What is citrus?
A genus in the rue family, with a distinctive kind of fruit called a hesperidium.
fruits.im
Citrus, checked.
A sour family with glossy leaves, fragrant flowers, and a fruit that is not quite like any other berry. Sourced from the Royal Horticultural Society and Encyclopaedia Britannica, and written for people who want the wording to hold up.
Citrus is a genus of plants belonging to the rue family (Rutaceae), yielding pulpy fruits covered with fairly thick skins. Britannica The fruits are a type of modified berry known as a hesperidium, and the flesh is divided into segments packed with tiny juice-filled vesicles. Britannica The peel, or rind, of the fruits is leathery and studded with oil glands. Britannica
Citrus plants won't reliably survive winters outdoors, even in the warmest parts of the UK. RHS When grown in containers they can be kept in a greenhouse, conservatory or glazed porch over winter, then moved outdoors in summer into a sunny, sheltered spot. RHS
Growing in the UK
Citrus will not reliably survive winters outdoors here. Containers, glass, and a cool winter spell are the usual plan.
Types
Lemons, limes, oranges, kumquats, calamondins and more, with notes when names differ.
Lemons
A hybrid fruit, long grown around the Mediterranean, with a sharp juice rich in citric acid and vitamin C.
Limes
Several species and hybrids, from Persian and key limes to makrut and finger limes.
Kumquats
Small orange fruit with a sweet, edible rind. The scientific name depends on which good source you open.
A few things worth knowing
- The fruit ripens slowly, for up to a year, so plants often carry flowers and fruit at the same time. RHS
- Most commercially sold citrus plants are grafted to ensure they fruit at an early age. RHS Ungrafted plants may take up to ten years to fruit. RHS
- Yuzu is the most cold-resistant of all citrus fruits, capable of growing at high altitudes at temperatures just above freezing, and is most commonly associated with Japan and Japanese cuisine. Britannica
- Limes contain vitamin C (ascorbic acid) and were formerly used in the British navy to prevent scurvy, hence the nickname "limey," in Britannica's wording. Britannica
Citrus printables
Fact-checked PDFs in A4 and US Letter, sold as instant downloads from the ReallyByte store: our own drawings, a guide, and worksheets with answers. Prices in US dollars.
The Citrus Reference Guide
A fact-checked guide to what citrus is, how to grow it in the UK, and what lemons, limes and kumquats are, with our own drawings.
The Citrus Activity Pack
A quiz, myth-or-fact cards and worksheets with answers, following the sourced wording used on citrus.fruits.im.
Citrus Fruits: Lemons, Limes, Kumquats and Calamondins
A short sourced companion to four citrus fruits, including notes where good sources disagree on names or tree size.
The Complete Citrus Printables Bundle
All three packs, A4 and US Letter, at a bundle price.