What’s with all these flowering plants? OSU experts weigh in

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A few flowers on Mexican orange are not unusual this time of year, but entire shrubs in bloom isn’t normal. Photo by Neil Bell.
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December 2, 2016

CORVALLIS, Ore. – You’d think it was spring the way blooms are breaking out all over. What’s going on?

Early bloom, even exceptionally early, is all about the weather, according to Wilbur Bluhm, a retired Oregon State University Extension Service horticulturist.

“Plants respond to weather,” he said. “If we get cold weather, they slow down. If we get warm weather, it can hasten bloom.”

An abundance of rain in October and warm temperatures in November are at the bottom of why so many plants are flowering freely now. And there’s been no freeze to stop the action.

“It usually would have hit 32 a month ago and we haven’t come close,” said Kathie Dello, associate director of OSU’s Oregon Climate Change Research Institute.

In fact, she said, the Willamette Valley is on track for the latest first frost date in history; the record was set in 1998 when it came on Dec. 9. However, a forecast of temperatures dipping into the low ‘30s next week could end the streak.

“It’s been warm,” Dello said. “We’re looking at one of the warmest years in the history of Oregon.”

So warm that impatiens, begonias and geraniums are still in bloom and many other annuals and perennials that would have given up the ghost by now are still upright. It’s not uncommon to see rhododendrons, azaleas and Mexican orange (Choisya ternata) throw off a few flowers in fall, but some are close to full bloom. Neil Bell, an Extension horticulturist, saw several Mexican orange covered in flowers Nov. 21 in Dallas.

More surprising still are the ceanothus putting on a show on the OSU campus. A spring-blooming shrub not known for repeat flowering, it threw him for a loop.

“I saw it from 50 feet away,” he said. “I thought, ‘Wait a minute, that looks really blue.’ Then I realized it was a ceanothus hedge. It was blooming like crazy.”

Mahonia ‘Charity,’ a cultivar of Oregon’s official state flower, is sending up its tall inflorescences of bright yellow blooms a month early. And another yellow flower – daffodils – are appearing in some gardens. Snowdrops must be out there sticking up their tiny white blossom, too.

Bluhm mentioned camellia as another plant doing its best to fool people into thinking it’s spring. Not only are the winter-blooming C. sasanqua in flower, but so are C. japonica, the more common shrub that usually comes into its own in March.  

The inevitable question is will these out-of-sequence plants still bloom as strongly at their regularly scheduled times? Well, that’s hard to know, Bell said, but it’s a possibility. If a plant just had a few flowers here and there, no problem. But with so many blossoms bursting from buds, it could at the very least cut down on spring bloom. And with bulbs, of course, they’ll be done. However, if you can get your hands on more (some online sources are having sales to get rid of their stock), it’s never too late to plant them unless the ground is frozen. You’ll just get delayed flowers, which will fit right in with this crazy year.

Bluhm has more than 50 years of observation under his hat as an accomplished phenologist – someone who studies how plants and animals evolve through the seasons. His seasonal scrutiny of 2,000 plants gives weight to his knowledge of what blooms when and why. He sees a lot of variability and gets questions every year about plants seeming to flower early or late. Sometimes they are, sometimes not.

“Very few people have the data to turn to, so consequently it may seem early or late,” he said. “Recall is the best they have to use to pass judgement on those situations. When I say that I’m not being critical at all. Because if I didn’t have the info I have, I might have the same idea they do.”

This year, though, they’d be right about an unusually early year. No doubt about it.

 

Author: Kym Pokorny
Source: Neil Bell