Arborists often claim that all-male plants are “litter-free” because they shed no messy seeds, fruits or pods. In the 1949 USDA Yearbook of Agriculture, which focused on trees and forests, this advice was given to readers: “When used for street plantings, only male trees should be selected, to avoid the nuisance from the seed.” In the years following, the USDA produced and released into the market almost 100 new red maple and hybrid-maple-named clones (cultivars), and every single one of them was male.
It took a number of years for these new trees to mature enough to start to bloom, but eventually they did and with them came more city pollen and the “epidemic of allergy and asthma.” Many of these same trees are still alive and well and getting even larger, and the bigger they get, the more pollen they shed.
Allergies are rarely triggered by small amounts of an allergen; they are initiated by an overdose. Small amounts of pollen exposure are actually good for us, but if we have highly allergenic trees or shrubs in our own yards or lining our streets, we will soon enough be over-exposed. In order to put the brakes on America’s allergy epidemic, we need to reverse the trend toward male-dominated landscapes and stop selling and planting any more of the most allergenic trees, shrubs and grasses in our cities.
and the kicker:
Female trees produce no pollen, but they trap and remove large amounts of pollen from the air, and turn it into seed. Female trees (and female shrubs also) are not just passive, but are active allergy-fighting trees. The more female plants in a landscape, the less pollen there will be in the air in the immediate vicinity. By relying less on males and paying more attention to the allergy-potential of all the plants in our urban landscape, all of us may one day breathe easier.
