What time of the year do you like the most? Is it the winter when everything is covered with a blanket of white? Is it the spring when many trees and shrubs show off their beautiful flowers? Is it summer when lawns are green and flowers are blooming everywhere? Or, is it fall when the air turns cooler and the leaves on the trees take on their fall colors in shades of yellow, red, orange and brown?
All seasons have their pluses and minuses, but fall is a very colorful time as the trees and shrubs change from different shades of green to various hues of yellow, red, orange and even brown. It is first important to understand why leaves fall off. All deciduous plants, or plants that lose leaves in the fall have a layer of cells that comprise the abscission layer.
As these cells begin to breakdown at the end of the growing season, the leaf will eventually break off and fall away. How long the color lasts mainly depends on how long it takes for the abscission cells to breakdown and fall away. The longer the process takes, the longer the colors lasts.
How do leaves change color?
The process starts when sunlight time shortens and air temperatures cool down. Less daylight and cooler nights work together to produce more pigments in the leaves. Chemicals and nutrients start moving out of the leaf and into the stem of the leaf. Trees and shrubs use different processes to break down the sugars produced in the leaves into carbohydrates and other foods that lead to the change of leaf color.
Yellow color occurs during this breakdown period. As the production of chlorophyll in leaves stop, two pigments, carotin and xanthophyll, which produces the yellow color, become visible. The pigments are always there, but are masked by the green color of the chlorophyll.
Red colors depend on bright days and cool nights to become visible. Bright light increases sugar production within the leaf, but the cooler nights prevents the sugars from leaving the leaf. When sugar content increases within the leaves, a red pigment, anthocyanin, is produced. Orange is the color that comes from mixing red and yellow together.
Weather plays a role in Fall Color
Depending on the amount of red or yellow pigments produced in the leaves determines the shade of orange the leaf becomes. If the nights get too cool or the days are overcast, you end up with an “off year” for tree color. And a killing frost ends the show completely by killing all the pigments in the leaves no matter what stage they’re in.
The intensity of the colors, especially scarlets, oranges and golds, the weather must be almost perfect along with plenty of soil moisture. The sooner a hard frost occurs, more leaves are killed off before having the opportunity to change color. The color that the leaves turn in the fall depends on the plant’s genetic makeup. If it is important to you to have plants with a nice fall color, inquire about the plants fall color before purchasing.
Trees are a great source of leaf mulch. Instead of raking your leaves, grid them up with your mower and recycle the nutrients back on to your lawn. Leaves do not significantly add to the thatch layer. When leaves start turning color is also a great time to root feed the trees and shrubs in your yard and landscape. Contact your local Spring-Green to add this important service. Your landscape will appreciate it.