Orange, Trifoliate

Trifoliate Orange, Poncirus trifoliata (syn. Citrus trifoliata), is a member of the family Rutaceae, closely related to Citrus, and sometimes included in that genus, being sufficiently closely related to allow it to be used as a rootstock for Citrus. It differs from Citrus in having deciduous, compound leaves, and pubescent (downy) fruit. The plant is fairly hardy (USDA zone 5) and will tolerate moderate frost and snow, making a large shrub or small tree 13–25 feet tall.

It is native to northern China and Korea, and is also known as the Chinese Bitter Orange.

Poncirus trifoliata is recognizable by the large 1.2–2.0 inch thorns on the shoots and STEMS, and its deciduous LEAVES with three (or rarely, five) leaflets, typically with the middle leaflet 1.2–2.0 in long, and the two side leaflets 0.8–1.2 in long. As with true citrus, the leaves give off a spicy smell when crushed.

The FLOWERS are white, with pink stamens, 3–5 cm in diameter, solitary in leaf axils, white, 5-parted, aromatic. They are larger than those of true citrus but otherwise closely resembling them, except that the scent is much less pronounced than with true citrus.

The FRUITS are green, ripening to yellow and 1.2–1.6 inches in diameter, resembling a small orange, but with a fine downy surface. They are very bitter, are not edible fresh, but can be processed into palatable forms.

The BARK is relatively smooth, mostly brown to green-brown but is striped with green and is protected by large alternating thorns that grow larger as the plant ages. Poncirus trifoliata can be trained/pruned into an impenetrable thicket- type hedge that blooms and produces fruit.

WILDLIFE: The flowers attract all manner of insects to assist in pollination while the fruit is fair game for many small mammals.