hawthorns

There are about 230 species of hawthorn worldwide, at least 152 in North America north of Mexico, and 12 species in Minnesota. Two additional species, historically native to Minnesota, have not been seen in the state for more than 100 years and are now presumed extirpated.

Hawthorns need full sun to moderate shade, only a moderate amount of water, and little competition from other shrubs and trees. The seeds take two years to germinate. The plants grow slowly and are long-lived. They flower in the spring while the leaves are expanding, and produce abundant fruits in the fall. The seeds are dispersed by mammals and birds.

Hawthorns are often an important part of an ecological community. They provide shelter for birds and mammals, are hosts for many species of moths and butterflies, and provide food in winter for wildlife, especially thrushes and waxwings. Their numbers have been decreasing in the state due to several factors, including conversion of land to agriculture, fire suppression, competition from eastern redcedar, and susceptibility to cedar apple rust, which reduces the number of flowers and produces deformed fruits with aborted seeds.

Hawthorns are small trees or shrubs. The trunks are sometimes armed with simple or compound thorns. The branches often have straight or curved thorns. The leaves are deciduous and alternate, They are scattered on the branches and crowded at the tips of short branchlets. Leaf margins have gland-tipped teeth. The inflorescence is small, dome-shaped to flat-topped, branched clusters (panicles) of several to many flowers at the end of short branchlets. The flowers have 5 sepals, 5 petals, 10 to 20 stamens, and 2 to 5 styles. The fruit (pome) is 2 to 5 stones surrounded by thick flesh.

Where two or more hawthorn species occur in close proximity they often hybridize, producing plants with intermediate characteristics and making identification to the species level difficult.

Sources

2, 3, 4, 5, 7, 8, 24, 28, 29, 30.

On the side of my driveway

thorns on a hawthorn tree near MN/IA border

Location: Kanabec County, MN

On the side of my driveway

Location: Wright County

Location: Kellogg Weaver Dunes SNA, South Unit

Location: near MN/IA border

thorns on a hawthorn tree