The hawthorn plant (Crataegus) is a small tree or thorny shrub found across temperate regions of the Northern Hemisphere. Prized for its dense foliage, it is often used in hedgerows and displays profuse small, white or pinkish blossoms in spring. This flowering period gives the plant its alternative name, the May-tree, as it traditionally blooms around the start of that month. Despite its ornamental value, the hawthorn possesses one feature that often elicits a strong, polarized reaction: the potent and unusual scent of its flowers.
The Distinctive Aroma
The scent of hawthorn blossom is often described as a complex paradox, possessing notes that are both sweet and repulsive. When the small, five-petaled flowers are in full bloom, they release a heavy fragrance with a sickly-sweet undertone, sometimes reminiscent of honey or bitter almond. This sweetness is quickly overshadowed by a sharp, metallic odor that many find unpleasant.
The most common descriptors for the hawthorn’s fragrance are fishy, musky, or strongly suggestive of decay. People frequently report a resemblance to the smell of decomposition or spoiled meat. This powerful odor is most noticeable when the air is warm and still, allowing the volatile compounds to concentrate and waft from the dense clusters of flowers.
The Chemical Explanation
The scientific reason for the hawthorn’s peculiar smell lies in a specific volatile organic compound: Trimethylamine (TMA). This simple organic compound is a breakdown product of organic matter, explaining the strong olfactory link to decay. TMA is one of the first chemicals released as animal tissue begins to decompose, which is why the flower scent mimics the odor of dead fish or a corpse.
The hawthorn produces this compound for a clear biological purpose: its reproductive cycle. While most flowering plants use sweet aromas to attract generalist pollinators like bees, the hawthorn utilizes TMA to specifically attract carrion insects, such as flies and certain beetles. These insects are drawn to the scent of rotting flesh and inadvertently transfer pollen between the flowers, ensuring successful propagation.
Cultural and Historical Context
The unique, death-like odor profoundly influenced the hawthorn’s standing in European folklore for centuries. Because the smell resembled the stench of decomposition, the plant became historically associated with bad fortune and death. This belief created a powerful superstition: bringing hawthorn flowers into a home was thought to invite illness or fatality upon the occupants.
During periods of widespread disease, such as the Great Plague, this association intensified, as the flower’s aroma was said to recall the smell of the deathbed. This historical context explains why the hawthorn was both revered in the landscape and feared indoors, despite its springtime beauty.
Species Variation and Intensity
The intensity of the hawthorn’s fragrance is not uniform across the entire genus, which contains hundreds of species and cultivars. The concentration of Trimethylamine can vary significantly depending on the specific Crataegus species, as well as environmental factors like local climate and soil composition. This variation leads to different sensory experiences.
For example, the common hawthorn (Crataegus monogyna) is recognized for its sweet yet musky odor. In contrast, the Midland hawthorn (Crataegus laevigata) is sometimes noted for having a particularly strong odor of rotting flesh. Many cultivated varieties, such as those bred for pink or red flowers, have been selected for a lack of fragrance or a much milder scent profile.