Mt. Rainier, Fall

Special to the Herald

If only we could capture the beauty of autumn and hold it to our hearts all winter long.

One of the spectacular features of fall is the wonderful coloring of tree leaves. The more curious among us might wonder just how do leaves develop color in the fall?

The purpose of plant leaves is to harness the sun's energy to feed the tree. They do this with the chloroplasts in leaf cells, which contain the green plant pigment, chlorophyll.

This pigment enables leaves to capture the sun's energy to make sugars and oxygen from carbon dioxide and water. During the growing season, the chlorophyll is abundant.

As the weather turns cool and the days shorten, leaves stop producing chlorophyll.

Some tree and shrub species are genetically capable of taking the carbohydrates left in the leaves and turning them into anthocyanins. These are the red pigments responsible for the reds, pinks and purples in leaves.

As the chlorophyll begins to break down, the newly formed anthocyanins become apparent.

Other plants are not genetically capable of making the anthocyanins. When the chlorophyll breaks down in these plants, the leaves reveal the more stable orange and yellow pigments (carotene and xanthophyll).

Brilliant oranges come from a mix of anthocyanins with the carotenes and xanthophylls. Trees that don't "perform" with remarkable colors usually lose all their pigmentation over a short time.

What are the weather conditions that favor the best fall color? Dry, sunny and cool conditions but not lots of heavy frost are best for bringing out the reds, oranges, and bright yellows.

If plants that are supposed to show spectacular color don't, then their health may be the problem.

Sunlight generally is needed for fall color, especially the reds. If a plant is shaded, fall color will be deficient.

If the plant is experiencing stress, such as from a drought, fall color may be lacking. A plant that is not cued into the advent of fall because it's still growing vigorously from heavy watering and fertilizing late in the growing season also may lack brilliant color.

Can you remember pressing brightly colored leaves between sheets of waxed paper to preserve their colors?

It's one of those experiences of life no one should miss.

Here's how you do it:

Place autumn-colored leaves between two layers of wax paper. Cover with an old towel or cloth rag.

Press the fabric with a warm iron, sealing the wax paper together with the leaf in between. Cut your leaves out, leaving a narrow margin of wax paper around the leaf edge.

Of course that's the old-fashioned way of doing things. You also can preserve fall leaves in your microwave oven. Choose fresh leaves with the brightest colors. You don't want fallen leaves that already have started to dry.

Take separate leaves or small twigs and place them in the oven on top of two pieces of paper towel. Cover them with one sheet of paper towel.

Run the oven for 30 to 180 seconds. The drier the leaves, the less time they will need. Be careful; you could start a fire in your microwave if they cook too long.

Be attentive. Leaves that curl after removal have not been dried enough. Leaves that scorch, were left in too long. Let the leaves dry for a day or two, then finish the leaves with a sealant, such as an acrylic craft spray.

You may get even better results if you use the microwave and silica gel for drying. Place a 1G-inch layer of floral silica gel in the bottom of a cardboard box. Place the leaves lying flat.

Leaves should not touch and should be at least 1G inches away from the sides of the box. Cover the leaves with a 1G-inch layer of gel. Place the uncovered box in the microwave.

You want the microwave to operate at about 200-300 watts, so if your microwave has 2-10 settings operate it at level 4. If the oven only has three to four settings, it should be set at half. If your oven has a high to defrost options, set the microwave on defrost.

Estimated drying time is 2H minutes if you're using a half pound of gel or about 5 minutes for two pounds of gel.

Yet another way to preserve the leaves is to submerge them in a solution of glycerin and water. Use a mixture of one part glycerin to two parts water.

Place the mixture in a flat pan, and totally submerge the leaves in a single layer in the liquid. You'll have to weight them down to keep them submerged. In two to six days, they should have absorbed the liquid and be soft and pliable.

Remove them from the pan and wipe off all the liquid with a soft cloth. Done correctly, the leaves will remain soft and pliable indefinitely.

So take some time with the children in your life. Go out and collect some of the treasures of fall. It's something they'll remember for the rest of their life. I know I have.

-- Marianne C. Ophardt is a horticulturist for the Washington State University Cooperative Extension Office in Benton County.

Copyright 1996 Tri-City Herald. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

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