The Herbal Bear Newsletter - September 2006

In this months issue:

• Why Do Leaves Change Colors?
• American Ginseng - Growing Observations
• Herbal Bears' Pop Quiz
• The Herbal Bear's Fall Classes

Why Do Leaves Change Color in the Fall?
By Ursula Basch, Herbal Bear 

As Autumn approaches, we are starting to notice the leaves  changing color.  Have you ever wondered why this happens? The leaves of trees and plants in fact have many colors.  The reason most plants are green in the summer is because green chlorophyll, the substance that lets plants turn sunlight into chemical energy, is abundant in the leaves. Cooler temperatures and shorter days, serve as a trigger to a tree that it needs to start getting rid of its leaves. Fall brings less sunlight and together with cooler temperatures,  the process of photosynthesis slows,  causing chlorophyll in the leaves to break down. 

If Chlorophyl is Green, What About the Other Colors?
The colors red, and purple, come from anthocyanins. The oranges are a combination of pigments: red anthocyanins, and the yellow cartenoids and xanthophylls. These anthocyanin pigments protect the leaf, acting like a kind of sunscreen. They keep the sun's radiation from breaking down the leaf pigments too quickly, allowing the tree more time to get the nitrogen and other nutrients out of the leaf and recycle it back into the woody part of the tree for next year

Why are Some Autumns More Colorful Than Others?
Autumn leaf coloration each year is different. Depending on the weather, there will be different colored chemicals in leaves. Green chlorophyll disappears fastest when the autumn weather has bright sunlight and cold days. This quickly exposes the leaves' orange and yellow pigments. Dry weather concentrates sugar - which speeds up manufacture of red compounds. So colorful autumns depend on the weather.

Different Trees Turn Different Colors
Trees with yellow leaves include: Birch, Poplar, Basswood, Beech, Witch Hazel, and Hickory. The trees which show the best red colors are: Red Maple, Sugar Maple, Red Oak, Dogwood, and Sumac.

The Northeast Has Some of the Best Fall foliage!
Because of its climate and the variety of trees, the Northeastern United States has some of the best fall foliage in the world. Even in areas where the climate is similar, such as areas of northern Europe, there are no Maple trees. Most of Europe's fall foliage is yellow! Maples trees, especially Sugar Maple and Red Maples, have those special red chemical compounds and together with our other varied tree species produce a variety of color resulting in the spectacular foliage displays found throughout the northeastern USA.

Growing Observations on American Ginseng
by Bob Beyfuss, State Ginseng Specialist for Cornell University Cooperative Extension

This has been an interesting year for ginseng growers in New York State. A grower in central NY wondered why plants in a certain area of his garden emerged earlier then others. He wondered if there was some genetic difference amongst his plants. Like all good growers, he decided to experiment by transplanting some plants into the area where they always seem to come up early. When the transplants also emerged early he knew that it was the difference in site and not the plants that caused the difference. One site was just warmer then others. Ginseng emergence dates may be weather controlled but flowering time in any given season probably has genetic influences also. I have transplanted wild ginseng from Georgia to Maine into a common garden near Cornell and there are surely regional differences

Adequate soil moisture is very important for optimal ginseng growth but too much moisture can create some serious problems as can late spring frosts. Perhaps the most common disease of ginseng seedlings is "damping off" which may be caused by several different fungi. "Damping off" is characterized by seedlings developing a constricted area right at soil level which causes them to topple over and die. Overcrowded, over fertilized ginseng plants mulched with hay or straw are most susceptible to this disease. Ginseng does not like fertilizer and does much better if planted in areas that are naturally fertile. Once "damping off" occurs there is little that can be done to stop it without resorting to serious chemical warfare. Better to AVOID problems such as this by proper spacing of seeds and thinning overcrowded stands.

Straw mulch also attracts slugs, but they are also common where no straw is used. I consider slugs the number one enemy of new ginseng plantings. Lay flat boards, watermelon rinds or grapefruit halves in your growing area and look underneath them for slugs frequently. If you find slugs you must deal with them promptly or risk loosing all your small plants. There are organic solutions such as iron phosphate sold as "Escargo" and "Sluggo" Older ginseng plants can tolerate more slug damage then seedlings but they are still damaged and every hole in a leaf serves as a spot for possible fungal infection by Alternaria blight.

Alternaria blight does not usually show up until mid to late June. The first symptoms are yellow spots on the leaves that eventually turn brown. Two year old and older plants are more susceptible then seedlings. Blight causes premature leaf drop and loss of the season's growth. Organic growers may use Bordeaux mix or copper hydroxide compounds. Fungal diseases and insects also have the nasty habit of becoming immune to the pesticides that are used to control them if the pesticides are used over and over again. Once again try to avoid problems by providing good air circulation and properly spacing plants. Ideally, each ginseng plant should have enough space to not have its leaves touching it's neighbor.

Phytophthora root rot is the most dreaded of all ginseng diseases. It is a water borne, highly contagious fungal disease that devastates ginseng in soggy ground. The plants first wilt and by the time you realize something is wrong, the whole root is rotted away! I almost guarantee you will have root rot if you plant ginseng in a poorly drained soil. Many commercial growers apply the fungicide Ridomil 5G as a preventive measure before the problem occurs. I know of no alternative organic substitutes. Ridomil is quite expensive and in the long run it is much preferable to find a well drained site.

I guess the message from all the above is that proper site selection from the beginning is the best way to avoid problems later on. An ounce of prevention is worth many pounds of expensive chemical "cures". Learn everything you need to know about growing ginseng at this years Catskill Mountain Ginseng/Medicinal Herb Festival!

Bob Beyfuss is an instructor for The Herbal Bear's Botanical Medicine Program.
To learn more about the Botanical Medicine Program, click here.
To find out more about Bob Beyfuss, click here.

Click Here to learn more about the Catskill Mountain Ginseng/Medicinal Herb Festival

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