Survives zone 6 through 9
Harvest calendar
Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.
Citrus polytrifolia (Poncirus polyandra) is an extremely rare, evergreen trifoliate citrus endemic to a single limestone area of Yunnan, China — extinct in the wild since 2023 and now surviving only in protected cultivation, where it is valued as a dwarfing, cold-hardy rootstock.
- Hardiness
- Zone 6–9
- Habit
- Shrub
- Edible part
- Fruit
- Ripens
- Winter (citrus)
- Mature size
- Evergreen shrub or small tree 2–4 m; containerable
- Light
- Full sun
- Soil pH
- 6.0–6.5 (slightly acid)
- Environment
- Garden origin
- Native range
- An extremely narrow endemic, historically known only from limestone habitats around Fumin County in Yunnan Province, China; wild populations are now considered extinct as of 2023, with all known material preserved in ex-situ, protected cultivation.
- Status
- Ornamental
- Years to fruit
- 2–3 yrs
- Growth speed
- Slow
- Spacing
- 250 cm (98 in) apart — about 6.3 m² (67 sq ft) per plant
- Leaf shape
- Evergreen — distinct from the deciduous Citrus trifoliata — with compound, trifoliate (three-leaflet) leaves documented as thicker and longer than those of Citrus trifoliata; stems are thorny.
- Root system
- Used in China as a dwarfing rootstock for other citrus, which is the practical fact about its roots: like its relative Citrus trifoliata it produces a compact, cold-hardy root system that restrains the scion. Its own root habit in the wild is barely documented — the species is extinct in the wild and survives only in conservation collections.
- Fruit description
- A small rounded citrus with a downy rind, ripening dull yellow, seedy and harshly sour with a resinous bitterness — like its trifoliate relatives it is not eaten fresh. The plant's importance is as a conservation subject and a rootstock, not as a fruit.
- Propagation
- Not commercially propagated in the way other citrus are — it survives only through ex-situ conservation collections. In China it has been used as a dwarfing rootstock for mandarin (Citrus reticulata), implying seed- or graft-based propagation similar to its close relative Citrus trifoliata, though standard nursery protocols for this species are not well documented in available literature.
- Pollination
- Most Citrus SELF-FERTILE (many parthenocarpic/seedless)
The edible parts listed above are a starting point, not a field guide. Identify a plant with certainty — ideally against a local authority — before eating any part of it, and read the full disclaimer. Spotted something wrong? Report it.
Growing guide
How it spreads. The opposite of a spreading or weedy species — an extremely rare, single-site endemic that does not sucker, with wild populations now extinct and surviving individuals confined to protected botanical cultivation.
Growing tips. Evergreen — unlike its deciduous relative Citrus trifoliata — with thicker, longer trifoliate leaflets and thorny stems; documented as cold-hardy and used in Chinese citrus breeding as a dwarfing rootstock for mandarin. Classified as a national second-class protected wild plant in China and considered extinct in the wild since 2023.
Grow journal
Sign in to keep a dated log of when you planted, bloomed and harvested this plant.