In the past week we have witnessed blazing colors in the trees around us, and now that beauty has fallen to earth. Both events offer an opportunity to learn more about this annual spectacle. Today I’m sharing a good article about the science of fall color and a video of what to do with all that color when it “falls to earth.” Both are courtesy of K-State Extension.
ORNAMENTALS- A Time for Stunning Fall Color
“Four seasons. Aren’t you glad to live in a part of the world that gets to experience the wonder and joy of environmental change? Winter, spring, summer…fall. The rhythm of our lives is partly set by the events that we anticipate and celebrate in each quarter of the year. I think fall is my favorite season, however, I might say the same thing when spring comes around next year. I love that we get to experience the changes and find new things to enjoy with each cycle. What a fantastic way to live.
Fall is incredible! Changing leaf colors, cooler temperatures, pumpkins, mums, s’mores, hayrides, and the fragrance of my neighbor’s wood-burning stove all signal the changing season. Pretty soon we’ll be basking in the glow of family and friends at the Thanksgiving table, enjoying the bounty of the season of the past summer.
So, how will our fall leaf color turn out this year? In stark contrast from the last several years, we have had great weather and decent rainfall in 2013. While we may still lose some plants to the stresses caused by the weather in the last few years, the ones that are thriving will reward us with a great show of fall color.
This year as I’ve marveled at the beginnings of fall leaf change, I’ve been thinking about what’s actually happening inside the plants. It’s the plant nerd in me—I’ve just got to know what’s going on inside those little cells to give us such a great gift. So, pull up a chair and tighten your bootstraps—I’m gonna toss a few big terms at you today. Senescence is the technical term for the developmental processes that lead to leaf color change and death. In the case of autumn leaf color change, these processes are initiated by environmental cues: day length shortens (less sunlight to photosynthesize) and temperatures cool (signaling the plant to protect itself from freezing, cell-busting conditions). Senescence is a normal process that is controlled by the plant’s own genetic program.
Evergreens have to stick it out over the winter with their exposed leaves/needles, but deciduous plants make a costly choice to drop all of their leaves for the winter and grow new ones when environmental conditions are favorable in the spring. If leaves of deciduous plants are genetically programmed to die, what are they doing with that huge investment of plant tissue? Well, I’ll spare you the glory of the gene- and enzyme-driven description and share the simple one. Essentially, the plant is taking all of the valuable resources (water, sugar, minerals, proteins, carbohydrates, amino acids, etc.) out of the leaves and storing them in the main body (stems and roots) of the plant until it’s nice enough to play outside again.
When this change (senescence) starts to happen, the chloroplast is the first organelle in the cells to deteriorate. Chloroplasts are full of the green pigment chlorophyll, which is used in photosynthesis. When the plant stops making new food with photosynthesis it doesn’t need the chlorophyll anymore and breaks it down for storage. With the green gone, we can now see other pigments reflected in the leaf surface (red, purple, orange, yellow). As each plant is controlled by genes telling it when and how to begin storing resources, so too are the primary senescence colors for that genus and species of plant. That’s how we can recommend certain plants for red, purple, orange and yellow fall color.
Breeders spend many years choosing plants with superior fall color. Selection for this trait can only occur once per year, thus finding great plants is a slow process. Fortunately, new cultivars of trees and shrubs that consistently express good fall colors are common. Isn’t fall in this part of the world great?
One last thing…the ‘Flamingo Pineapple’ mum I tried this year? Total success! (Cheryl Boyer)”
Here’s the video link; http://www.youtube.com/watch?v=7IX9bEpWpcs