Roy Robison isn’t likely to soon forget May 1 and May 3, 2010, when 800 acres of his 1,710 acres of producing pecan trees were clobbered by frost.

The rest of the trees escaped with little, if any, damage. At one point, the thermometer dipped to 23 degrees, and stayed there before rising.

The frosted trees included 200 acres planted two years ago, says Robison, manager of Chase Farms pecan orchards near Wilcox, Ariz.

A spring frost isn’t all that unusual for the high-desert southeast Arizona ranch, where Robison was born. “Our elevation of around 4,100 feet is a little high for pecans,” he says. “Usually, if we can get past April, they do really well. We’ve had hard freezes over the years, but this one was about as bad as I’ve ever seen.

“The frosted trees were damaged from top to bottom — they looked awful for about two months. You can still see the fried catkins and pistillate flowers.”

Since the freeze, Robison’s ongoing hedging program, along with a normal flood irrigation schedule and intensive fertilizer management, have helped the trees rebound. “We’ll even harvest a few nuts from them this year,” he says. “Whether they’ll be any good remains to be seen.”

He’s pleased, though, with the appearance of the undamaged trees. “They have a very good crop on them,” Robison says. “Nuts are sizing well and expanding. We had a good nut set and a very minimal drop in June. Usually, we get a heavier drop during the second or third week of August.”

The farm’s bearing trees, planted by Robison’s father between 1979 and 1984, are Western Schley, except for 40 acres of Wichita pollinators. Two years ago, Robison began expanding, with annual plantings of Pawnee, with Bradley as the pollinator in every 10th row. The young orchards total about 400 acres and he plans to add more trees over the next few years.

Chase Farms’ goal in planting the Pawnees, which can mature as much as a month or so ahead of Western Schley, is to capture the typically higher early-season pecan prices.

Unlike older orchards planted on a 30 x 30-foot spacing, the new trees are spaced 30 feet between rows and 15 feet down the tree rows. The denser plantings obviously produce more nuts per acre.

“We’ll try to keep the trees to a height of 20 to 22 feet and no more than 6 feet or 7 feet wide by hedging them crosswise, doing every other row every other year to keep tree growth in check,” Robison says

He credits his hedging program in the mature orchards, started 7 years ago, with helping to speed recovery of the freeze-damaged older trees this year. “Those trees shot out 3 feet to 4 feet of growth this season,” he says.

In addition to invigorating the trees and building fruiting wood on the inside of the limbs, hedging helps keep them more manageable and makes shaking easier. “Before we began cutting them back, we had trees in excess of 40 feet tall and 20 feet wide.’

The hedging wood is windrowed and shredded in the orchard. It takes about a year for it to break down.

A sound fertilization program has kept trees healthy and able to recover from the spring freeze, Robison notes. Starting when night-time temperatures remain above 40 degrees, usually in late April, he feeds the trees six times a season, using a power sprayer to apply liquid nutrients to the leaves.

The sprayer is calibrated to provide 3 pounds of zinc sulfate and ½ gallon of UAN 32 in 100 gallons of water per acre. Each application requires about five nights to treat all the trees. This season, the first spray began April 25 and the sixth application was finished July 20.

Robison spreads gypsum at the rate of 2.5 tons per acre before watering it in with his first irrigation of the year. Prior to his second irrigation in May, and each one after that, he broadcasts 36 percent urea granules on the ground, which provides about 65 units per acre per irrigation. The orchards get 200 to 240 total units of N per year.

Robison has drilled new wells to provide the trees water on a more timely basis, and has reduced the time he can complete an irrigation cycle by at least a third — from 45 days to 28-30 days.

The cost of lost production from this year’s freeze may not be as much as first feared, if the pecan market can maintain its current strength, Robison says. “Because this is an off-year in most of the U.S., this should be a good year for pecan prices; right now, I hear talk of $3 per point.”