Native to (or naturalized in) Oregon:
- Deciduous shrub or small tree, 8-20 ft (2.4-6 m) tall and about 5-15 ft (1.5-4.5 m) wide, stems green, glabrous, with stout spines, 1-4 cm, and occasionally 7 cm long. Leaves alternate, compound, 3-foliate, terminal leaflet obovate to elliptic, 2.5-6 cm long, apex obtuse or emarginate, base wedge-shaped, dark green, lateral leaflets similar but smaller; petiole 8-20 mm long, often winged. Flowers white, solitary, fragrant, axillary, 5 petals, 3.5-5 cm across, 8-10 stamens, appear before or with leaves. Fruit globose, 3.5-5 cm across, green then yellow, very sour, contains numerous seeds.
- Sun, shelter from cold winds. Best in fertile well-drained soil. Frequently grown in a tub, against a sunny wall, or as a spiny hedge, it withstands shearing well. Because of the thorns, avoid planting near foot traffic areas. No serious pests or diseases.
- Hardy to USDA Zone 5 Native to northern China and Korea. Used as a dwarfing rootstock for citrus.
- A popular cultivar: 'Flying Dragon' - shrub or small tree, twisty stems and spines
- trifoliata: three leaves (leaflets)
- Portland, Oregon: Bishop's Close Elk Rock Garden.