If you’ve noticed that the trees in northeastern Oklahoma have taken their sweet time turning colors this fall, you’re not alone in wondering what’s up.
“Turkey Mountain is usually my barometer, kind of my measuring stick, and I noticed it just hasn’t shown its colors,” said longtime Tulsa arborist Don Massey. “Typically the last week of October, first of November is the peak time around here.”
Massey and Cynthia Robinson, horticulture manager for Tulsa Botanic Gardens, have some not-so-good news for Tulsa-area fall color lovers.
“Pretty much what we’ve got is what we’re going to get,” Robinson said.
Massey was a little more hopeful but said forecasts for this weekend in the 20s probably will seal the deal. “A cold snap in that 20-degree range will just scorch those leaves,” he said.
Through consecutive years of drought not so long ago, Tulsans learned all about how lack of moisture can kill any hopes for a colorful autumn. But precipitation definitely has not been in short supply in 2019, and cold weather came on right when the leaves were supposed to turn, so what happened?
Shortened daylight is what first triggers the changes in the trees, the experts said. From there out it’s a matter of the species of trees, moisture levels and weather.
“It tends to be those cool nights and sunny, cool days that will give you the great colors, but there’s kind of an art and science to it,” Massey said.
“Usually water and cooler temperatures are good for fall color, but there is a fine line between too little or too much,” Robinson said. “The recent heavy rains combined with that early freeze essentially slammed the brakes on it right in the middle of it happening.”
Regional temperatures that dipped down to about 27 on Halloween eve combined with the heavy rain and 25 to 30 mph wind gusts that hit Wednesday night killed any hope for improved fall colors.
“I took a picture of the tree in my front yard yesterday because I thought that was going to be about as good as it was going to get for this year, and I was right,” Robinson said. “This morning my yard was covered with a lot of sad, drab leaves.”
Robinson said the colors in the leaves, the pigments, are cold-sensitive, so when the trees with their moisture-laden leaves were caught in below-freezing temperatures, the result was a graying of the landscape.
“Just like putting blueberries or strawberries in your freezer, those colors are not as bright as they were,” she said.
“Cold can do two things to a leaf: It stops it from producing those pigments so you no longer have that little pigment factory, and it also can destroy what’s there or make it look less bright to our eye. That’s how things kind of end up looking gray.”
The trees are fine, she added. They will do their thing and make the transition for winter. A tree doesn’t care how it looks.
“In horticulture you learn it’s such an exact science with factors that are sensitive to light and water and temperature. There is just a sweet spot, and then you get a great visual show for us humans.”
Road trips still are worth taking around the state, and reports from southeastern Oklahoma are that the colors there are a bit more pronounced than around Tulsa — perhaps not as great as other years but still worth seeing, Robinson said.
“It’s kind of like your favorite football team,” Robinson said.
“You can keep cheering for them, but sometimes they just don’t live up to your standards. You still love them, anyway, and you keep waiting for next year.”