Sometimes an attractive-looking or useful tree can lose its luster when the time comes for pollen production. Typically, pollen is considered sweet-smelling and mild, but this is not always the case. Throughout the year, many trees produce strange or foul-smelling pollen odors that might not smell nice to humans, but are irresistible to flies and other insects.
Function of Pollen Odor
The smell of some tree pollen is unpleasant enough to compel people to keep their door shut during blooming times. But pollen odor serves an essential function. The scents of pollen and flowers are designed to send signals to insects, which are responsible for plant reproduction. Certain odors either attract or deter insects from pollinating it. Sweet-smelling pollen is present on a number of trees, including the Hala tree, and tends to attract bees. Others emit foul smells that are designed to attract flies and other insects for pollination.
Early Summer Pollen Odor
Strong pollen smells in early summer may be attributed to the Chinese chestnut tree. Its pollen can emit a smell that is very bothersome to many people. It might be best to avoid planting the tree in crowded areas. Identify this tree by its low-hanging, wide-branching habit that can reach as far as 50 feet wide and tall. It works well as an orchard tree but is not fitting as a shade tree. It is smaller than the native American chestnut and often serves as a replacement for it.
Fall Pollen Odor
If you notice a strong pollen smell roughly between September and November, the carob tree may be to blame. The carob tree is considered to have pollen that strongly resembles human semen in smell. The smell works to attract insects, which are responsible for pollination. The tree is evergreen and can reach up to 30 feet high. It has sturdy branches and rough bark, as well as leaves that are oval-shaped. The flowers are red with a green tint. Blooming time is normally in autumn, but can vary.
Spring Pollen Odor
In spring, pollen odor from species such as the Bradford pear give the air an unpleasant aroma. Bradford pear is a very popular ornamental tree with beautiful flowers in springtime. It's easy to grow, being drought-resistant, tolerant of poor soils and free from diseases, but it has a strong, fishy smell that is unpleasant to many people. Many people report that the pollen has an odor similar to that of rotten fish. The tree is attractive, showy and hard to kill. Another drawback of this tree is that the branches are prone to breaking at maturity, which is about 15 to 30 years, so it is short-lived.