GARDENING: Pollen season is beginning

Credit: Contributed

Credit: Contributed

This week, I heard an interesting piece on TV in which someone alluded to the fact that “flowers like tulips and daffodils don’t cause allergies,” but trees like oaks and maples do.

This caught my ear because oaks and maples do have flowers, and yes, they do cause allergies.

When people make broad sweeping statements like this, it makes me crazy. So many people don’t understand plants, and some even have “plant blindness.”

That is one of the reasons I love my job working for The Ohio State University. I have the responsibility of teaching research-based science involving the plant world (and things that are attached to it).

I want to inspire people to learn more about plants and I hope that through this column, you have learned more about plants than you ever knew.

Back to my point in the beginning and a little review of plant botany. Vascular plants are divided into two groups, angiosperms, and gymnosperms.

Gymnosperms produce seeds that lack an outer fruit, like a pine cone. Pollen is involved. These plants have male and female cones; the female cones receive the pollen grains from the female.

Anyone having pine trees in the landscape may have seen puffs of yellow when touching the branches in the spring. The puffs are pollen released from the male pollen cones. Male cones look different than the female cones; these are the brown cones that are quite visible.

Angiosperms on the other hand, are flowering plants that develop seeds that are contained in a fruit. Think tomato, pepper, orange, maple, sunflowers, etc.

Showy flowers have a purpose - to attract pollinators. Most of the time, the not so showy flowers are wind-pollinated since they aren’t as attractive to pollinators. Not all of them are like this, but many of them.

Both groups of plants have flowers that contain pollen. Pollen and consequently reproduction ensure that the species continues. If there were no pollination, the species would become extinct.

Trees such as oaks and maples have flowers, we just don’t usually see them or pay attention to them. For instance, red and silver maples are blooming right now in the Miami Valley.

It goes a little deeper even when we start talking about perfect and imperfect flowers. Perfect flowers have both male and female parts contained in one. Imperfect only have the male or female part. Therefore, another flower is needed for pollination.

Credit: Contributed

Credit: Contributed

Hollies for instance have male and female flowers. On top of all the above, they have male and female flowers on different plants. Therefore, you need a male and a female plant to get the beautiful red berries on the female.

These terms are monoecious meaning a plant with male and female (imperfect) flowers on the same plant and dioecious refers to a plant with male flowers on one plant and female flowers on two plants.

Confusing, yes; I suppose that is why some people make broad brushstroke statements. At any rate, maple flowers are producing a lot of pollen causing headaches, literally.

Pamela Corle-Bennett is the state master gardener volunteer coordinator and horticulture educator for Ohio State University Extension. Contact her by email at

About the Author