The Odor of Hawthorn Trees

Trees dot our landscapes fulfilling one or more requirements. Providing shade, bearing fruits or outlining boundaries, each often has a drawback. That shade tree will have leaves to rake, the fruit will need to be picked or become a mess on the ground, and trees along property edges will need trimming. The hawthorn, a tall specimen tree, will become covered with beautiful spring blossoms that unfortunately have a most unpleasant odor.

The abundance of May flowers has earned the hawthorn the name mayblossom, maybush, or mayflower. When grown primarily as a hedge/boundary plant, due to its dense growth habit, the hawthorn is referred to as a hedgethorn. Additionally, hagedorn, haw and whitethorn are used interchangeably to mean the hawthorn tree. Regardless of the name, the pungent flower odor is unmistakable.

With a smell described as that of rotting or decomposing flesh, even the bees are reluctant to pollinate the flowers. Carrion beetles, insects that feast on or lay eggs in decaying matter, are erroneously attracted to the flowers believing it is decomposing flesh. As they move from flower to flower seeking their feast, they pollinate the flowers.

The common hawthorn has the misfortune of belonging to the hawthorn family and looking similar to the odoriferous hawthorns. With the offensive odor being the prominent feature of the hawthorn tree family, the common hawthorn is often wrongly frowned upon as an addition to the home landscape. However, the common hawthorn produces a very sweet-smelling flower.

When animal flesh begins to decompose it forms trimethylamine, a colorless gas with a strong, fishy, ammonialike odor. Research has found that the hawthorn flowers produce this same chemical. Traveling on air currents to reach pollinators near and far, this odor assures the pollination of the flowers, the setting of fruit and seed production, creating the next generation of hawthorn.