peach tree and no new growth emerged. What could have happened?”
He immediately replied, “Oh, we must have neglected to tell your class that peach and nectarine trees rarely have any latent buds!”
He didn’t have to explain that latent buds were growing points below the bark of older branches. They develop like all other leaf buds on new growth but do not grow into shoots until years later if damage occurs to the limb they are on. They don’t grow any sooner because plant hormones sent from growing points down the shoot, or limb, inhibit buds from growing into new shoots. A bud is considered a latent bud because it cannot grow until inhibiting plant hormones stop affecting them, which occurs after a heavy pruning cut or when a limb breaks. Uniquely, peach trees typically grow new shoots from last season’s growth on which leaf buds are clearly visible and rarely, if ever, grow new shoots from latent buds beneath the bark of older wood, a common occurrence in other species of trees.
This lack of latent buds, and the inability to grow new shoots from older wood, accounts for the often unattractive branching patterns in peach trees. For this reason, I never recommend peach trees as accent trees in the landscape. Plum trees, however, can readily be trained or retrained to have branches grow upward and outward evenly in all directions. Peach trees, on the other hand, often look poorly trained and are impossible to retrain. Since no new growth from latent buds near the base of limbs and trunk are available, retraining is not feasible. New suckers, or new growth, do not exist to be selected as future limbs to replace excessively long, broken limbs or to even encourage shoots to grow in spaces devoid of branches.
While considering that latent buds might not exist under the bark of mature peach branches, I remembered the peach tree outside the window of my boyhood home in Lemon Grove and the drastic pruning cuts made by a family friend. He assumed, like I had, that new growth would emerge from older wood. My mother and I were stunned that he left the tree lifeless. He was a great guy and we did not have the heart to complain. None of us even guessed that the peach tree did not have the capacity to regenerate limbs like other trees.
The general rule is to prune 60% of last year’s growth. Peaches need to be pruned each year leaving many shoots with leaf buds readily visible and ready to bud out the following spring season. The remaining buds will be the only points of new growth. Pruning cuts that leave no buds in view spell death to that particular limb. So avoid heavy pruning cuts on peach and nectarine trees but religiously prune back last year’s growth.
The best trained peach tree I’ve seen is grown by my friend, Usha, here in Ramona. She prunes by tipping all new growth, leaving loads of buds showing producing lush growth in the spring. She uses layers of composted horse manure and has a stream of water running near this peach during the spring. I was impressed with the profuse and balanced growth of this productive peach tree.
In the avocado groves near my home I did spot a lone peach tree which demonstrated the most growth from latent buds that I’ve witnessed on peach trees.
The above link takes you to a photo of a limb from this peach tree which surprised me by responding to a large pruning cut with vigorous growth. I suspect that lush growing conditions can override the tendency for peach and nectarine trees to suppress new growth after heavy pruning cuts.