Lexington, KY - Tree pollen counts are extremely high this season. The yellow stuff is on your car, in the air and up your nose. When I moved to Kentucky 14 years ago, I was told that the question was not if I would get allergies, but when. I didn't believe that, but now I wake up with swollen eyes that itch and burn during the day, and I often have a headache in the evening. Surely this is not...allergies?
According to the Asthma and Allergy Foundation of America, the allergy seasons have been getting longer over the years, with six to eight weeks of suffering expected this spring in some areas. This year is being touted as the worst in a long time. Apparently, the cold winter delayed some of the plants from blooming as early as they usually would, so everything is coming out all at once.
And, wouldn't you know it, it's all about sex. Plant sex, that is.
Tiny, dust-like grains of pollen are produced by the male reproductive structure, called the stamen, of all flowering plants. This pollen transports the male DNA to the pistil, the female reproductive parts of the flower, of a plant of the same species. Just a pinch of pollen powder contains thousands and thousands of microscopic pollen grains.
The successful transfer of pollen in and between flowers of the same plant species leads to fertilization, seed development and fruit production. About 80 percent of all plant pollination is by insects; the remaining 20 percent are most commonly pollinated by the wind.
Plant species that are insect pollinated do not have to produce large amounts of pollen because of the efficiency of insects in distributing pollen as they move among flowers. On the other hand, species that depend on wind for pollen dispersal must produce massive amounts of pollen since only a very small amount will actually reach female flowers in that species. Their flowers tend to be insignificant, usually greeny-yellow and small, with no petals.
These wind pollinated species (pines and oaks, for example) are generally the ones that make you sneeze.
"Considering that huge amounts of allergy and asthma are directly caused by excessive wind-blown pollen, it might not be too far-fetched to say that pollen allergy is the most common sexually transmitted disease in the world," says Thomas Leo Ogren, author of "Allergy-Free Gardening" and "Safe Sex in the Garden."
Ogren reports that in the late '50s, between 2 and 5 percent of us had allergies. By 1985, that figure was up to 12 to 15 percent. In 1999, some 38 percent were sneezing and wheezing. Ogren wants to reverse this escalating trend and has developed the Ogren Plant Allergy Scale (OPALS) to help homeowners and landscapers determine the allergenicity of plants. Plants are assigned a ranking on a scale of 1 to 10 (1 being the least likely to cause allergenic reactions in most most people)
According to Ogren's book "Safe Sex in the Garden," the American Elm was at one time a widely used street tree, until Dutch Elm disease killed most of them in the 1950s and '60s. Elms had male and female parts in the same flowers and were insect pollinated, so they shed only a small amount of pollen. Their replacements in most cases were high pollen-producing, wind-pollinated trees, and a huge number of these were male clones. Ogren says that one can actually track the spread of allergy in the United States from the decline of the elms as the Dutch Elm Disease spread mostly from east to west.
Male trees seem to be less messy than females, since they produce no seeds or fruit. Less mess to clean up, and we like our litter-free landscape.
The problem with male clones? Pollen. Male trees all produce lots and lots of airborne pollen. Female plants are nature's pollen traps, our natural air cleaners. But today most of the female plants are no longer in our urban landscapes. Now our mucous membranes, eyes, skin and the linings of our nose and throat provide the perfect moist and sticky target for all of that pollen.
And another thing about male clones: they produce no fruit for birds and small animals to eat, and little or no nectar for butterflies, hummingbirds and honeybees. Over the last 40 years, as the sale of wind-pollinated, male-cloned street trees expanded, it was accompanied by the decline in numbers of the cities' butterflies and honeybees.
Ogren strongly recommends the use of native plants - they are meant to be here and they help to create a balanced ecosystem, reducing the need for water, herbicides, pesticides and fertilizers. He says that "many of our most allergenic plants commonly used in landscaping are indeed native to North America. However, it is the gender manipulation of these plants by commercial horticulture that has caused most of the huge increases we are now experiencing with allergy problems."
For more information about allergy-free gardening, take a look at Ogren's two books.
A last word from Thomas Ogren: "Allergy-free gardens and landscapes, with their reliance on female and insect-pollinated plants, may indeed be a bit messier. But they will also bring us less allergy, less asthma, cleaner air, and more birds, honeybees and butterflies."