ASK THE HORT AGENT
Question What is causing my beautiful Bradford pear trees to smell so bad?
Answer They must be blooming. Ah, the wonderful smell of spring. All Bradford pear trees stink. I mean literally. At least the flowers do.
Fragrance and color are properties plants use to attract pollinators (insects and animals that play a role in the plant's reproductive process). Many plants have customized their floral presentations to accommodate their pollinators. In other words, they offer incentive packages.
For example, most moths come out at night and white is the most visible color under moonlight. Therefore, plants which use moths as pollinators open at night and are usually white.
Many trees use the wind as a pollinator. Wind pollinated flowers are not showy. Instead, they are small, but produce much larger amounts of pollen for the wind to blow around. They are also the flowers that cause most of our allergy problems.
Most showy flowers are insect pollinated. Markings and colors on flower petals signal to insects how to approach and where to land, like lights on an airport runway. Bee pollinated flowers reflect ultraviolet light that is visible to insects but not to us.
Through fragrance, flowers can communicate with insects over long distances. Some male insects are tricked into transferring pollen by flowers that look and smell like females of their species. Flowers with foul odors attract carrion insects (mostly flies and beetles). Carrion insects feed on feces, rotting flesh and other decaying organic matter. They also lay their eggs in these smelly places. Egg-laying blowflies can locate a dead carcass or stinking flower within hours. They can smell the odor of a fresh, rotting carcass up to a mile away.
The fetid (stinking) flowers of Bradford pears are meant to smell like a rotting animal. This smell will attract blowfies. Bradfords use these insects to pollinate their flowers. Early bloomers, like Bradfords, may have better luck attracting flies than bees during a chilly spell. Evidently, they gave up on bees a long time ago. My guess is that nobody told you how stinking this pretty plant would be. Let me warn you ahead of time. If you buy a ginkgo tree, be sure and get a male. The female ginkgo also uses flies and beetles as pollinators. A female ginkgo makes a Bradford smell like a rose.
Keep your screen door shut so the flies won't get in the house. For more info about stinking flowers, visit http://www.floralibrary.com/flora/stinking/flowers If you have any questions, then call 910-893-7533 or email me at firstname.lastname@example.org
Many people donít even know what type of smell any flower has. They all smell the same when you are looking at them through a window. Beauty is in the eye of the beholder or the nose of the sniffer.
Gary L. Pierce
Horticulture Extension AgentHarnett County