AUTUMN HUES

Enjoy the colors of fall in your garden and on the trees

The hardy mums and lycoris also known as naked lily or red spider lily bulbs are producing lots of color in our fall gardens.

The big fall color comes from our trees as their leaves change color and prepare to drop and become humus or organic matter to support the plants of next season. Fall leaf color is influenced by day length, weather and leaf pigments. Day length or night length is the most consistent of these factors and repeats virtually the same schedule each year. As the days get shorter, the nights get longer and cooler and trigger a number of biochemical processes in the leaf.

Chlorophyll is the basic green pigment we see in plant leaves and is a key ingredient of photosynthesis, which enables plants to use sunlight to manufacture sugars for food. Carotenoid pigments produce yellow, orange and brown colors in carrots, corn, bananas and daffodils, as well as in many fall tree leaves. Anthocyanin pigment produces red, blue and purple colors in cranberries, cherries, strawberries, red apples, concord grapes, blueberries and plums. Anthocyanin is water soluble and appears in the liquid part of fall leaf cells.

Chlorophyll and carotenoids are present in leaf cells throughout the full growing season, but chlorophyll usually masks or covers up the yellow or orange of the carotenoids. Anthocyanins are produced in the fall when we have bright days and excess plant sugars within the leaves. When day length is reduced, chlorophyll production slows down and then stops. When the chlorophyll is not replenished in the tree leaves, the yellow carotenoids are unmasked and the fall anthocyanins become visible to paint our tree landscape in tones of yellow, orange, brown, red, bronze and even tinges of purple.

The amount and brilliance of fall tree color can vary a lot from year to year based on weather conditions. Temperature and moisture are the biggest factors. Warm, sunny days and cool, crisp nights usually produce the best color. The warm, sunny days produce more sugars into the leaves, and the cooling nights result in the gradual closing of the leaf veins and the trapping of more sugars in the leaf to produce more anthocyanins, which produce the most vivid fall colors. Summer droughts or extended warm fall weather or early hard freezes will lessen the intensity of Oklahoma fall tree colors.

After the fall color, the leaves will separate from the trees and float to the ground. They act as a mulch to protect the tree and surrounding vegetation, and they deliver nutrients back to the soil. Instead of raking and hauling off these valuable leaves, consider using them as mulch over your flowerbeds or creating a compost pile to let them break down into fine humus or organic matter you can add to flower beds when planting next growing season.

Poplar trees will be bright yellow. Oaks produce red and brown colors, sugar maples turn orange-red while red maples turn a brilliant scarlet and most elms just shrivel up and turn brown.

This is a wonderful time of year to work in your garden planting mums, kale and pansies and to enjoy the fall color.

Visit your local parks and drive through the countryside or plan a trip to southeast Oklahoma to get different perspectives of the great fall color nature produces each autumn.