Garden Column for the Salisbury Post
Darrell Blackwelder
October 25, 2002

    Any one involved in today's landscaping trends always manages the integration of color as a major element in the landscape. Pockets of annuals or perennials splashed into home landscapes as well as commercial landscapes add interest, highlight entryways, and often brighten dull, lifeless areas of the landscape.
    Carefully planned fall color from selective trees and shrubs is a subtle method of adding a spark to the landscape before dreary winter's arrival. The extended drought and warm fall temperatures encourage vivid fall color. However, I already have a few trees that dropped their leaves early with no color.
    Dramatic colors arrive due to the presence of plant pigments other than chlorophyll. Reds and purples are usually the first colors to arrive. Sourwood, dogwood, black gum, even sumac are the first plant life in Rowan County to turn a brilliant red. Red and purple colors are caused by the presence of anthocyanins produced after chlorophyll is destroyed in the fall. Sweet gum follows with deep purple colors while white ash displays a yellowish-purple plume.
    Yellow colors are due to the presence of xanthophylls. This is a yellow to gold pigment present throughout the growing season, but hidden by the green chlorophyll pigment. Tulip poplar, hickory and redbud are a few examples of brilliant yellow color. Vines such as poison ivy and wild grape twist and wrap around trees adding more color. Cultivated vines such as Boston ivy, add vivid reds to drab brick facades.
    Orange is a result of the carotenes and xanthophylls within the leaves. Maples and oaks often have this orange pigment. There are several factors which influence fall color including genetic makeup. Many plants are bred and selected for brilliant fall color: red maples, sugar maples, burning bushes (Euonymous alatus) and ash are examples. Maples such as Acer rubra 'October Glory' and 'Red Sunset' are selected and grafted selections. These culivars were selected for the early, vivid fall color.
    It is not unusual for trees, especially native trees, to have more than one dominant color. Maples and oaks at times have multiple colors. Environmental conditions also have a strong effect. Cool, bright fall days increase photosynthesis and sugar accumulation within the leaves. Copious amounts of stored sugars produce vivid colors just before leaf drop.
Hot, extremely dry weather or excessive rain during the growing season affects leaf color. Heavy autumn rains often diminish color while early frosts or freezes shorten the life of yellow and red leaves.
    When designing your landscape be sure to study not only the color, but the longevity and leaf texture. There is a place in everyone's landscape for fall color. Be creative!
    Darrell Blackwelder is an agricultural agent in charge of horticulture with the North Carolina Cooperative Extension Service in Rowan County. For archived garden columns or other information, visit the Rowan County Master Gardener web site at www.rowanmastergardener.com or e mail Darrell_blackwelder@ncsu.edu or phone at 704-633-0571.

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