Photo: Phuong Tran — CC BY 2.0 · source
Survives zone 8 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 japonica (kumquat) is a compact evergreen citrus grown for its small, sweet-skinned fruit, which — unlike almost every other citrus — is eaten whole, peel and all.
- Hardiness
- Zone 8–9
- Habit
- Shrub
- Edible part
- Fruit
- Ripens
- Winter (citrus)
- Mature size
- Evergreen shrub or small tree 2–4.5 m; excellent in containers, and the classic urban citrus
- Light
- Full sun
- Soil pH
- 6.0–6.5 (slightly acid)
- Environment
- Subtropical
- Native range
- Native to southern and eastern China, where it grows in warm, humid forest margins; long cultivated across East Asia and now grown as an ornamental and fruit crop worldwide.
- Status
- Cultivated
- Years to fruit
- 2–3 yrs
- Growth speed
- Generally slow and compact-growing, naturally forming a dense, dwarf-like canopy rather than rangy growth.
- Spacing
- 165 cm (65 in) apart — about 2.7 m² (29 sq ft) per plant
- Leaf shape
- Evergreen, simple (unifoliate) leaves, alternate, ovate-elliptic to lanceolate with entire margins, roughly 4–11 cm long — not trifoliate, unlike Citrus trifoliata and Citrus polytrifolia.
- Root system
- Own-root (seed- or cutting-grown) kumquats develop notably weak, poorly performing root systems, which is why commercial trees are almost always grafted onto a sturdier rootstock.
- Fruit description
- Bright orange, oval-to-round fruit about 2.5–5 cm long with a thin, smooth, sweet peel and a juicy, tangy-tart interior. Unusually among citrus, the whole fruit — skin included — is eaten out of hand, candied, or preserved in marmalade.
- Propagation
- Almost always grown from grafted stock rather than from seed or cuttings — own-root kumquats develop weak root systems and rarely thrive, so named cultivars are typically budded onto a more vigorous citrus rootstock.
- 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
Fertilizing. Prefers a moderately heavy loam with generous compost and sand added, in full sun, at pH 5–6; benefits from regular light feeding with a nitrogen-rich, citrus-formulated fertilizer during the growing season, since container-grown plants especially are prone to nutrient deficiency.
How it spreads. A compact, single-trunked tree with a dense, rounded canopy that is generally thornless to lightly spined; it does not sucker or spread — its bushy look comes from branching habit, not root spread.
Growing tips. Hardy to roughly USDA zones 8–9; notably, kumquats cease active growth once temperatures drop below about 13°C and, when dormant, can tolerate brief dips to around -5°C — somewhat hardier in practice than many other evergreen citrus, though far less cold-tolerant than Citrus trifoliata or yuzu. Species-specific citrus greening (HLB) data is sparse in the literature, though kumquats are grown commercially in HLB-affected regions and are not considered immune.
Grow journal
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