Recommend

Comment

Email this article

Print this article

Get news alerts

RSS Feeds

Share Digg Mixx Linked In Facebook Twitter Delicious

Photos by Andrew Messinger

see all images

Fall in the Hamptons is a very subtle season.

Because we get more sunlight than any other area of the region, along with our very gradual cooldown, the fall color changes are slow to happen here. Upstate, the large maple in my front yard begins to turn around Labor Day and is usually leafless by the third week in September. But it can be six weeks later before a sugar maple in Southampton begins to show the reds and oranges of the season.

As children, we were secure and knowledgeable in the fact that Jack Frost was responsible for the riot of colors that move from our earthbound gardens up into the limbs, branches and twigs above. I have it on good authority though that Jack retired and is now living in Century Village, Florida, where he complains bitterly about the lack of seasons other than dry and wet.

The Native Americans, on the other hand, believed that celestial hunters slew the Great Bear in the autumn and that his blood, dripping on the forests, changed many of the leaves to red. It was believed that other trees were turned to yellow by the fat that splattered out of the kettle as the hunters cooked the meat.

Fairy tales and legends aside, we now know that leaf color changes that take place this time of the year are due to chemical processes that occur within the trees as the seasons begin to move from summer to winter. All during the spring and summer, the leaves served as factories to manufacture foods necessary for tree growth. This food-making process takes place in the leaf in numerous cells containing the pigment chlorophyll, which, from spring on, gives the leaf its green color.

Chlorophyll absorbs energy from sunlight and uses it in transforming carbon dioxide and water to carbohydrates such as sugars and starch. Along with the green pigment, leaves also contain yellow or orange carotenoids, which, for example, give the carrot its familiar color.

Most of the year these yellowish colors are masked by the greater amount of green coloring, but not in all plants. In the fall, however, partly because of changes in the period of daylight and changes in temperature, the leaves stop their food-making process. The chlorophyll breaks down, the green color disappears and the yellowish colors become visible and give the leaves part of their fall splendor.

At the same time, other chemical changes may occur and cause the formation of additional pigments that vary from yellow to red to blue.

Some of them give rise to the reddish and purplish fall colors of leaves of trees such as dogwoods and sumacs. Others give the sugar maple its brilliant orange or fiery red and yellow. The autumn foliage of some trees—such as the quaking aspen, birch and hickory—show only yellow colors. Many oaks, on the other hand, will turn mostly brownish, while beech turns a golden bronze.

One small Japanese maple that I observe every few days will go from a vivid blood red to a near orange and then it seems to go into a yellow phase just before leaf drop. All this is due to varying amounts of chlorophyll and other pigments that are about to peak.

If it’s the red autumn colors that you’re after, these usually take place after a few brilliantly sunny October days followed by night temperatures below 45 degrees. Much sugar is made in the leaves during the daytime, but cool nights prevent the movement of sugar from the leaves. The red pigment anthocyanin is formed from the sugars trapped in the leaves.

Familiar trees with red or scarlet leaves in the fall are red maple, silver maple, flowering dogwood, sweet gum, black tupelo or black gum, northern red oak, scarlet oak, sassafras and sumac. The vines of Virginia creeper and poison ivy can also show striking shows of reds as well, while the invasive bittersweet vine can be a vibrant yellow.

The degree of color may vary from one tree or vine to another. For example, leaves directly exposed to the sun may turn red, while those on the shady side of the same tree or on other trees in the shade may be yellow. Of course, the foliage of some tree species just turn dull brown from death and decay and never show any bright colors.

One of the most striking examples of how a plant reacts to sunlight in the changing of its fall colors is the euonymus alatus, more commonly known as the burning bush.

A mid-sized shrub that makes a great specimen or screening plant, it will tolerate shade to full sun. Come October, the plants growing in the shade show little if any change in leaf color before the leaves fall to the ground. But in full sun, the same plant becomes a vibrantly striking scarlet to flaming red glow that is unmistakable in the landscape.

Another interesting fact is that the colors on the same tree may vary from year to year, depending on the combinations of weather conditions. As an example, when there is much warm, cloudy and rainy weather in the fall, the leaves tend to have less coloration. The smaller amount of sugar made in the reduced sunlight moves out of the leaves during the warm nights. Thus, no excess sugar remains in the leaves to form pigments.