Cold hardiness & minimum temperature

Is Glory of the Sun (Leucocoryne ixioides)cold hardy? Hardiness zone & min temp

Also called Glory of the Sun, Chilean Garlic.

More about glory of the sun

About Glory of the Sun

Leucocoryne ixioides · also called Glory of the Sun, Chilean Garlic · flowering

Leucocoryne ixioides is a delicate, bulbous perennial from the coastal ranges of central Chile, producing fragrant, star-shaped flowers in shades of lavender, blue, or white with a white centre on slender stems in spring. It belongs to the family Amaryllidaceae (formerly Alliaceae) and carries a faint garlic scent in the leaves when crushed. In the UK it is best grown in a cool greenhouse or lifted annually as it needs full sun, sharp drainage, and a bone-dry summer. Toxicity to pets is unconfirmed; treat with caution.

Cold limit: USDA 9-11 · RHS H3 (2°C to 25°C; optimal 10–18°C during growth)

Watch for — Pale, washed-out flowers in low light: Flower colour (particularly the lavender-blue shades) fades significantly in insufficient light. Ensure the plant receives maximum winter and spring sun. In a cool greenhouse, position bulbs in pots at the highest, sunniest point of the structure.

What glory of the sun's hardiness rating actually means

Glory of the Sun is half-hardy (RHS H3). 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 H3 means: Half-hardy — comes through mild UK winters outside but is killed by a hard freeze. 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 −5 to 1 °C — a light, short frost only. Glory of the Sun shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for glory of the sun as it gets too cold:

Down to roughly about −5 to 1 °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 glory of the sun go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 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 glory of the sun can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H3 figure above.

Frost protection for borderline glory of the sun

Glory of the Sun 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.

Glory of the Sun hardiness — frequently asked questions

Is glory of the sun cold hardy?

Glory of the Sun is half-hardy (RHS H3). 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 9-11 (and sheltered UK gardens) glory of the sun can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature glory of the sun can survive?

Minimum survivable temperature is roughly about −5 to 1 °C — a light, short frost only. Glory of the Sun shrugs off cold nights but a real, sustained freeze will kill it.

What hardiness zone is glory of the sun?

Glory of the Sun is rated USDA 9-11 and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can glory of the sun survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 9-11 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 glory of the sun 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.