Mandarin

Mandarin: how do you recognise it?

Habit

Small evergreen tree; as a container plant 1.5–2.5 m tall and about 1.5 m wide, with a rounded crown.

Leaves

Lance-shaped to oval, 4–8 cm, glossy dark green; aromatic when crushed.

Flowers

White, star-shaped flowers with five thick petals in April–June; strongly and sweetly scented.

Fruit

Flattened, 5–8 cm, with a thin, easy-peel skin. It ripens slowly and only turns orange in winter.

Thorns

Some plants have short, sharp thorns on the shoots.

Flowering: April–June · Harvest and fruit: December–February · Plants: April–May · Pruning: March

Why grow it?

• Glossy evergreen leaves: an ornamental plant for the patio or conservatory all year round.
• The white flowers have a lovely sweet scent in April–June.
• Flowers and ripening fruit often hang on the plant at the same time.
• Your own fruit to pick in winter, although the crop from a container plant stays modest.
• Most mandarins set fruit even without a second plant.

Mandarin: where does it grow best?

• Summer: outdoors in the sunniest sheltered spot, for example against a south-facing wall.
• Winter: cool and bright indoors at 5–12 °C, for example in an unheated conservatory or a light, frost-free room.
• Open, well-drained compost, slightly acid to neutral: citrus compost or potting compost mixed with sand or perlite.
• Evenly moist: the top of the root ball may dry out between waterings, but the root ball must never dry out completely.

Light

Sun

Soil type

Sand or loam

Acidity

Acid or neutral

Moisture

Normal

Size

2.5 m tall, 1.5 m wide

Hardiness

Half hardy (to -3 °C): protect it in harsh winters

Goes well with

• Olive: Another Mediterranean container plant with the same summer sun and cool overwintering.
• Bay: An evergreen container plant as a calm backdrop on the patio.
• Lavender: A scented pot for the same sunny spot in summer.
• Star jasmine: Scented white flowers in summer, just like the mandarin.

Mandarin: when and how to plant it?

Plant in April–May.

1. Repot in April–May, before the plant goes outside, and only when the roots fill the pot.
2. Choose a pot 3–5 cm wider than the old one, with a drainage hole; terracotta lets the compost breathe.
3. Put a layer of gravel or clay pebbles in the bottom for good drainage.
4. Use citrus compost, or ordinary potting compost with a third of coarse sand or perlite.
5. Set the plant at the same depth as before: the graft union stays above the compost.
6. Water with rainwater until it runs out of the bottom and let the pot drain well.

Care

Watering

Water when the top 2–3 cm feel dry, preferably with rainwater: hard tap water turns the leaves yellow. Never leave water standing in the saucer.

Feeding

From March to September, citrus feed or a feed for container plants every two weeks. No feeding in winter.

Overwintering

Bring it in in October, before the first frosty nights, and only put it out again after mid-May, first for a few days in partial shade.

Pollinating

Indoors you can pollinate the flowers with a soft brush for a better fruit set.

Harvesting

Pick the fruit when it is fully orange and gives slightly, usually from December to February. Delicious fresh, in fruit salad, as juice or with the grated zest in baking.

Tip: Put your mandarin in the sunniest spot outside in summer and overwinter it cool and bright, at 5–12 °C. Water with rainwater: the leaves stay dark green and the fruit colours a lovely orange in winter.

Mandarin: when to prune it?

Pruning months: March.

When: In March, before new growth starts, while the plant is still indoors. After that, only light trimming.

How:

• Remove dead, weak and inward-growing shoots.
• Shorten shoots that are too long to just above a leaf, for a compact, rounded crown.
• Remove shoots growing from the rootstock below the graft union; they often have different leaves and larger thorns.
• Do not prune too hard: you will get lots of leaves and few flowers.

Caution: Wear gloves when handling thorny plants.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Cuttings

In July–August take semi-ripe cuttings of 10–15 cm and root them under plastic at 20–25 °C. It does not always work and takes several months.

Seed

A pip easily grows into a little plant, but it takes many years before it flowers and fruits. Fun to try; for fruit it is better to buy a grafted plant.

Mandarin: how does it get through the winter?

Hardy to −3 °C: protect in harsh winters.

• Not hardy: it tolerates at most a brief −3 °C. In Belgium it overwinters indoors.
• A bright, cool spot at 5–12 °C is ideal. In a warm, dark room it drops its leaves.
• Water sparingly in winter: keep the root ball just moist.
• Check regularly for scale insects and mealybugs, which spread quickly indoors in winter.

Diseases and pests

• Yellow leaves: Yellow leaves with green veins point to iron deficiency, often caused by hard water. Water with rainwater and use citrus feed.
• Leaf drop: Sudden heavy leaf loss after bringing it indoors, caused by too little light, draughts or overwatering. Keep it cool and bright and water less.
• Scale and mealybug: Brown scales or white fluff on stems and leaves, and sticky leaves with black sooty mould. Wipe them off with a cloth dipped in lukewarm soapy water.
• Red spider mite: Finely mottled, dull leaves and webbing in dry, warm air. Mist the leaves regularly and move the plant somewhere cooler.
• Fruit drop: Young fruitlets drop after a dry spell or when there are too many. Keep the root ball evenly moist; some always drop naturally.

Through the year

• January: Cool and bright indoors. Little water. Harvest fruit.
• February: Harvest fruit. Watch for scale insects.
• March: Prune. Start feeding.
• April: Repot if needed. Flowering begins.
• May: Put outside after mid-May, first in partial shade. Flowering.
• June: Flowers and young fruitlets. Feed every two weeks.
• July: Water regularly. Take cuttings.
• August: Water and feed. Take cuttings.
• September: Last feed.
• October: Bring indoors before the first frost.
• November: Overwinter cool and bright. Little water.
• December: The fruit turns orange. First harvest.

Edible and useful

Fruit (December–February)

A mandarin in a pot flowers in April–June; the fruits ripen slowly and only turn orange in winter, from December to February. Pick them when they are fully orange and give slightly, and taste one first: a mandarin does not get any sweeter after picking. They are lovely fresh, in fruit salad or a winter salad with chicory, as juice, and the grated zest goes into cakes and bakes. Dried peel gives tea, stews and biscuits a warm citrus scent. Only use the peel of your own untreated fruit.

Storing

Unpeeled mandarins keep for a week somewhere cool, and two to three weeks in the fridge. Grate the zest before you peel the fruit and freeze it in a bag. Dried peel keeps for a year in a closed jar.

Caution: Only use the peel of fruit from your own plant that has not been sprayed: only eat fruit from a newly bought plant after a year, once new fruits have grown at home, as garden-centre plants are often treated with products not approved for food. The mandarin is not hardy: overwinter it frost-free, light and cool at 5–12 °C, and harvest indoors or in a greenhouse. Spit out the pips.

Eating and using is at your own risk: see the terms of use.

Recipes

• Chicory salad with mandarin and walnuts (Dish · 4 people · 15 min)
• Dried mandarin peel (Dried · ± 30 g · 15 min + 3 to 7 days drying)

Did you know?

• Citrus fruit does not ripen after picking: a mandarin does not get any sweeter once picked. So taste one fruit before you harvest the rest.
• The orange colour only develops at cooler temperatures: in the tropics, ripe mandarins sometimes stay green.
• The clementine is probably a cross between a mandarin and a sweet orange.