Just as they do every April, the fruit orchards at Larriland Farm have donned their spring finery.
The plum trees at the pick-your-own place in western Howard County sport brilliant white blossoms, while the peach trees are decked out in bright pink.
Thing is, it's still March.
Spring came early to Maryland, thanks to a run of unusually warm weather that awakened flowers, trees, birds and bees weeks ahead of schedule across much of the eastern United States.
Larriland's fruit trees are flowering about a month earlier than usual, according to Lynn Moore, president of the family-run fruit and produce farm in Woodbine. Farther west in Thurmont, the owner of Catoctin Mountain Orchards says his trees are blooming three weeks early. Wine-makers across the state report their grape vines are starting to bud out two to five weeks sooner than normal.
That may be unusually early, but spring seems to be getting a jump on itself more and more. Climate experts call it "season creep," with winters getting warmer, and growing seasons longer, on average.
"It does seem like springs are getting weirder and wilder around the nation," said Jake Weltzin, a biologist with theU.S. Geological Surveyand director of the National Phenology Network, which is tracking the influence of climate on plants, animals and landscapes. "You see a lot of variation from year to year, but you see this trend toward earlier springs."
The trend doesn't appear to be global, but in temperate regions researchers have found clear shifts over decades in the timing of first appearances of flowers and leaves.
Scientists reported last year in the Journal of Climate, for instance, that tallies kept since 1950 in western North America show buds and blooms are showing up 1.5 days earlier, on average, per decade.
In the Northeast, other scientists working from detailed records kept by 19th-century naturalist Henry David Thoreau found that some species he tracked in eastern Massachusetts 150 years ago now flower up to 10 days sooner.
And closer to home, Smithsonian scientists determined over a decade ago that 89 of 100 native plants in the Washington-Baltimore area were blooming about 4.5 days earlier than they did in 1970 — and that Washington's famous cherry blossoms were popping out a week sooner.
Long-term weather shifts can last years or even decades. And recent research suggests that some of the advance in spring flowering may be attributable to the "urban heat island effect," where paved-over areas generally are warmer than the countryside. A University of Maryland scientist and colleagues noted that growing seasons are longer within 20 miles of cities in the Mid-Atlantic region.
Most climate-change models predict a 3-to 8-degree-Fahrenheit increase in average annual temperatures by the end of the century. But some scientists say a warming planet may be contributing to weather extremes seen lately, including early onsets of spring.
"Even though you can't say any particular year that 'this is due to climate change,' the fact you have these really unusual conditions suggests it would not be that unusual without the increase in temperatures that the climate is causing," said Donald F. Boesch, president of the University of Maryland Center for Environmental Science, who helped write a National Academy of Sciences report series called "America's Climate Choices."
While many may be inclined not to worry about the future and simply to relish the extra balmy weather, it produces anxiety for those who make a living raising fruit. Fruit and nut growing was a $19.4 million business in Maryland in 2007, the latest year for which the U.S Department of Agriculture has census data.
"It puts you more at risk," said Moore, whose farm produces berries, cherries, apples and a variety of other produce. The flowers could wither if a frost hits, and fruit won't form. It's happened before — when warm spells triggered early peach blossoms a couple times in the 1980s and '90s, she said, she lost practically the entire crop to frost.
"We all are concerned," said Robert Black, owner of Catoctin Mountain Orchards. "We're just so far away from being out of the frost period."
The National Weather Service in Sterling, Va., acknowledged Thursday what's obvious to anyone who's stepped outside — the region's "incredibly warm" temperatures have triggered an early growing season for most of the Baltimore-Washington area.
Still, the forecasters warned that blooming fruit trees are vulnerable because temperatures typically dip into the mid-30s and below for at least a few nights in April. And there was even a frost in the Shenandoah Valley in May 2010.
That worries grape growers and wine makers as well. After an extremely mild winter in mountainous Garrett County, Paul Roberts of Deep Creek Cellars said that it looks like his fields may experience "bud break," when leaves start emerging from the vines, any day now. That's the third year in a row of early growth, and the earliest he's seen in 15 years of cultivation there.
"For us, our historic first day of the growing season was May 1, though in 2010 it was April 14 and last year it was April 8," Roberts said.
While the start of growing season may be advancing, it's not clear that the threat of frosts is moving with it. David Inouye, a University of Maryland biologist, said that in Colorado, where he conducts research in summer, there haven't been decent crops of apricots or cherries for a few years now because hard frosts nullified early springs.
"If you get bud creation, even bud break, and you have a late frost, those vines are going to be damaged and your ability to produce a legitimate output for the season is very much in jeopardy," said Don McClure, CEO of Maryland Vineyard Management, which oversees about 100 acres for various growers in the central part of the state. McClure said he lost about 30 percent of his Chardonnay one year because of a frost that hit May 8.
Early flowering brings other concerns as well.
"It probably means insect problems will be worse," said Ed Boyce of Black Ankle Vineyards near Mount Airy. With a longer growing season, fruit-eating and -spoiling insect pests can reproduce more often.
Some fruit growers believe they're witnessing a climate-change effect already, while others aren't so sure.
"Wineries in general, there's not much controversy about climate change," said Boyce. "We all see it."
Warmer temperatures would be good for the grape vines, he added.
But climate models also predict more precipitation and extreme weather events — heavy rains like those that inundated Maryland during Tropical Storm Lee hurt the grape crop, vineyard owners and managers say.
Black, who's 60, said weather extremes come and go. He recalls a severe drought in the 1960s, for instance, that hit the family's orchard hard.
Moore said she thinks climate can only be judged by looking at a century's worth of weather, though she acknowledged there seem to have been more extreme storms lately. But she said she's too busy getting fields ready to spend much time pondering whether it's a weather cycle, or something more lasting and drastic.
"Fortunately, I don't have to make predictions," she said. "I have to deal with it now."
The farm's first crop, strawberries, normally are ripe for picking by late May, she said, and the earliest they've been ready for the last 30 years has been May 19. Asked if they'll be red and juicy by then — or sooner — she said: "We'll see."
March average: 43.6 degrees
March 2012 average, through March 22: 53.9 degrees
Record high for March: 90 degrees on March 29, 1945
Most recent below-freezing temperatures: March 11
Normal last frost date: April 22