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This article appeared in the April 2002 web issue of Horticulture Update,
edited by Douglas F. Welsh, Ph.D., and produced by Extension Horticulture,
Texas Cooperative Extension, The Texas A&M University System, College Station, Texas.
Gardening With Allergies
By Cynthia W. Mueller
Galveston County, Texas
If you or a member of your family are among the millions of Americans who suffer from plant allergies, but still love gardening, there are ways to lessen the amounts of pollen, fungus spores and other plant-based allergens in your home/garden environment. Take steps to create low-allergen plantings.
Allergies to pollen
Pollen spores are one of the main sources of allergies, and are shed from male trees, weeds, ornamentals and grasses in your garden or neighborhood by the billions. There are two basic types of pollen: one is lightweight and depends on wind dispersal to travel to a receptive female plant of the same species, and the other is heavier, generally stickier, and relies on the visits of insects to the flowers for fertilization. These flowers are usually colorful and attractive to insects. Examples of trees depending on bees are ornamental and fruiting pears and peaches, red buds, and many flowers found in the garden. Still other plants are self-fertile and not much pollen transmission or exchange occurs at all.
Allergies to fungus
Clouds of pollen can swirl upwards on wind currents and drift for miles. Ragweed samples have been collected 400 miles out to sea and two miles high in the air. Chemical makeup differs among plants, causing stronger or weaker allergic reactions, and heavier pollen such as that of pines may fall straight down to the ground rather than drift extensively.
Although gardeners cannot stop all movement of pollen, it is possible to study the trees and ornamentals in the home landscape and select those with less potential to cause problems. Bermuda and Johnson grass are high on the list of offenders, as well as nearby unmowed pigweeds and ragweeds and their relatives. Thomas Ogren, in his recent book Allergy-free Gardening: The Revolutionary Guide to Healthy Landscaping, comments on the overuse of male trees and shrubs in the modern American landscape. These have been promoted as an improvement over the messiness of female trees which shed too many fruits or seeds and are more “litter-free.” Some municipalities have even passed ordinances prohibiting the planting of female varieties, so that there may actually be more pollen than before in our neighborhoods. Good examples of female plants suitable for Texas would be yaupon or Burford hollies and the Chinese pistache, which have clusters of beautiful berries in the fall. Ogren’s book has detailed lists of suitable plants for low-allergen gardening.
Take care to rake up and compost dead leaves lying under shrubs and use less bark mulch or chips which may harbor fungus. During wet springs clouds of spores can actually be seen rising like smoke from moldy twigs or fruit. Cut back or thin out hedges and trim lawns closely to reduce pollen and mold spores.
To lessen chances of allergic reactions, garden in the morning or late afternoon when pollen is higher in the sky, or on cloudy or cool days when it is not as prevalent. Use a mask when mowing, and change clothing and bathe after working outside. Use caution when sweeping or raking up oak catkins. At times when willows, cottonwoods or sycamores are noticeably shedding, stay inside out of the garden.
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