Spring is allergy season but do you know why?
Ok, yes, because many people have pollen allergies of one sort or another and as trees and plants begin to bud and bloom, pollen counts can spike. But there is so much more to this – and why do we suffer so much more than people once did?
It isn’t in your imagination that more people than ever have allergies and related asthma and there is a reason – Botanical Sexism.
As an allergy sufferer myself (though dust mites and rodents like mice are my issue) I found this story in the latest issue to be one of the most eye opening pieces we have ever published. Like so many environmental issues this is another one that we have created ourselves and that we can fix. Allergies are so unique to each person, that often times it can feel difficult to pinpoint what is causing the problem and how to minimize its effect but Thomas Ogren explains why and how to begin to reverse our current allergy crisis as well as improve the health of our surroundings. Read on…
Botanical Sexism: Stopping Our Current Allergy Crisis
Back in the 70s, some doctors believed asthma and allergies weren’t medical conditions, but psychosomatic illnesses that existed largely in the minds of ‘hysterical’ women. This posed a dilemma for me as my partner suffered from both and, truth be told, there were times I believed the doctors over my own wife. It would be at least a decade of working as a landscaper and horticulturist before I began to see patterns in the profound effects that various plants had on some people.
For a while, I also had a regular job teaching horticulture and landscape gardening in a maximum-security prison. Curious about some of my theories, I enlisted the inmates to sniff-test pansies, dianthus and variety of other plants in the garden so that I could observe any reaction. Some plants had no effect on anyone, but others – like bottlebrush – caused immediate irritation and sneezing in over a third of the group.
My first hand experiences made me suspicious of the prevailing medical view and I wondered if there were some plants that allergy sufferers could – and should– avoid. For years I studied the connection between landscape plants and allergies and I eventually became particularly interested in the dioecious (separate-sexed) plants, because the male versions of this class of plants were often highly associated with allergy.
In nature, there is generally a balance of male and female plants in any species. But, since the 1940s breeders, arborists and consumers have favored male trees, having been sold on the idea of trees and plants that are less ‘messy.’ Fruits, seeds and pods are shed from many female trees, so a campaign to plant predominantly male trees has been carried out for over a half century. Even the USDA in a 1949 yearbook of guidelines advocated avoiding female trees: “When used for street plantings, only male trees should be selected, to avoid the nuisance from the seed.” The result is that pollen counts in urban and suburban areas are dramatically higher than they once were.
If a tree or a bush is female, that means it doesn’t have any male parts; it doesn’t have any stamens; and it doesn’t make any pollen – that is the job of the male counterpart. Additionally, female plants trap pollen from male plants making them not only hypo-allergenic for people with pollen allergies, but they actually reduce pollen counts. Too many male trees and not enough female trees, particularly in cities and suburbs, has lead to a huge rise in pollen counts in populated areas.
If a tree or a bush is female, that means it doesn’t have any male parts; it doesn’t have any stamens; and it doesn’t make any pollen – that is the job of the male counterpart. Additionally, female plants trap pollen from male plants making them not only hypo-allergenic for people with pollen allergies, but they actually reduce pollen counts. Too many male trees and not enough female trees, particularly in cities and suburbs, has lead to a huge rise in pollen counts in populated areas. As in all things, balance is important and imbalance has consequences.
THE OGREN PLANT ALLERGY SCALE (OPALS®)
Through decades of research, I assembled a list of over 130 criteria that I now use to rank the allergy potential of any individual plant, or cultivar. This system is called the Ogren Plant Allergy Scale or OPALS®. Using a 1-10 scale, landscape plants are ranked, where one is allergy-free, and ten is the most allergenic.
Progress has been, and is still, being made, but there’s so much more to do. Public health departments are now taking notice and some are advocating my work to help with asthma avoidance, but most people still don’t realize that what they plant in their yards can affect the health of their own families.
Even in nurseries, many still don’t know that some plants are separate-sexed and how plants with different flower structures have the potential for causing human allergy.
Fewer still realize the allergy-causing potential of most male plants. Cities continue to plant highly allergic plants, and each year the numbers of those with allergy and asthma continue to climb. There is plenty of more work for me to do on all of this, and I welcome all questions and try to answer all emails from concerned gardeners.
This story is excepted from the Spring issue of PITH + VIGOR. The full story also includes:
Beyond OPALS – 6 Ways To Reduce Allergens in your Garden
Planting A Protective Hedge.
Both of these additional sections can be read online with a digital subscription to P+V or in the print version of paper (both are available here).
(excerpted from PITH + VIGOR Spring 2016)