Trifoliate orange

Profile

Family

Rutaceae

Habit

Shrub

Height

3.5 m

Spread

4 m

Growth

slow

Lifespan

35 years

First yield

after 5 years

Hardiness

zone 6–9

Shade tolerance

partial shade

Soil

Sand, Silt, Loam

Soil moisture

semi-dry – very moist

pH

5.5 – 6.5

Flowering & harvest

Times apply to the northern hemisphere in a temperate climate and shift with altitude and cultivar.

Uses

Edible: The fruit of the fruit tree can be cooked and has a bitter and sharp taste. It is suitable for making jam and refreshing drinks. Freshly picked fruits have little juice, but after storage for 2 weeks, about 20% juice rich in Vitamin C can be obtained. In America, yields of up to 14 kilograms of fruit per plant have been achieved. The fruit is 2-3 cm wide, with most of the mass coming from the skin. The fruit peel can be used as a flavoring. Young leaves can also be cooked.

Other uses: Used as an understock for citrus varieties, providing an additional cold resistance of 3°C. The plant is highly thorny, forming an impenetrable barrier or hedge, although not very dense. Highly tolerant to pruning, it is best trimmed in early summer shortly after flowering.

Growing

An easy-to-grow plant that thrives in ordinary garden soil, preferably well-draining but ideally in a fertile, light sandy soil in a sunny location. It grows and produces well in lightly shaded forests at the Cambridge Botanical Garden. These plants dislike soil disturbance near their roots and should either be well mulched to prevent weed growth or hand weeded. They also thrive in poor acidic and chalky soils. The bitter orange hybridizes with citrus species and could potentially be used in breeding programs to produce more robust forms of oranges, lemons, etc. It may also be valuable in imparting resistance to diseases, tolerance to poorer soils, and dwarfing characteristics. Flowers are formed on the previous year's wood. The entire plant, especially the flowers, is highly aromatic. A highly decorative plant that bears abundant fruit in Southwest England. A hedge shrub in Wisley in a semi-shaded location bears plentiful fruit most years. Another source suggests that warm autumn days are necessary for the plant to bear abundant fruit. Fertile seeds are produced after warm summers. The plants are relatively short-lived and deteriorate after about 25 years.

Propagation

Seeds are best sown immediately after ripening in a cold frame. Stored seeds should undergo cold stratification for 4 weeks and then be sown in a greenhouse in spring. Once the seedlings are large enough, they should be transplanted into individual pots and kept in the greenhouse for at least the first winter. In early summer, they can be planted in their final location. Cuttings from semi-hardwood can be taken in June/July in a frame.

Notable

Characteristics: prefers sandy and fertile soil; The utilization of the fruits is challenging due to their many seeds and little flesh; after 2 weeks of storage, they yield 20% more juice; a warm summer/autumn is necessary for the fruits to ripen; the bitter taste diminishes when mixed with other fruits.

Origin & habitat

East Asia - Central and South China, Korea.

Sandy heaths and moors, sometimes found in open forests and frequently near the coast. Strongly avoiding calcareous soils.

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