<b>Battling the Down Economy:</b> Plant growth regulators could reduce need for manual pruning.

Manual or mechanical pruning and shearing of nursery crops are necessary evils.

Regular pruning of most woody ornamentals increases branching and fullness, and creates the compact shape that customers demand. But the labor needed to shear these crops, then dispose of the clippings, is costly.

If there were only a magic potion that would make pruning unnecessary.

Developers of plant growth regulators, or PRGs, are working on it. These products have long been used on herbaceous crops such as annuals and perennials. Now new products and new tests are being done to achieve the same effect on woody ornamentals.

Jeff Stoven, head grower at Bailey Nurseries’ Yamhill, Ore., facility, has done much experimentation with PGRs on both trees and shrubs. The company has successfully used them on perennials in the past, and now is focusing on how woodies respond to PGRs.

“With woodies, there’s not much research. It’s uncharted territory,” he said. “I have to make sure that it’s in my comfort level before we use anything on a broad scale. I’m pretty conservative and like to try things for two, three or four years before I like using it on a broad application.”

But his company is regularly treating Endless Summer hydrangeas with PGRs. During spring forcing, container-grown plants are treated with a tank mix of B-Nine and Florel once the second set of true leaves emerge. This helps control height and produce fuller plants.

Bailey Nurseries is also tinkering with Florel on other deciduous woody crops (weigelia, syringa, spiraea and others) but have come to no set conclusions.

A new product, Augeo, is showing promise for increasing lateral branching on amelanchier, birch and perennials.
“We’re getting our feet wet with Augeo,” Stoven said. “It’s showing a lot of merit, but we haven’t come to any hard conclusions.”

But with the vast amount of labor expenses these products could reduce, Bailey Nurseries is going to keep experimenting.


For more: Bailey Nurseries, (503) 662-3244; www.baileynurseries.com.

New PGR products and new tests are being done on woody ornamentals.