By Faith Peppers
University of Georgia
About one in five people suffer from allergies, many of them plant related. That doesn’t have to keep you indoors come spring, garden experts say.
“Flowers, trees and lawn grasses in our backyards produce billions of pollen grains each spring,” explained Walter Reeves, host of Georgia Public Broadcasting’s Gardening in Georgia.
“According to data collected by the Atlanta Allergy Clinic, Georgia's pollen season peaks in early- to mid-April, recedes in mid-May and resurfaces in mid-August.”
That’s also prime Georgia gardening season.
“Some plants are pollinated by insects, but other plants shed pollen into the air,” Reeves said. “Instead of landing on the intended flowers, these tiny particles are inhaled by people. They adhere to the linings of the nose, throat and eyes. Our bodies release a chemical [histamine] that induces allergic symptoms in sensitive individuals. The results: sneezing, coughing, itching and watery eyes.”
Plants pollinated by insects tend to have large, sticky pollen grains that aren’t airborne. These don’t pose as many problems for allergy sufferers.
Gary Peiffer, a UGA Cooperative Extension agent in DeKalb County, defends one tree: “Pine pollen is often accused of causing allergies, but it isn’t a potent allergen. The pollen is too large to go deep into the respiratory tract. Oak, birch and elm are the real culprits.” Although pollen can travel many miles, most tends stay in the area of their origin.
“An oak tree in the yard can expose the homeowner to 10 times more pollen than an oak tree a block away,” Peiffer said. During the height of the pollen season, there are often thousands of pollen grains in every cubic meter of air. Most airborne pollen is so small it’s barely seen.
“The amount of pollen in the air varies mile to mile and hour to hour, depending on local vegetation, wind direction and velocity and other weather conditions,” he explained. “Pollen counts are higher on sunny, dry days and lower on cool, cloudy days, or after a rainfall. Pollen is lower at night when winds are calmer.”
Planting recommendationsSome landscape plants known to cause problems for allergy suffers include roses, star jasmine, citrus trees, eucalyptus trees, narcissus, rosemary and gardenia.
“One way to select ‘sneezeless’ plants is to examine the flowers,” Reeves said. “Plants that produce the most frequent allergies are wind-pollinated. Their flowers are drab, inconspicuous and often in clusters or tassels. Frequently, wind-pollinated plants have separate male and female flowers, or entirely separate male and female plants.”
Most colorful and showy flowers are safe.
“They are insect-pollinated and their beautiful petals serve to attract bees and other insects,” he said. “Their pollen grains are usually heavy, sticky and have a variety of surface structures, such as spines. The pollen grains can securely attach to the insect and aren’t easily picked up by wind currents. These pollens seldom cause allergies.”
Lawn and weed alertPeiffer offers this advice on lawns:
“Ragweed is the dominant allergy producer in the fall,” Peiffer said.
Other common allergy-causing weeds include grasses, nettle, dock, plantain, tumbleweed, pigweed and lambs quarter.
(Faith Peppers is the director of public affairs with the University of Georgia College of Agricultural and Environmental Sciences.)