''Crataegus persimilis'' is a species of

hawthorn Hawthorn or Hawthorns may refer to: Plants * '' Crataegus'' (hawthorn), a large genus of shrubs and trees in the family Rosaceae * ''Rhaphiolepis'' (hawthorn), a genus of about 15 species of evergreen shrubs and small trees in the family Rosace ...

, known by the common names plumleaf hawthorn and broad-leaved cockspur thorn, native to southern

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...

, Canada, and the US states of

New York New York most commonly refers to: * New York City, the most populous city in the United States, located in the state of New York * New York (state), a state in the northeastern United States New York may also refer to: Film and television * '' ...

Pennsylvania Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...

Ohio Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...

Kentucky Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia to ...

West Virginia West Virginia is a state in the Appalachian, Mid-Atlantic and Southeastern regions of the United States.The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States while the Bur ...

, and

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

. It is widely cultivated, particularly in Europe, as an ornamental. Its sporadic distribution in its natural range and certain of its morphological characters leads authorities to consider it a probable naturally occurring hybrid, with its most likely parents being ''

Crataegus succulenta ''Crataegus succulenta'' is a species of hawthorn known by the common names fleshy hawthorn, succulent hawthorn, and round-fruited cockspurthorn. It is "the most wide-ranging hawthorn in North America", native to much of southern Canada, and the U ...

'' (fleshy hawthorn) and ''

Crataegus crus-galli ''Crataegus crus-galli'' is a species of hawthorn known by the common names cockspur hawthorn and cockspur thorn. It is native to eastern North America from Ontario to Texas to Florida, and it is widely used in horticulture. It is thought to be th ...

'' (cockspur hawthorn). It is a

tetraploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains ...

. Some populations may be self-perpetuating. Its 'Prunifolia' cultivar has gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nort ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. History The Award of Garden Merit ...

, and is considered one of its top 5 trees for smaller gardens.

Description

Consistent with the hypothesis that ''C. persimilis'' is a relatively newly arisen hybrid species, there is quite a bit of variation in botanical characters between individuals. The variable traits include the shapes of the leaves, hairs and scales (or the lack thereof) on inflorescences, number of stamens, the color of the anthers, and pitting and other ornamentation (or lack thereof) of the

pyrena A pyrena or pyrene (commonly called a "pit" or "stone") is the fruitstone within a drupe or drupelet produced by the ossification of the endocarp or lining of the fruit. It consists of a hard endocarp tissue surrounding one or more seeds (also ...

s. The type specimen, collected along the

Genesee River The Genesee River is a tributary of Lake Ontario flowing northward through the Twin Tiers of Pennsylvania and New York in the United States. The river provided the original power for the Rochester area's 19th century mills and still provides h ...

near Rochester, New York, has the narrowest leaves, and the most stamens (10 to 20), of any described specimen. It also has pink anthers, sparsely pubescent corymbs, and deeply pitted pyrenas. The cultivated 'Prunifolia' has a much broader leaves as well as densely pubescent or nearly tomentose corymbs, and only ten pink anthers. ''C. persimilis'' are shrubs or trees, 5 to 6m tall and spreading with a dome-like growth form to about the same width. New twigs and stems are glabrous, with one year old bark a brownish purple, older growth is dull gray. The thorns found on twigs can be straight or recurved. Once the thorns have been on the tree for two years they are a shiny purplish black, and 4 to 7cm long. Typically older branches and the trunk do not have thorns. Its deciduous leaves are glabrous and coriaceous. The dark green leaf blades are more or less narrowly obovate to broadly elliptic or rhombic-elliptic, 4 to 5cm long, with serrate margins. The flowers are five-petaled and are white, with cream or pink anthers. The fruits are pomes, and bright scarlet when mature. They flower in May and fruit much later, in September or October. In autumn the leaves take on a striking range of colors from deep yellow to a fiery orange to scarlet and on to purple.

Uses

The ''C. persimilis'' cultivar 'Prunifolia' is used as a

street tree Urban forestry is the care and management of single trees and tree populations in urban settings for the purpose of improving the urban environment. Urban forestry involves both planning and management, including the programming of care and ...

, and is often used in gardens as an ornamental, especially for its spectacular autumn display. It is dense enough to use as a hedge or windbreak.

Pest and diseases

''C. persimilis'' is susceptible to fire blight (''

Erwinia amylovora Fire blight, also written fireblight, is a contagious disease affecting apples, pears, and some other members of the family Rosaceae. It is a serious concern to apple and pear producers. Under optimal conditions, it can destroy an entire orchard ...

'') but has some resistance. It is affected by hawthorn sawfly leaf miners ('' Profenusa canadensis''), but they seldom cause serious damage to healthy plants. It may also be afflicted by leaf spot (''

Diplocarpon mespili ''Diplocarpon mespili'' is a pathogenic fungus which causes quince leaf blight, a leaf disease affecting chiefly common quince. It occurs in wet summers, causing severe leaf spotting and early defoliation, also affecting fruit to a lesser exten ...

''), caterpillars, gall mites and aphids.

References

{{Taxonbar, from=Q17270668 persimilis Flora of Ontario Flora of the Northeastern United States Trees of the Northeastern United States Flora of Virginia Ornamental trees Plants described in 1903 Flora without expected TNC conservation status