Sunflower Pollination Does Not Influence Vase Life

Flower growers have lots to worry about during the growing season: production issues such as the weather, pests and weeds, labor, marketing, taxes, etc. Here is one issue that we have just found not to be a problem: sunflower pollination.

Some flowers, notably snapdragons, some orchids and the potted plant cyclamen, shed their petals soon after the flower has been visited by a bee, or the pollen has been shaken onto the female part of the flower. Rather annoying for the consumer, or the cut flower grower, who is expecting at least a week of petal life.

What about sunflowers? Most cut flower varieties of this species have been selected to not produce pollen, because pollen makes unsightly stains on table cloths. But some varieties are pollen-producing, as are all those grown for snack food, birdseed and oil. And so it might be possible that in a mixed planting, bees will busily transfer pollen amongst them.

To find out if pollination matters with regard to flower longevity, we conducted a couple of tests in our high tunnel, either pollinating the flowers, or keeping them from being pollinated.

We then harvested the flowers, kept them for 5 or 7 days in water at room temperature, and then measured the petal retention force. The weaker the force holding the petals on the flower head, the closer they are to falling out, thereby ending the flower’s vase life.

We did the experiment in the 2011 and 2012 growing seasons, and in both, pollinated and unpollinated flowers had similar petal retention force after 5 and 7 days of flower storage. So don’t worry about the bees in your sunflower plantings; the flowers you harvest will last an equal length of time.

Photo Left: Pollenless Sunflower
Photo Right: Sunflower Producing Pollen

Chris Wien


Chris Wien is recently retired Professor of Horticulture at Cornell University. Contact him at [email protected]