Sioux City Journal, IA
04-16-07
Too early to determine possible crop damage
By Russ Oechslin, Journal Correspondent
SUPERIOR, Iowa -- Area nursery pros agree it's too early to determine the extent
of damage to budding trees and plants after a week of snow and temperatures
well below the freezing mark followed a spring heat wave.
Dave Mosher of Mosher's Greenhouse and Landscaping in Sioux City explains
that "most deciduous trees -- unless sap got caught in the trunk, then froze and
cracked the trunk -- will survive with distorted foliage this summer," if they were
budded out.
Some gardeners, Mosher admits, "got hurt bad. Foliage in bloom was most
affected -- some daffodils, tulips and the like -- by 14-degree weather and plants
being as far out of the ground as they were."
But plants not quite in flower may still have some flower production, he adds.
Del Brockshus of Del's Garden Center in Spencer, echoes Mosher's thoughts,
adding that further south, where temperatures were much warmer the week
before the snow and freezing temperatures, buds had made more progress.
Harlan, in Shelby County just north of Interstate 80, Brockshus explained, is
about two weeks ahead of Spencer in its growing season.
Don Obrecht, who planted about 135 grapevines on one-quarter acre he had
available three years ago, says he's "unfortunately trying to raise grapes," and he
said he is concerned about his young vines, for which there is no crop the first
two years.
His plants were at the start of the bud swell stage when the cold-snap hit, and
may be damaged. But Obrecht said he expects the secondary and tertiary buds
may survive.
"The first years' crop isn't generally great anyway," he says.
In northernmost Dickinson County, Scott Benjamin of the Little Swan Lake
Winery has been raising grapes for about eight years. He admits losing about 20
percent of his 1,000 vines in that time because he selected varieties that were
not suitable for the Minnesota border climate. Still, says Benjamin, it's too early to
tell how the 2007 crop might be affected.
Paul Domoto, a horticulture professor and Extension fruit specialist for
Iowa State University, says "As would be expected, damage is more severe in
warmer regions where buds were more advanced."
At ISU's grape research plot near Lewis, Iowa (east of Council Bluffs), Domoto
reports he saw "extensive primary bud injury on several cultivars that were in the
final swell state of development."
But near Ames, "The buds were in the first swell stage and there is some injury
that we need to fully assess. "With grapes, there are multiple buds, so there is
still a good chance of a crop," he adds. "In apples, south and southwest Iowa
trees were in the half-green to tight cluster stage of development while most
central Iowa trees were in the green tip to half-inch green stage. We are seeing
injury in the buds but can still find some live buds in the floral cluster. So there is
still hope for the crop.
It is still early
While many people are anxious to get into their gardens -- and many did two
weeks ago before the snow -- Mosher and Brockshus say it's about a month too
early to plant vegetable gardens.
"We've had two years of warm Aprils and cool Mays. I'm hoping May will be
warmer this year," Mosher explains. "I tell everyone not to plant vegetable
gardens until after Mother's Day. The nurseryman added he can even remember
a hard freeze on Memorial Day when he was eight years old.
Similarly, Brockshus notes that on average the last frost in Spencer is May 10.
But, he warns, "last year there were eight nights of frost after May 10."