Touch of Spring in December on East Coast as Flowers Bloom Early

'Ah, the pleasures of the New York Botanical Garden in winter. The crowds thronging to the Holiday Train Show. The deep greens of the hardy conifers.

And, this year, the sweet aroma of flowering viburnum.

Across the region, this uncharacteristically warm winter has flower beds springing to life. Daffodil bulbs in suburban gardens are sending up tender green periscopes. And in city parks, roses are showing their plumage against Christmas tree backdrops.

It is not normal. And while the plants will probably not be harmed in the long run, it may mean a less vivid floral parade in the spring.

“When you smell something that smells like spring now, that’s a little bit unexpected,” said Brian Sullivan, the botanical garden’s vice president for gardens, landscape and outdoor collections. “It’s unusual to smell the fragrance of a viburnum in December.”

Mr. Sullivan said the out-of-season blossoms fit into two categories: fall flowers that are having an extended blooming period, and spring flowers that are opening up too early.

Asters, toad lilies, chrysanthemums and certain anemones are examples of flowers that usually bloom in the late summer and fall but are also appearing in gardens this winter.

“They would have been cut short by a series of cold nights that we would have had in November, but that never happened,” Mr. Sullivan said. “It’s very odd.”

In addition to viburnums, some of the spring woody plants that are starting to wake up early include winter jasmines, rhododendrons and azaleas. According to Mr. Sullivan, these plants produce a “budget” in the summer that allows them to bloom flowers once a year. Typically, that occurs in late February or March, but because of the warm cycle, the plants are spending their budgets early.

“The plant has been tricked into thinking it’s the next cycle, so it’s opening up those buds,” he said.

With their budgets spent, the plants may not bloom in the spring, and will have to wait until next summer to create their budgets again. If next winter is cold, then the plants will revert to normal and bloom in the spring, he said. . .

His advice for gardeners is to keep watering their spring-flowering ericaceous shrubs, like rhododendrons, azaleas, mountain laurels and camellias, until the first frost arrives. He also suggested that gardeners continue maintaining their early bloomers as they would if they had bloomed in the spring.

“This extra-warm weather doesn’t by itself kill off healthy plants. So don’t worry too much,” he said. “You may see some reduced flowering in some plants next year, but they should pull through for the following year.”'

http://www.nytimes.com/2015/12/25/science/touch-of-spring-in-december-on-east-coast-as-flowers-bloom-early.html?