Cold hardiness & minimum temperature

Is Lisbon Lemon (Citrus limon 'Lisbon')cold hardy? Hardiness zone & min temp

Also called Lisbon lemon.

More about lisbon lemon

About Lisbon Lemon

Citrus limon 'Lisbon' · also called Lisbon lemon · edible

A vigorous, heavy-cropping true lemon and the main commercial rival to 'Eureka'. 'Lisbon' is more upright, thornier and notably more cold- and heat-tolerant, producing tart, juicy, near-seedless fruit mostly in a concentrated winter-to-spring crop. Its hardiness and dense canopy make it the better choice for open ground in marginal citrus climates.

Cold limit: USDA 9-11 (one of the hardier lemons but still frost-tender below about -3°C; container culture in cooler zones) · RHS H1c (15-32°C)

Watch for — Frost damage: Hardier than most lemons but still tender; new growth and fruit are killed by hard frost. Protect or bring containers under cover when temperatures approach freezing.

What lisbon lemon's hardiness rating actually means

Lisbon Lemon is a tender fruiting plant, not a hardy one. It crops outdoors only in roughly USDA 9-11 (one of the hardier lemons but still frost-tender below about -3°C; container culture in cooler zones); in cooler zones it is a container plant moved under cover for winter. Its RHS rating of H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 9-11 (one of the hardier lemons but still frost-tender below about -3°C; container culture in cooler zones) — 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 5 °C (and never frost). Lisbon Lemon fruits in warmth and is set back or killed by frost.

Concretely, for lisbon lemon as it gets too cold:

Below about 5 °C 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 lisbon lemon go outside or overwinter — and where?

It can stay outdoors year-round only in USDA 9-11 (one of the hardier lemons but still frost-tender below about -3°C; container culture in cooler zones); 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 lisbon lemon can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Frost protection for borderline lisbon lemon

Lisbon Lemon 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.

Lisbon Lemon hardiness — frequently asked questions

Is lisbon lemon cold hardy?

Lisbon Lemon is a tender fruiting plant, not a hardy one. It crops outdoors only in roughly USDA 9-11 (one of the hardier lemons but still frost-tender below about -3°C; container culture in cooler zones); in cooler zones it is a container plant moved under cover for winter. Frost-tender. Grow lisbon lemon in the ground only within USDA 9-11 (one of the hardier lemons but still frost-tender below about -3°C; container culture in cooler zones); everywhere colder it lives in a large pot that comes into a frost-free space each winter.

What is the minimum temperature lisbon lemon can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Lisbon Lemon fruits in warmth and is set back or killed by frost.

What hardiness zone is lisbon lemon?

Lisbon Lemon is rated USDA 9-11 (one of the hardier lemons but still frost-tender below about -3°C; container culture in cooler zones) and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can lisbon lemon survive winter outside?

It can stay outdoors year-round only in USDA 9-11 (one of the hardier lemons but still frost-tender below about -3°C; container culture in cooler zones); 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 lisbon lemon 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.