Autumn is the third season in the garden. The sequence of unfolding foliage colors lasts for two full months from late September to Thanksgiving for those who will look about them. Although bright red maples and glowing orange sugar maples are what's referred to as "peak" color, the more subtle hues wax and wane throughout the season. And each tree and leaf is different.
Once upon a time fall color used to hold mystery and awe. Jack Frost kissed the leaves and they put on a final vain show to please him. The yellows and the purples and the crimsons inspired bewildering wonderment. Today, we understand all about the green of photosynthesis cells fading thereby exposing the anthocyanins (red) and carotinoides (yellow). We know about sugar storage in stems and roots and how cold causes the abscission cell layer at the bottom of each leaf to close, causing leaf drop. Weather computers forecast exactly where "peak" color will be on what day and whether the color will be better this year than last year because we've had more rain.
The Best Color - The best color is always the color at the moment one sees and enjoys it, especially when the sun shines on the leaves, or back lights them, most particularly against a leaden grey sky. I think it was better to watch naively in times of yore as the leaves turned their glorious colors around Columbus Day. Whether because of old Christopher or because the harvest moon cast a spell was worth an little idle, inaccurate speculation or two. It was a season for wonderment suffused in crisp autumn air. In fairness, science though unpoetic, is not all bad. Because of what we now know, we can easily co-opt Mother Nature's accidents and plan a fall garden with two full months of of color. All it takes is a little calculating of the fall color sequence, plus some spaces in which to plant the necessary variety of trees and shrubs.
How to Plan the Fall Colors - In spring, each tree and shrub leafs out in its own time. In fall, it colors in its own time as well. Certain ones always come out together, some early, some late. However, not all trees of the same variety all come out on the same day. Each has it's own time frame depending on location, exposure and water. Several factors affect the time and intensity of fall color. Full sun produces the best color. Cold nights and warm days do too. Cold locations show color earlier than warm, sheltered spots, and where the frosts settle in the lowlands, there is where the fall pageant always begins. Sick plants or branches color sooner than they should which allows us to diagnose the health of the trees. And all need enough water because drought dulls the hues.
The First Trees to Color are the honeylocusts (yellow), redbuds (red/yellow), stewartias (red/purple) and zelkovas (red/orange). Shrubs of early fall interest are blueberry (yellow and red, and long lasting ), forsythia (a blah yellow), and oak leaf hydrangea (orange/purple, in the sun).
The "Peak" (which in northern areas is around Columbus Day in October) includes the red maples (which actually come in all shades of yellow, orange and brilliant red), sugar maples ( more orange), amalanchier, dogwoods (deep red, one of the best ), and sorrel tree - (Oxydendron, a rich scarlet). Vivid red bushes are aronia, burning bush (also called winged euonymus), wild sumac and enkianthus. Witch hazel complements these with its rich yellow color. Virginia creeper vine turns crimson, and noxious poison ivy, turns a muddy red and yellow. If the weather is fair, the colored leaves hang on longer. If it's stormy and windy, the "peak" passes quickly.
Then Another Wave of trees fills the spaces. Dogwoods continue, and are joined by the incredible Japanese maples (glowing orange/red). Also birches (pale golden), common Norway maple (yellow), sweet gum (scarlet), Japanese cherries (varied), and sourgum (scarlet/orange).
The Finale consists of the deep, rich colors of the oaks (scarlet/ mahogany), Callery pears (shades of red) and beeches (mostly golden). In sheltered forests, the yellow leaves of young beech trees often hold for most of the winter.
In my garden the last tree to truly delight the eye is a Japanese red maple (Acer platinoides atropurpureum ) which glows blood red when the low sun shines through the leaves. In Japan, gardens often include such a maple in the western corner to be a "warm spot to sit in the setting sun" says my landscaping book from Kyoto, Japan. The nice thing about the fall garden is that once the plants are established, it's easy and very reliable. The time sequences are quite specific, and the choices are myriad. One can't have them all. However one or two from each stage will produce a long season of color. Then, as the fall garden unfolds, one can try to relive some of that old sense of the mystery and awe.