by Geraldine Freeman, M.D.
Certain trees and grass for landscaping have a known potential for production of highly allergenic pollens. The closer to the windows and doors of a home or office these grow, the greater will be the exposure indoors. A closed home still allows the entry of pollens through cracks.
Low to middle elevation deserts (up to 4,000 feet, including Phoenix and Tucson): Bermuda, Kentucky blue, annual rye (but not perennial or “winter” rye), fescue, salt, fountain, and pampas grasses; ash, tamarix (salt cedar), elm, juniper or cypress, mesquite trees, male mulberry trees, European olive, as well as pecan, privet, sycamore, black walnut, and possibly palm trees.
High middle desert to high mountainous terrain (above 4,000 feet); Any of the above trees and grasses have allergenic potential. In addition, there are pasture grasses (barley, brome, oat, orchard grass, timothy, and wheat), ailanthus (tree of heaven), aspen, alder, birch, maple or box elder, poplar, and oak trees. It is assumed that Russian olive (not in the true olive family) is allergenic.
Willows are not believed to contribute much allergenic pollen to the environment. Fortunately, given their numbers, pine trees and eucalyptus trees are seldom allergenic.
Posted in: Plants & Landscaping