Poncirus trifoliata – Hardy Orange

General Information: The species Poncirus trifoliata is a small, very spiny tree, of interest for being a hardy, deciduous near-relative of Citrus fruits. Because the twigs and spines are green, the plant appears green even when leafless. Produces attractive, fragrant, white flowers in spring, which develop by fall into yellow fruits resembling small Oranges. These sour fruits are often considered inedible, however there are plenty of recipes available that state otherwise. The straight species is also used commercially as a rootstock on which to graft other non-dwarfed Citrus fruits. Considered cold hardy to about -15° F, its range of cultivation can be extended into Zone 5 if it is planted in a sheltered location and perhaps given some extra protection from the cold.

Edible Qualities: Michael Dirr, in Manual of Woody Landscape Plants, comments that “Ripe fruits set aside for several weeks become juicy and develop a sprightly, slightly acid flavor. Serves as a substitute for lemon, pulp can be made into marmalade, and peel can be candied. After removing the numerous seeds there is not a whole lot of pulp left over.” The fruits can also be dehydrated or freeze-dried and pulverized for use as a condiment. Fresh or pulverized fruits are useful as a marinade for various meat dishes.

Cultivation Details: This plant is Self-fertile. Only one is required for fruit set. ‘Flying Dragon’ is a selection identified by its strongly recurved, claw-like thorns. The interesting ornamental growth habit is particularly evident when the plant is leafless. ‘Flying Dragon’ is highly prized in the Orient, having been cultivated for centuries as a medicine. ‘Flying Dragon’ is also a dwarf cultivar, growing to a maximum height of 6′ (smaller in containers). Commercially used as a dwarfing rootstock for other Citrus plants. A unique, rarely used tree suitable for bonsai training. Ideal in cold climates for outdoor planting, as the seeds are far less likely to germinate and any immature plants that do crop up are easily recognized and removed. Consider this species for container planting or bonsai training in warmer climates (Zones 8 and up). Widely planted in the South during the Civil War around forts as a biological form of barbed wire, these plants form an impenetrable barrier if they are allowed to! As a result of these plantings, however, their populations in the Southern States have gone out of control. We recommend growers south of the 40th parallel exercise judgment when discarding seeds and unusable fruit. Eating is a preferred means of control of this plant.

Growing Requirements: Plant in full to part sun. In colder climates, plants require some protection from winter winds. Prefers moist, well-drained soils. Tolerant of most soil types and conditions. Tolerates very acidic as well as very alkaline soils.

Fun Facts: The genus Poncirus was separated from Citrus in the 1940’s, however recent DNA analysis has placed this species back in the genus Citrus. Many botanical sources list the currently accepted name of this species as Citrus trifoliata, however the generic name Poncirus is still common in the nursery trade.