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Horticultural Myths

What is a myth? Webster defines a myth as a falsehood; an unfounded belief. Let us talk about some horticultural myths.

"Walnuts with onions, salt and honey are good against the biting of a mad dog or man, if they are put on the wound." Tom Gerard The Herbal, 1633

Myth: Planting marigolds in the vegetable garden will repel insects.
Fact: Some research shows marigolds have an effect on certain soil-dwelling nematode populations. Some species of marigolds release compounds from their roots, which can be toxic to some of the microscopic worm-like organisms that destroy the root systems of plants. This seems to occur only if you plant a solid, dense area of marigolds and allow them to grow for about two months. They are then chopped down and the roots and cuttings turned under (best in the fall). Visible results can take up to four months to appear if the right combinations of marigold and nematode species are used.

During the Civil War, a detachment of soldiers came upon a peach orchard. After eating as many as they could, each one took several peaches and placed them in his pockets. Later in the day the soldiers were all killed. They were buried, and later a peach tree is said to have grown out of each burial site.

Myth: The foliage on spring bulbs must be left to die back naturally in order for the bulb to bloom the following spring.
Fact: Bulbs exhaust their nutrient reserves when they bloom. Plant leaves replace these nutrients. However, it is not necessary to wait until the leaves die back before removing them from the plant. Three to six weeks after the flower has died, enough nutrients have been stored in the bulb for the next spring's bloom.

Myth: Goldenrod causes allergies. Fact: Goldenrod has been falsely accused for years of causing sinus congestion and itchy eyes. The culprit is ragweed, which blossoms at the same time.

Myth: It is a good idea to buy lady beetles by the gallon for releasing into the greenhouse and garden. Fact: Buying lady beetles by the gallon to release into the greenhouse and garden is NOT gardening money wisely spent. Most beetles take flight a short time after being released.

Myth: All bugs are bad.
Fact: Bugs are NOT bad. Most insects, spiders, and other "creepy crawlies" are either beneficial or harmless. The vast majority are part of a healthy environment and do not carry human diseases or seriously harm plants. Less than one percent of insects are true pests. On the plus side, insects produce honey, silk, and wax, are pollinators of a multitude of plants, are predators; take part in the decomposition process; and are food for a number of animals and birds.

Myth: A colder-than-normal winter will kill bugs in the garden so there will be fewer insect pests the following growing season.
Fact: Cold weather does NOT kill bugs. Insects are tough and will take all the cold that Mother Nature can give them. Some species' bloodstreams contain as much as 50 percent glycerol, natural antifreeze!

Myth: Pelargonium Citrosum 'Van Leeni', the so-called mosquito plant, repels mosquitoes. Fact: This plant, a cross of lemon grass and a scented leaf geranium, grows to about 5 feet high and sends a scent of lemon about. Research has concluded it does not repel mosquitoes. Neither do castor beans.

Myth: Used tires release chemicals into the ground.
Fact: For years gardeners planted seedlings in used tires which collected and released heat, helping to make earlier spring planting possible. For a period organic gardeners stopped using them, fearing the tires were releasing unwanted chemicals into the ground. This has been disproven.

Myth: Overhead-watering acts like a magnifying glass on leaves burning the leaf. Fact: Droplets do magnify a bit, but not enough to warm the leaves burning them.

Myth: Plants grow well when exposed to classical music.
Fact: A common corollary is that plants grow poorly when exposed to loud rock music. Another related myth is that plants grow better when their owner talks to them. The problem with these ideas is that plants have no nervous system, and thus have no organ for detecting sound. The only way that loud music, or loud sounds of any kind could have an effect on a plant is if the sound were loud enough to cause physical damage. Such sounds would have to far exceed the sound of a jet engine at close range.

Myth: When it comes to garden chemicals, if a little bit is good, a lot is better.
Fact: This myth is not only false but also dangerous. Doubling or tripling the dose of any garden chemical can have disastrous results. Weed killers used in this manner can injure plants you never intended to harm, not to mention leaving long-lived residues in soil. Over-use of insecticides may kill beneficial bugs, harm plants and render vegetables unfit for consumption. Doubling the recommended rate of any pesticide increases the chances of poisoning people by inhalation, absorption through the skin, and by other routes. Fertilizers used too heavily will burn plants, prevent seed germination, and contaminate water resources. Even organic fertilizers such as manure can cause harm if you use too much. With all chemicals, the responsible gardener should READ THE LABEL.