Trees offer advantages for efficient harvests
By JOHN SCHMITZ
For the Capital Press
AURORA, Ore. -- As odd as it seems, blueberries do grow on trees. But the wild fruit has little if any commercial value.
Oregon State University berry crops extension agent Wei Yang, who works at the university's North Willamette Research and Extension Center near Aurora, is out to change all that.
Financed with money from the Oregon Blueberry Commission and USDA's Specialty Crops Research Initiative, Yang grafted four commercial highbush blueberry varieties -- Duke, Draper, Liberty and Aurora -- onto wild blueberry tree rootstocks that originated in Texas, Oklahoma and Florida.
"With the bush form, during harvest you have lots of berries falling to the ground," Yang said. "With the tree type, you have fewer berries falling to the ground because the catch plate from the mechanical harvester will be able to close very tightly around the trunk."
It's somewhat similar to machine harvesting cherries, Yang said.
He added that blueberry trees have been known to yield up to 30 pounds of fruit per tree, compared to 15 pounds when grown on a bush.
While overall yields may not increase that much due to the wider spacing that blueberry trees will need, growing blueberries on trees could very well offer several advantages over bushes, Yang said.
Better drought tolerance is a goal. Others include higher resistance to certain diseases and the elimination of the need for sawdust. Yet another feature could be increased cold tolerance.
Yang, who is in the second year of a five-year project, has been both budding and whip grafting blueberry scion wood in the greenhouse onto the wild rootstock. Next year there should be a "large block" of trees at the research station, he said.
While some people have tinkered with growing popular blueberry varieties on grafted, wild rootstock, this is the first time that a major study has focused on doing it on a commercial scale, Yang said.
"The goal of the project is to demonstrate in a commercial planting if blueberry trees will work," he said. "I can give you a blueberry tree right now and it will grow in your back yard. We want to know if the trees will grow (the desired cultivars) on a large scale."
Yang said blueberry trees, which should start bearing fruit about the same time as bushes, can reach heights of up to 14 feet, "but you may not want them that large for commercial production."
He added that while he plans on giving the tree-borne blueberry project a lot of attention, growers should not get their hopes "too sky high."
Yang said that soon his evaluations will begin in commercial fields and that by 2014 he'll have a good idea if the concept works.