Looking for signs of spring? Look no further than the red maple
This is the time of year we look for signs of spring — any signs of spring. The ice, the cold, the snow — they make us long for any signal that the kinder seasons are on the horizon. And the slightest hint is enough to send us to the garden center, looking for tomato transplants.
Well, we’re not the only ones who respond to little signals — plants do the same thing.
In front of my house stands a mediocre specimen of the locally native red maple, Acer rubrum. It’s a pretty nondescript tree most of the year with medium green leaves, casts a nice bit of summer shade and provides OK red and yellow fall color. But in early spring it puts on quite a floral show that is one of those spring signals I look for every year.
Now the flowers on red maple don’t hold a candle to your garden variety cherry, magnolia or redbud. They’re small, apetalous (plant geek for 'no petals') and range from kinda reddish to green/brown. Not a flower that inspires many poets.
Greenspace:Being a gardener in Kentucky isn't so bad. Here's why
But when I burst in the door and announce to my wife "the red maples are blooming, the red maples are blooming," she gives me that look that says, “oh, how funny you plant people are with your little Latin names and goofy maple flowers.”
I guess it’s the same look I give her when she gets all misty eyed over some horsey dressage move that nobody on earth could see — except a similarly goofy horse person.
But really who can compare. These are the first tree blooms to make their show each spring! That’s way cooler than some horsey thing.
The thing about red maples, and other trees as well, is that they have a series of systems that track changing day-length (photoperiod in plant dweeb talk) and temperatures. Each winter and early spring, as photoperiod lengthens and temperatures rise, these internal systems let the plant know when it’s time to start doing their thing.
Rising temperatures can’t do it alone. Lengthening photoperiod can’t do it alone. It is both signals working together that tell a plant when it’s time to perform.
But there is a complication in this system. Red maple is native from Florida all the way to Minnesota and New Brunswick, Canada. And it’s no secret that temperature profiles this time of year are way different in Florida and Minnesota. But photoperiod profiles differ across this region as well.
Greenspace:What happens in your Kentucky garden during really cold weather
If you remember your freshmen earth science class, you’ll remember that at the equator you’ll find 12 hour days and nights year round. At the poles, you have essentially the opposite, one six month day and one six month night. This year at 7:46 a.m. on March 23, the sun will set at the South Pole for six months. It will rise again at 10:43 a.m. on September 21.
Now Florida and Minnesota aren’t exactly the north and south poles, but you get the point. So it’s not surprising that red maples that evolved in Florida and Minnesota would react in a slightly different way to those key environmental shifts. They’re the same species but with some quirky differences here and there. And you wouldn’t expect a Minnesota red maple to feel particularly at home in Tallahassee.
It’s sort of like dropping a Bostonian in Savannah. They’d be instantly identifiable as not quite at home — not only for the Super Bowl inspired long face, but because they’d be ordering a Sam Adams and clam chowder rather than corn puddin’ and sweet tea.
Red maples from down south don’t fare well in the north because they leaf out too early in spring and keep growing too late in the fall — all because they think they are reacting to Florida conditions. Those from up north don’t get enough cold weather to break their winter dormancy so they just sit there and flounder.
So this spring, when the right time comes around, order yourself a sweet tea and a clam chowder and celebrate the subtleties of the season.
Yew Dell Botanical Gardens, 6220 Old Lagrange Road, http://www.yewdellgardens.org/.
