I took a relaxing boat ride on the Perquimans river recently and noticed copious amounts of tree pollen floating on the water. I suspect much of it was from bald cypress trees since most loblolly and longleaf pine pollen has been shed already.
Watching these yellow masses flow down the river made me think. There’s a lot of pollen that never hit the target. It also made me realize why some pollen causes more problems than others.
Pollen is the male gamete of plants, just like sperm cells are in animals. Plants can be pollinated in one of three ways. The most common way is by wind, and this is the method that causes most problems for allergy sufferers. Wind-pollinated plants produce huge amounts of pollen that must stay in the air long enough to find a suitable female gamete for reproduction.
Pine pollen and cypress for that matter are more of a cosmetic problem than they are harmful. They are not major allergy causes because the pollen grains are relatively large. Therefore, they don’t stay suspended in the air as long as pollen grains of oaks and grasses. If they aren’t airborne as long, it is less likely they’ll find their way into nasal passages.
In general, wind-pollinated plants are the worst problems for two reasons. First, they usually produce huge amounts of pollen. This pollen also stays suspended in the air. Corn is wind pollinated and if you plant your garden with just a few long rows of corn, you might be greeted with many half-full ears come harvest time.
Wind is just one mechanism pollen is spread. Some is transferred by insects and other pollinating animals. This type of pollination makes it less likely for allergy sufferers to contact the pollen.
Plants that rely on pollinators usually have pollen that is somewhat sticky. This makes it stick to an insect’s body. Remember, an insect’s goal is not to pollinate flowers. The goal is to collect nectar and maybe some pollen too. Pollinating the flowers is just an added benefit for the plant.
Sticky pollen is not likely to wind up in one’s nose. That’s one reason I always shake my head every time I hear people blaming goldenrod for fall allergies when they should be blaming ragweed. Goldenrod flowers are very visible, but their pollen is sticky. Ragweed has less visible flowers, but the pollen is easily airborne and it’s what causes most people’s problems.
A third way plants are pollinated is by self-pollination. Generally, this method is not problematic to allergy sufferers. There’s no free pollen to wind up bothering anyone.
The method is also good for people who like to save their own seeds. If pollen never leaves the flower, we can be pretty sure what the resulting offspring will be. That’s why many old-timers save their heirloom tomato and bean seeds.
There’s a lot more to pollen than that nasty yellow stuff that accumulates on your car. We listen to many misconceptions and false accusations, but pollen is necessary for life.
Ted Manzer teaches agriculture at Northeastern High School.