Sex, Drugs And Plant Biology: Why Everything Is Covered In Green Gunk

Apr 7, 2015

Every spring clouds of green pollen descend on Austin, bringing misery to allergy-suffering public radio reporters like me and frustrating drivers like DeAunderia Bowens.

"You know I just got my car washed and literally got up the next morning and my car was covered with this green stuff!" she said on her way to work. "If I had a green car, it would be all right, but clearly it's not working on a grey vehicle.”

This time of year the stuff is oak pollen, but why does it get everywhere? The answer might make you look at trees a little differently.

It turns out we are surrounded by tree sex.

UT Biology Professor Norma Fowler knows a thing or two about tree sex.
Credit Mose Buchele/KUT News

"Plants have sex, they really do,” University of Texas Biology Professor Norma Fowler tells me at her office.

Here's how it works: When humans want to reproduce, they choose a partner. Trees are a little less discriminating. Oak trees have both male flowers and female flowers.  The male flowers are little strands called “catkins.” You see them in piles on the ground these days.  

"What [the catkins] do is they just throw the pollen, which is what the male flowers produce. Throw it out into the wind," says Fowler. "The female flowers are very small, they're like little brushes, and they just strain that pollen out of the wind. That’s plant sex.”

Oak pollen is causing allergies to flare up in Austin.
Credit Mose Buchele/KUT News

It is also why the pollen gets everywhere.  Trees need to produce tons of pollen if they're going to have any chance of, somehow, reaching the female flowers. The strategy works well for the trees, but not for people with allergies.

"An awful lot of the pollen doesn't land on the females," says Fowler. "It lands on the sidewalks, it lands on the cars, it gets in our noses.” 

She pauses to wipe her nose. 

"Sorry, it’s a bad day today," she says.  “I’m properly drugged up with over-the-counter drugs like everybody else in Austin today."

Full disclosure: I am, too.