With cool nights and less sunlight during the day, we just seem to feel fall in the air, but the trees are also starting to feel fall.
Many trees will be starting to show their fall color. Nobody is sure if there is a purpose for trees having fall color, but the color does have a purpose in the summer.
The fall color is always in the leaves; however, it is masked by the green chlorophyll. The chlorophyll absorbs all light from the sun, except for green, which it reflects and we see green leaves. Some leaves have other pigments called chromoplasts, which absorb the green light. During the summer the leaves have a lot more chlorophyll than chromoplasts and the leaves look green. In fall the chlorophyll starts breaking down first and the chromoplasts start to show the fall color.
The trees with the showiest color in the Antelope Valley are probably the Chinese pistache. Chinese pistache has a very bright red fall color. This umbrella shaped tree is a great shade tree, but it is a slow-growing tree.
If you have a Chinese pistache and it does not have good fall color, it may be due to the lack of iron. Chinese pistache do not like our soils and tend to turn yellow due to the lack of iron. Then in the fall this iron deficiency keeps it from reaching its full potential.
Ornamental pears are also turning red. These trees are smaller trees with large roundish leaves. They are also used in landscaping for their abundant white flowers in spring.
Another tree turning a reddish color, more commonly a very dark bronze, is the Raywood ash. These large upright trees have a lacy looking leaf. The Raywood ash is a good large tree that has dark green color all summer with the leaves turning bronze-red in fall.
The most common tree with bright yellow or golden fall color is the Modesto ash. It is a large tree with light green leaves during the summer that turn bright yellow in fall.
The tree with the best fall color is probably the liquidambar tree or sweet gum. There are many different varieties that have been developed for their fall color, ranging from dark red to bright multi-colored trees. However, liquidambars have a hard time growing in the Antelope Valley.
Liquidambar trees prefer higher humidity than what we have in the Antelope Valley. I find the closer they are planted to the surrounding mountains the better they grow — in fact, they grow so much better in Leona Valley and Acton than they grow in the middle of the valley. They also do not like the soil of the Antelope Valley. If your soil is high in limestone or caliche, the plants do not grow very well and the leaves never develop good fall color.
I enjoy the fall color that trees can produce, but I have found in the Antelope Valley fall color can be sporadic. In most years, just as the trees are showing good fall color, we have a very cold night and wind and all the leaves fall off the trees. When I plan a landscape, fall color is not as important to me as other characteristics such as size, shape, growth rate and summer leaf color.