Cold hardiness & minimum temperature

Is Meiwa Kumquat (Citrus japonica 'Meiwa')cold hardy? Hardiness zone & min temp

Also called Meiwa kumquat, round kumquat, sweet kumquat.

More about meiwa kumquat

About Meiwa Kumquat

Citrus japonica 'Meiwa' · also called Meiwa kumquat, round kumquat · edible

Regarded as the best fresh-eating kumquat, 'Meiwa' bears round to oval fruit with a thick, sweet edible rind and milder, less acidic flesh than 'Nagami', so the whole fruit eats sweet. A compact, nearly thornless, cold-hardy citrus, it is slow-growing and ornamental, making it an excellent container plant for sunny patios and conservatories.

Cold limit: USDA 8-11 (one of the hardiest citrus; established plants tolerate brief drops to about -7°C / 20°F) · RHS H2 (13-30°C)

Watch for — Leaf drop in winter: Caused by cold draughts, dry indoor heat or overwatering during slow growth. Keep the plant bright and stable, and water sparingly in the cold months.

What meiwa kumquat's hardiness rating actually means

Meiwa Kumquat is half-hardy (RHS H2). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. 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 8-11 (one of the hardiest citrus; established plants tolerate brief drops to about -7°C / 20°F) — 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. Meiwa Kumquat shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for meiwa kumquat as it gets too cold:

Down to roughly about 1 to 5 °C it copes, especially if dry and sheltered.
A sustained hard frost collapses the top growth; whether it returns depends on whether the roots, crown or tubers froze.
Wet cold is far more lethal than dry cold for this plant — soggy, frozen soil is the usual killer.

Can meiwa kumquat go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-11 (one of the hardiest citrus; established plants tolerate brief drops to about -7°C / 20°F) or a frost-free UK microclimate.
In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter.
A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

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 meiwa kumquat 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 meiwa kumquat

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

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost.
Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse.
Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones.
Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.

Meiwa Kumquat hardiness — frequently asked questions

Is meiwa kumquat cold hardy?

Meiwa Kumquat is half-hardy (RHS H2). It survives a mild winter outdoors in a sheltered spot, but a hard frost kills it — so in colder zones it is lifted, potted, or grown as a tender plant. Borderline outdoors. In its mild end of USDA 8-11 (one of the hardiest citrus; established plants tolerate brief drops to about -7°C / 20°F) (and sheltered UK gardens) meiwa kumquat can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature meiwa kumquat can survive?

Minimum survivable temperature is roughly about 1 to 5 °C — tolerates cold but no real frost. Meiwa Kumquat shrugs off cold nights but a real, sustained freeze will kill it.

What hardiness zone is meiwa kumquat?

Meiwa Kumquat is rated USDA 8-11 (one of the hardiest citrus; established plants tolerate brief drops to about -7°C / 20°F) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can meiwa kumquat survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 8-11 (one of the hardiest citrus; established plants tolerate brief drops to about -7°C / 20°F) or a frost-free UK microclimate. In colder zones, grow it in a pot you can move under cover, or lift its tubers/roots and store them frost-free over winter. A south-facing wall, free-draining soil and a dry winter position can push it a full zone hardier than the books suggest.

How do I protect meiwa kumquat from frost?

Mulch the crown or root zone deeply with bark, straw or leaf-mould before the first hard frost. Move container plants against a warm wall or into an unheated but frost-free porch or greenhouse. Fleece the top growth on the coldest nights, and keep it on the dry side — dry roots survive cold far better than wet ones. Lift dahlia-type tubers or tender crowns after the first light frost blackens the foliage and store them somewhere cool but frost-free.