Hawthorn, English — Hawthorn (Crataegus) is a large genus of shrubs and trees in the family Rosaceae, native to temperate regions of the Northern Hemisphere in Europe, Asia and North America. The name hawthorn was originally applied to the species native to northern Europe, especially the Common Hawthorn C. monogyna, and the unmodified name is often so used in Britain and Ireland. However the name is now also applied to the entire genus, and also to the related Asian genus Rhaphiolepis.
They are shrubs and small trees growing to 5-15 m tall, characterized by their small pome fruit and thorny branches. The bark is smooth grey in young individuals, developing shallow longitudinal fissures with narrow ridges in older trees. The fruits are sometimes known as “haws”, from which the name derived. The thorns grow from branches, and are typically 1-3 cm long. The leaves grow spirally arranged on long shoots, and in clusters on spur shoots on the branches or twigs. The leaves themselves have lobed or serrate margins and are somewhat variable shape.
The number of species in the genus depends on taxonomic interpretation, with numerous apomictic microspecies; some botanists recognise a thousand or more species, while others reduce the number to 200 or fewer.
Hawthorns provide food and shelter for many species of birds and mammals, and the flowers are important for many nectar-feeding insects. Hawthorns are also used as food plants by the larvae of a large number Lepidoptera species.
Many species and hybrids are used as ornamental and street trees. The Common Hawthorn is extensively used in Europe as a hedge plant. Several cultivars of the Midland Hawthorn C. laevigata have been selected for their pink or red flowers. Hawthorns are among the trees most recommended for water-conservation landscapes.
The dried fruits of Crataegus pinnatifida are used in naturopathic medicine and traditional Chinese medicine, primarily as a digestive aid. A closely related species, Crataegus cuneata (Japanese Hawthorn, called sanzashi in Japanese) is used in a similar manner. Other species (especially Crataegus laevigata) are used in Western herbal medicine, where the plant is believed to strengthen cardiovascular function. In recent years, this use has been noted and adopted by Chinese herbalists as well. Hawthorn is also used as an aid to lower blood pressure, and treat some heart related diseases.