Cold hardiness & minimum temperature

Is Queen Sago (Cycas circinalis)cold hardy? Hardiness zone & min temp

Also called Fern Palm, Queen Sago Palm.

More about queen sago

About Queen Sago

Cycas circinalis · also called Fern Palm, Queen Sago Palm · houseplant

Queen sago is a graceful cycad with long, arching, feathery fronds that give it a softer, more fern-like look than the common sago palm. Native to southern India, it grows into an imposing specimen over time. Like all cycads it is highly poisonous to pets and people, demanding careful placement.

Cold limit: USDA 10-11 (indoor in most US and UK homes; very frost-tender, damaged below about 0°C) · RHS H2 (18-30°C)

Watch for — Frost and cold damage: More cold-tender than the common sago; even a light frost browns the fronds. Keep it above about 5°C and well away from cold draughts.

What queen sago's hardiness rating actually means

Queen Sago 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 10-11 (indoor in most US and UK homes; very frost-tender, damaged below about 0°C) — 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. Queen Sago shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for queen sago 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 queen sago go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 10-11 (indoor in most US and UK homes; very frost-tender, damaged below about 0°C) 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 queen sago 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 queen sago

Queen Sago 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.

Queen Sago hardiness — frequently asked questions

Is queen sago cold hardy?

Queen Sago 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 10-11 (indoor in most US and UK homes; very frost-tender, damaged below about 0°C) (and sheltered UK gardens) queen sago can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature queen sago can survive?

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

What hardiness zone is queen sago?

Queen Sago is rated USDA 10-11 (indoor in most US and UK homes; very frost-tender, damaged below about 0°C) and RHS H2 — Tender — survives a frost-free greenhouse or a very mild, sheltered spot.

Can queen sago survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 10-11 (indoor in most US and UK homes; very frost-tender, damaged below about 0°C) 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 queen sago 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.