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.
- Crataegus monogyna is naturalized in North America but is not common in American gardens; a few cultivars exist including a contorted version, Flexuosa.
- Can be invasive since it is a prolific seed producer and can form dense thickets which exclude all understory plants. It can hybridize with native hawthorn species such as the black hawthorn (C. douglasii) found in the west (Randall and Marinelli, 1996).
- Oregon State Univ. campus: south side Ocean Admin. Building.