Kumquat Citrus japonica
Kumquat (Citrus japonica) is an evergreen perennial fruit plant in the Rutaceae family, native to Southern China. It grows 1.5–3 m (4.9–10 ft) tall and 1.5–2.5 m (4.9–8.2 ft) wide, wants full sun and moderate water, and is hardy to about -8 °C (18 °F). Space plants about 2.5 m (8.2 ft) apart.
Plan Kumquat in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Kumquat at a glance
| Type | Perennial fruit plant, evergreen |
|---|---|
| Family | Rutaceae |
| Mature height | 1.5–3 m (4.9–10 ft) |
| Mature spread | 1.5–2.5 m (4.9–8.2 ft) |
| Spacing | 2.5 m (8.2 ft) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance low |
| Soil pH | 6–7.5 |
| Cold hardiness | About -8 °C (18 °F) once established (roughly USDA zone 8) |
| Heat stress | Likely above about 38 °C (100 °F) |
| Flowering | from about May for 3–6 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | High |
| Edible | Yes: whole fruit (peel and flesh) |
| Native to | Southern China |
| Common in gardens of | 🇨🇳 China, 🇯🇵 Japan |
Is Kumquat toxic?
- People: not known to be toxic
- Cats: moderately toxic
- Dogs: mildly toxic
- Parts: leaves, peel, seeds
Essential oils and psoralens in the peel, leaves and seeds can cause vomiting, drooling or depression in pets; the flesh is safe for people.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Kumquat
No well-documented helpful pairing. Group it with plants that like full sun and moderate water.
Keep apart or take care
- caution With Sweet orange: Asian citrus psyllid spreads huanglongbing (citrus greening) between citrus and relatives such as orange jasmine (Murraya). Keep new citrus away from infected or neglected hosts. Evidence B
Shared pests and diseases
- Citrus greening (HLB): Spread by the Asian citrus psyllid, which also breeds on curry leaf (Murraya). Evidence B
- Xylella fastidiosa: Insect-spread bacterium (EU quarantine pest) hitting olive, lavender, rosemary, oleander, Prunus and citrus. Evidence B
Questions about Kumquat
- How far apart should I plant Kumquat?
- About 2.5 m (8.2 ft) apart, centre to centre. A mature plant spreads 1.5–2.5 m (4.9–8.2 ft).
- Does Kumquat need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Kumquat need?
- Moderate water. Drought tolerance is low and waterlogging tolerance low.
- How cold-hardy is Kumquat?
- It tolerates about -8 °C (18 °F) once established, roughly USDA zone 8.
- When does Kumquat flower?
- From about May for 3–6 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Kumquat poisonous to cats and dogs?
- For cats it is moderately toxic; for dogs mildly toxic; for people not known to be toxic. Essential oils and psoralens in the peel, leaves and seeds can cause vomiting, drooling or depression in pets; the flesh is safe for people.
- What grows well with Kumquat?
- There is no well-documented companion pairing for Kumquat. Group it with plants that like the same sun (full sun) and water (moderate).
Sources and evidence
Evidence grade C (C: plausible, mixed evidence).
- UF/IFAS Extension tropical and subtropical fruit and landscape publications, University of Florida
- University extension gardening guides (general), Various land-grant university extensions
- ASPCA Toxic and Non-Toxic Plant List, ASPCA
Notes and assumptions
- Includes Nagami and Meiwa types (formerly Fortunella). The hardiest edible citrus when dormant (about −8 °C); blooms late, in summer. Slow growing, suits containers.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Lemon tree (dwarf) Citrus limon
- Curry tree Murraya koenigii
- Kaffir lime Citrus hystrix
- Common rue Ruta graveolens
- Sweet orange Citrus x sinensis
- Mandarin orange Citrus reticulata
- Persian lime Citrus x latifolia
- Key lime Citrus x aurantiifolia