Plants break dormancy early | Cold snap needed to get plants blooming
FORT SASKATCHEWAN, Alta. — Patricia Turanich thinks something crazy is going on with her fruit trees.
Little brown buds have pushed out of the branches and shoots are poking out of the ground. A tiny pink bloom has pushed out the tip of her rose bush.
“I’m not doing anything. It’s doing it on its own,” said Turanich, whose yard sits on top of the North Saskatchewan River Valley on the outskirts of Fort Saskatchewan.
It’s the same with Turanich’s gooseberry, chokecherry, black current, raspberry and rose bushes.
She first noticed the brown buds and green leaves on some of her trees right after a cold spell in December and again after another cold spell in January.
“I keep trying to tell people something is happening,” said Turanich. “Something happened right after - 48 C weather.”
Retired Alberta Agriculture scientist Ieuan Evans hasn’t seen Turanich’s plants but he said early budding can be attributed to the warm weather.
“We’ve had a mild October and November. Those plants think spring is here. They’ve had enough cold weather and are now starting to bud,” said Evans.
Like most plants, fruit trees and roses need a period of vernalization, or cooling, to break dormancy before flowering.
Fruit trees need only roughly 60 days of cold weather before they can begin to flower again. Other trees such as poplar and spruce need 120 to 160 days of cold weather before starting to flower.
Plants in a low spot in a yard or field are even more susceptible to early budding.
Temperatures fall at night rise during the day, convincing trees that they’ve had enough cold weather.
It’s not unusual for plants to bud weeks or months early if they’re in a microclimate that tricks the plants to believe winter has passed, he said.
As an adviser with Agri-Trend, Evans has also had reports of winter wheat crops in Manitoba and Saskatchewan that started to turn green in December.
Temperatures in fields on a south facing slope on a sunny day can easily reach 10 or 15 C.
Evans said the warm weather would mean his normally cold garage isn’t cold enough to put the lilies and daffodils through their vernalization period. Before spring, he will need to move them to a fridge to trick them into blooming in the spring.
Dean Kreutzer of Over the Hill Orchards north of Regina posted a tweet that the warm weather has started to confuse his trees.
The plums, pears and apricots inside his normally cool Quonset are all pushing buds and some are blooming.
“They’re two months ahead of where they should be,” said Kreutzer, who was pruning grape vines inside the Quonset. The Quonset temperature is normally -2 C to -5 C, but it’s been 7 C to 10 C so far this year.
“Normally they don’t start sprouting in the Quonset until the end of March, and I have plants in full bloom.”
Luckily, none of the trees in the outside orchard are showing any side of budding, he said.
“I’m looking at the apples and they’re holding tight. That’s really good. If they started to bud out and bloom in March or April, we would be in serious trouble.”