Native to (or naturalized in) Oregon:
- Deciduous tree, 20-30 ft (6-9 m); dense, rounded headed. Thrones to 2.5 cm. Leaves alternate, simple, 2-6.5 cm long, 3-7 lobed, deeply incised, glossy green. Flowers white, 8-15 mm wide, with a single style (single ovary or stone, hence monogyna , i.e., with one pistil, the female element of a flower), in clusters (umbelate). Fruit oblong, 1 cm diam., red, with a single stone (seed).
- Sun, resistant to many diseases of Crataegus, e.g. rust. The many on the Oregon State Univ. campus possibly were rootstocks for scion types that died.
- Hardy to USDA Zone 4 Native to Europe, northern Africa, western Asia. Common in the English countryside as a roadside hedge. A very similar appearing species, but much rarer commerce, is C. ambigua, Russian Hawthorn.
- Invasive: Can be invasive since it is a prolific seed producer and can form dense thickets which exclude all understory plants. The Oregon Department of Agriculture lists C. monogyna as a potential “B” noxious weed. It very clearly degrades wildlife habitat in oak woodlands in our region forming very dense stands. It is also a nuisance in parks, fencerows, and fields. C. monogyna can hybridize with native hawthorn species such as the black hawthorn (C. douglasii) found in the west (Randall and Marinelli, 1996).
- Crataegus monogyna is naturalized in North America but is not common in American gardens; a few cultivars exist including a contorted version, Flexuosa.
- Oregon State Univ. campus: south side Ocean Admin. Building