As you drive around the highways and byways, or even just the various neighborhoods, some of the most enjoyable views out the window glass are heavily influenced by the fall colors of trees and shrubs in the landscape. The reds, oranges and yellows of fall show off Mother Nature’s pageantry in its finest form.
Okay, so it’s beautiful, but why, and what can you do to see more of it? Fall color in woody plant leaves is driven by 3 pigments – chlorophyll, carotenoids and anthocyanins. The biggest influencer of their showcase is driven by weather of a given year.
Chlorophyll, the green pigment, is essential for photosynthesis and is most involved in plant health during the growing season. When the day length shortens the temperatures cool in fall, plants are triggered to prepare for winter by producing less chlorophyll and restricting carbohydrate and sugar production to the leaves.
Carotenoids are always present in the leaves but are masked by the green hue of chlorophyll. When chlorophyll production slows, the green colors fade and the yellow and orange carotenoid tints are visible.
Anthocyanins, which produce the red and purple colors, are produced in mid to late summer and early fall when chlorophyll production slows and carbohydrate movement is restricted. Warm days and cool nights enhance the production of anthocyanins, which leads to spectacular color displays.
Fall leaf color varies from year to year in intensity and duration. Long periods of dry weather or the opposite, cloudy/rainy weather will lessen the expression of vivid hues. The best displays of fall color are observed when days in early fall are sunny and mild and nights are cool but remain above freezing.
Medium to large trees that display good red fall color include red oak, black gum, shingle oak, chinkapin oak and sourwood. Small trees with red or color include serviceberry, pagoda dogwood, persimmon and some crabapple cultivars.
Yellow and orange fall colors are commonly observed on medium to large honeylocust, Kentucky coffeetree, river birch, larch, katsura, yellow buckeye, shagbark hickory, yellowwood and ginkgo trees. Smaller species include hornbeam, redbud, Ohio buckeye and paw paw.
Many small and large shrubs also show off red, yellow and orange colors including viburnum, cotoneaster, dogwood, euonymous, sumac, oakleaf hydrangea and seven sons.
