10/06/04
The Colors of the Seasons
By: Donna Couch
A big part of the excitement of fall is the great show of colors. Of course,
we have many beautiful fall blooming plants such as mums, asters, salvias,
and pansies that bring yellows orange, burgundy, and bronze blooms. There are
many bushes that bloom in spring that now are alive with bright colored berries.
But
the color that people think of at this time of year really comes
from the changing colors of the leaves. You can take a drive
down a country road or though a residential area and find trees
and shrubs alive with color in the fall. Where does this color
come from? Why do some leaves noticeably change color and some
just seem to turn brown and fall off?
According
to the Department of Agriculture, leaves of plants and trees
contain pigments that give them their color. Of course, I’m
sure we learned all of this in Biology at WHS, but for me, that
was more than a couple of years ago. And since this is one of
my favorite times a year, I wanted to refresh my memory on this
subject, so to the internet I go. And to save you the time and
trouble of moving that mouse around, I’ll share with you
what I discovered.
Chlorophyll
is what gives leaves their green coloring. I did remember that
from Biology, so I knew I was on the right track. Needless to
say, chlorophyll is very abundant in plants and trees in summer,
because it is used to capture and retain sunlight for photosynthesis.
During the summer, the chlorophyll is so high that the green
color is so great that all other pigments are covered in the
leaves, and not allowed to show through.
It’s
all those other colors that brought in the really big words.
Yellow, red, orange and brown colors come from carotenoids. These
are fat-soluble pigments and are found in such fruits and vegetables
as carrots, citrus fruits and peppers. They also account for
the colors found in flamingoes and salmon. The beautiful blues,
reds and purples come from anthocyanins. This is also the pigment
that gives blueberries, raspberries and grapes their color. In
fall, chlorophyll production slows down, because the days grow
shorter, reducing the amount of light that the plants absorb,
and the length of time each day they can absorb the light, thus
allowing the other color pigments to show through. Excess plant
sugars during the fall help to contribute to the vibrant hues
of autumn.
Also
contributing to the color scheme of nature are temperature and
moisture. And since these vary from year to year, you never have
two autumns the same. Once the temperatures begin to drop from
our dog days of summer, it seems that several sunny days in succession,
coupled with cool nights result in the most spectacular color
show.
And
of course, the final color result is very specific to the type
of tree. Across our nation, there are many varieties of trees
that are well known for their notable colors. In the Rockies,
where Aspen are a popular native tree, you will see vast mountainsides
of golden yellow. Birch and black maple also produce a golden
canvas. Dogwood trees, commonly found in the south, light up
neighborhoods and countryside with beautiful shades of purplish
red. Sugar maples become an orange-red, while a red maple turns
a brilliant scarlet, thus the origin of their name. Oak trees,
which are common in our area, remain green longer than most,
sometimes even after others have lost their leaves, turn red,
brown or rust. Another popular tree in Parker County, the Bradford
Pear, turns red with tinges of yellow.
While
were talking about trees, don’t forget, autumn is a great
time to plant native trees and shrubs, as they will sometimes
have a better chance to take root in the cooler weather. However,
just to be on the safe side, make sure you mulch well, at least
six to eight inches of mulch over the root ball, but about two
inches away from the tree base. Adding compost to the soil before
backfilling the hole will help the plant be nourished throughout
the start of growth. Make sure the tree gets enough water throughout
the fall and winter months, especially if the season is dry.
Go
for a drive, take a walk, work in your garden. Enjoy this wonderful
fall weather. It won’t be long ‘til you’ll
be wishing it was warm again, once winter gets here. Until next
time, happy gardening!
