Yellows save the day
By TOM BUTZLER
What does the fall color of the landscape and winter snowflakes have in common? While they typically occur in different seasons (an occasional overlap), each yearly autumn landscape and individual snowflake are distinct and unique. No two are alike.
This fall, Penn State forest professor, Marc Abrams predicted that the color change would be late and muted. And he was right on the mark. This was a result of the warm, wet weather. While not a terrific display of colors, there were some real gems throwing out color as the cooler weather started to settle in. And it was the yellows that really stood out like I have never noticed before.
You have to go back to some grade school biology to understand the basics of leaf color change. The green we see in spring/summer is because of chlorophyll, a green pigment that captures sunlight and turns it into sugars (food) for the plant. Yellow and orange pigment are always present in the leaf, but we don’t see it as it is masked by the chlorophyll.
As day length changes and temperatures slowly drop, chlorophyll production stops and yellow starts to show. At the same time, reds appear. Different than yellow, red pigments are not masked by chlorophyll but produced in great quantities towards the end of the growing season. But because of this year’s weather, those reds were not produced in large amounts.
But those yellows really showed this year. I saw many plants that looked like glowing orbs in the landscape because of the yellow pigments.
One of my favorite landscape shrubs is the fothergilla. The two main attributes are the bottle brush like flowers and fall color. Reading plant catalogs, the fall color is often described as a ‘kaleidoscope of colors — shades of purple, maroon, burgundy, red, orange, yellow, and gold’ or ‘brilliant medley of yellow, red, and orange.’ The only color showing on my fothergilla was a dazzling yellow.
Ditto for the kousa dogwood. This small tree is noted for its late spring flowering (flowers after our native dogwood) and appreciable fall colors of mostly scarlet/reddish hues. Not this year. The reds mostly took a backseat and let the yellow pigment shine through.
And maybe it was just the year for yellow. While not a big fan of Norway maple (it is a non-native and can be kinda weedy), the leaves turn shades of yellow every fall (contrast that to the bright orange of sugar maples). This year, the Norway’s fall yellow color really popped. In addition, the leaves usually hold on longer into the season whereas most other trees are dropping. So while the rest of the forest and landscape is starting to look brown, the glowing yellow leaves of the Norway maple stands out.
Winter is approaching, and the leaves are really dropping. It is time to look forward to the cold weather and snow; great time to get in some hockey and cross-country skiing.
Tom Butzler is a horticulture educator with the Pennsylvania State University Cooperative Extension Service and may be reached at 570-726-0022.