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Shrub or tree to 12 m. Branchlets glabrous; thorns stout, to 1.4 cm long. Buds 0.1–0.5 cm long. Leaves deciduous, leathery, 2.3–5.7 × 2.9–5.4 cm, roughly triangular, upper surface dark or bright green and glabrous to villous, lower surface greyish green and villous along the veins and in the vein axils, two to four secondary veins on each side of the midrib, margin with two to four lobes on each side of the midrib, lobe margins dentate particularly towards the apex, apex acute to rounded; petiole 0.6–3.5 cm long; stipules 0.4–1.8 cm long, entire or serrate. Inflorescence corymbose, rather lax, 4–5 cm long with 12–20 flowers. Flowers white; hypanthium glabrous, 0.2–0.4 cm long, sepals triangular and persistent, petals 0.5–0.7 cm long, stamens 18–20 with purple anthers. Fruit 0.8–1.4 × 0.7–1.3 cm, dark red or blackish purple with persistent reflexed sepals at the crown, flesh yellowish, seeds one to two (to three). Flowering May to June, fruiting July to October (wild plants). Christensen 1992. Distribution ARMENIA; IRAN; RUSSIAN FEDERATION; TURKEY; UKRAINE: Crimea. Habitat Woodland on rocky slopes, riversides, in gullies and on steppe, often over calcareous rock; between 0 and 2700 m asl. USDA Hardiness Zone 4–5. Conservation status Not evaluated. Illustration Christensen 1992.
Crataegus ambigua is widely recommended by horticultural websites in North America as a useful landscaping plant, with numerous good qualities, but curiously it is omitted by Phipps et al. (2003). Its environmental tolerances are its chief asset – not only being extremely hardy, but also tolerating drought conditions and difficult sites (for example, where the soil is compacted) (Sedbrook 2007). As a tree it is rather similar in appearance to C. monogyna, with somewhat contorted limbs, but it has attractive yellowish bark that exfoliates, contributing to its winter interest. The abundantly produced fruits are dark purplish red. It is said to be resistant to Gymnosporangium juniperi-virginianae, Cedar-apple Rust. It is rare in European collections, but there is a shrubby 4 m specimen at Kew, received from Ashkhabad Botanical Garden in 1936, and a 7 m tree was measured at the Hillier Gardens in 2003 (Sir Harold Hillier Gardens database).