Warm weather could cause some plants to bloom early, which could be harmful when cold weather returns

The Record‘s James M. O’Neil provides this humbug report:

So you’re indulging in this freaky-warm un-February, eh?

Celebrating your snow-free driveway. Cheering that iceless windshield. Basking in false spring temperatures reaching into the 50s, 60s and even – possibly Friday – the 70s.

But even with great winter weather, there’s no free lunch.

This February, which could end up one of the three warmest on record in New Jersey, is coaxing tree and shrub buds to start swelling early. That should continue as forecasters predict warmer than normal temperatures for at least two more weeks.

But if we get blasted with a cold snap and frosty nights, those buds could be killed off.

WARMING: Temperature could hit 70 degrees
MILD TEMPS: Why has it been so weirdly warm this winter?

And suddenly, poof – there go the state’s colorful spring landscapes of blooming magnolias, cherry trees and ornamental pear trees, reduced to burnt brown petals hanging limply from their branches.

It happened last spring to saucer magnolias, which were in full pink flower when the temperature dropped one night to 20 degrees. “The petals were hanging all brown into late May,” said Bruce Crawford, director of the 200-acre Rutgers Gardens in New Brunswick. “It was really unappealing. But there’s really nothing you can do about it.”

Kevin Eisele of Eisele’s Nursery and Garden Center in Paramus agreed. “We just have to hope it cools down again soon,” he said, which could suppress buds from continuing to swell. “Otherwise certain species of plants probably will get hurt.”

Any early-spring flowering trees could be affected, said Bill Zipse, regional forester for the state Forest Service. “We’ll have to keep watch over the next few weeks for potential frost damage,” he said.

Native dogwoods, whose striking four-petal pink or white flowers are really modified leaves called bracts, often lose the outer two bracts if a frost hits while the trees are still budding, reducing their aesthetic impact.

Another highly susceptible landscape plant is the non-native hydrangea. Because they grow buds on old wood from the prior year, they can start early, but if they start drawing water up into the stems and cold weather sets in, the water freezes, stem cells burst, and the plant won’t produce its distinctive blue and pink pom-pom flowers that summer.

“They really take it on the chin,” Crawford said.

Buds on other trees have also started to swell, such as silver maple and red maple. Mike Limatola, marsh warden at Celery Farm in Allendale, said he saw buds swelling on maple trees there over the weekend.

While trees can’t grow new flower buds if killed off, they can grow new leaf buds, Zipse said. But repeated seasons with early growth followed by cold weather and lost buds can stress some trees, experts say.