What to do with runted trees?
A Pennsylvania pomologist recommends drastic measures.
What do you do with a block of young Gala trees that have stopped growing before their canopies have filled their spaces? International Fruit Tree Association members pondered the question during a visit to an orchard owned by Adams County Nursery in Aspers, Pennsylvania, earlier this year.
Chris Baugher, the nursery’s vice president of operations, showed the group a fourth-leaf block of Gale Gala apples on Budagovsky 9 rootstocks that had been planted on a 4- by 16-foot spacing.
Dr. Jim Schupp, pomologist at Pennsylvania State University, said B.9 is a low-vigor rootstock. The block site was a former stone fruit orchard.
Precocious varieties, such as Gala, will flower immediately, Schupp said, and on light soils they can runt out after they start to fruit.
“If we just try to do a little pruning and a little fertilizing, they will stay runted. We need to take drastic action. Unless these trees fill the space, this will never be a profitable block. It doesn’t matter how pretty the apples are, there’s not going to be enough yield to recover the initial investment unless they fill their space.”
The drastic measure Schupp had in mind was mounding soil around the trees so they become scion rooted, overcoming the effect of the dwarfing rootstock. In five or six years, if the trees become excessively vigorous, there are tools to address that, he said. “We do not have tools for dealing with low vigor.”
Other growers suggested less drastic measures, like cropping the trees lightly and fertilizing heavily, and then pulling the trees if all else fails.
But Schupp insisted it is not a problem that can be cured with a bag of fertilizer.
The block might be removed in a few years, but in the meantime, scion rooting would improve yields. After making a considerable investment to establish the orchard, it’s hard to walk away from it, he said, and other, older blocks with big trees are in greater need of renovation.
The block has good potential, if it were not for the lack of vigor, he said. “The variety’s right, the spacing’s right. All you have to do is get it going. If it was an unprofitable strain or variety, then I think at that point you cut bait and get out and start again right. In this case, everything’s right except the trees are not growing.”
In a 12-year-old block of Gala, Baugher demonstrated his pruning strategy, which is designed to be simple so that pruners don’t have to make too many decisions as they work.
There are several rules:
—First, take out the two biggest branches, making sure there’s still a central leader.
—Where a limb divides into two, cut it back to one.
—Cut back pendant wood by half.
The only problem with this is that it doesn’t help thin the crop, so Baugher added a new rule this year, which is clean out the spurry growth. However, getting down to the detail pruning is always difficult, particularly with pruners paid piece rate, he said. He pays 30 to 35 cents per tree and there are 430 trees per acre.