What if weeds gave the pollen forecast on the news instead of people? They’d probably use it to tell other weeds when the weather is good for making pollen!

Many plants spread their pollen in the wind. These plants are called “anemophilus”, which means “wind loving”. Their pollen grains are extra small to allow them to travel long distances in the air. Dry, windy days are perfect for wind-pollinated plants, so pollen counts tend be high on these days. Rain, on the other hand, can “wash” pollen out of the air and cause pollen levels to drop. Wind-pollinated plants are the cause of most seasonal allergies. Because the tiny pollen grains are floating in the air around us, they get into our nose and lungs when we breathe.

Not all plants spread pollen in the wind, though - some rely on insects. To attract insects, these plants usually have brightly colored flowers, and their pollen grains are large and sticky. The pollen gets picked up by bees and wasps and spread from flower to flower. Plants with big, colorful flowers are a lot less likely to cause allergies. Their giant, sticky pollen grains don’t hang in the air as long as tiny pollen grains do, so we are less likely to breathe them in.

Cartoon published in December 2023 Annals of Allergy, Asthma & Immunology: https://doi.org/10.1016/j.anai.2023.09.002