Cold hardiness & minimum temperature

Is Navel Orange Washington (Citrus sinensis 'Washington')cold hardy? Hardiness zone & min temp

Also called Washington navel orange, navel orange.

More about navel orange washington

About Navel Orange Washington

Citrus sinensis 'Washington' · also called Washington navel orange, navel orange · edible

The Washington navel is the classic seedless eating orange, recognised by the small secondary 'navel' at its blossom end. Sweet, easy to peel and self-fertile, it crops in winter and stores well on the tree. Frost-tender but forgiving, it makes one of the best citrus for a large patio container moved under cover for winter.

Cold limit: USDA 9-11 (overwinter under glass in cooler zones) · RHS H2 (13-30°C)

Watch for — Fruit drop: A normal 'June drop' thins excess fruit, but heavy drop also follows drought stress, cold draughts or feeding lapses; keep conditions steady.

What navel orange washington's hardiness rating actually means

Navel Orange Washington is a tender fruiting plant, not a hardy one. It crops outdoors only in roughly USDA 9-11 (overwinter under glass in cooler zones); 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 (overwinter under glass 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 1 to 5 °C — tolerates cold but no real frost. Navel Orange Washington fruits in warmth and is set back or killed by frost.

Concretely, for navel orange washington 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 navel orange washington go outside or overwinter — and where?

It can stay outdoors year-round only in USDA 9-11 (overwinter under glass 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 navel orange washington 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 navel orange washington

Navel Orange Washington 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.

Navel Orange Washington hardiness — frequently asked questions

Is navel orange washington cold hardy?

Navel Orange Washington is a tender fruiting plant, not a hardy one. It crops outdoors only in roughly USDA 9-11 (overwinter under glass in cooler zones); in cooler zones it is a container plant moved under cover for winter. Frost-tender. Grow navel orange washington in the ground only within USDA 9-11 (overwinter under glass 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 navel orange washington can survive?

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

What hardiness zone is navel orange washington?

Navel Orange Washington is rated USDA 9-11 (overwinter under glass in cooler zones) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can navel orange washington survive winter outside?

It can stay outdoors year-round only in USDA 9-11 (overwinter under glass 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 navel orange washington 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.