Cold hardiness & minimum temperature

Is Seville orange (Citrus aurantium)cold hardy? Hardiness zone & min temp

Also called Seville orange, Bitter orange, Sour orange, Bigarade.

More about seville orange

About Seville orange

Citrus aurantium · also called Seville orange, Bitter orange · edible

Seville orange is a bitter, aromatic citrus grown primarily for marmalade, liqueurs, and essential oil rather than fresh eating. One of the hardier ornamental citrus, it tolerates light frost briefly and makes a handsome specimen tree. The intensely fragrant blossom is used in perfumery. Toxic to pets due to citrus oils throughout the plant.

Cold limit: USDA 9-11 · RHS H2 (5-32°C)

Watch for — Cold-induced leaf drop: Brief temperatures below 0°C or prolonged cold above 5°C cause leaf drop. Move containerised specimens to a frost-free glasshouse or cool conservatory in winter.

What seville orange's hardiness rating actually means

Seville orange is a tender fruiting plant, not a hardy one. It crops outdoors only in roughly USDA 9-11; in cooler zones it is a container plant moved under cover for winter. Its RHS rating of H2 means: Tender — survives a frost-free greenhouse or a very mild, sheltered spot. On the US scale that maps to USDA 9-11 — the zones where it can be left outdoors year-round.

New to these scales? The USDA hardiness zone map explained covers how the zone numbers work, and you can find your own zone with the zone finder.

Minimum temperature — and what happens below it

Minimum survivable temperature is roughly about 1 to 5 °C — tolerates cold but no real frost. Seville orange fruits in warmth and is set back or killed by frost.

Concretely, for seville orange as it gets too cold:

Below about 1 to 5 °C — tolerates cold but no real frost the foliage and any fruit are damaged; a hard frost can kill the whole plant.
A light frost typically scorches leaves and ruins the current crop even when the framework survives.
Roots in a container freeze far faster than roots in the ground, so potted specimens need earlier protection.

Can seville orange go outside or overwinter — and where?

It can stay outdoors year-round only in USDA 9-11; in a UK or cold-US climate it is a conservatory or move-it-indoors plant for winter.
Summer it outside in full sun for the best crop, then bring it into a cool, bright, frost-free room before the first frost.
A bright unheated (but frost-free) glasshouse or porch is the ideal overwintering spot — cool and dormant, never freezing.

Work back from your local frost dates with the frost-date calculator: the last spring frost and first autumn frost are what really decide when seville orange can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H2 figure above.

Frost protection for borderline seville orange

Seville orange is right on a hardiness edge in many gardens, so if you are pushing it, these measures buy it the margin it needs:

Move containers into a frost-free glasshouse, porch or cool room before the first forecast frost.
For borderline-zone ground plants, wrap the trunk and fleece the canopy, and mulch the root zone heavily.
Keep it on the dry side over winter — cold plus wet roots is what actually kills tender fruit.

Seville orange hardiness — frequently asked questions

Is seville orange cold hardy?

Seville orange is a tender fruiting plant, not a hardy one. It crops outdoors only in roughly USDA 9-11; in cooler zones it is a container plant moved under cover for winter. Frost-tender. Grow seville orange in the ground only within USDA 9-11; everywhere colder it lives in a large pot that comes into a frost-free space each winter.

What is the minimum temperature seville orange can survive?

Minimum survivable temperature is roughly about 1 to 5 °C — tolerates cold but no real frost. Seville orange fruits in warmth and is set back or killed by frost.

What hardiness zone is seville orange?

Seville orange is rated USDA 9-11 and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can seville orange survive winter outside?

It can stay outdoors year-round only in USDA 9-11; in a UK or cold-US climate it is a conservatory or move-it-indoors plant for winter. Summer it outside in full sun for the best crop, then bring it into a cool, bright, frost-free room before the first frost. A bright unheated (but frost-free) glasshouse or porch is the ideal overwintering spot — cool and dormant, never freezing.

How do I protect seville orange from frost?

Move containers into a frost-free glasshouse, porch or cool room before the first forecast frost. For borderline-zone ground plants, wrap the trunk and fleece the canopy, and mulch the root zone heavily. Keep it on the dry side over winter — cold plus wet roots is what actually kills tender fruit.