Cold hardiness & minimum temperature

Is Ludwigia glandulosa (Ludwigia glandulosa)cold hardy? Hardiness zone & min temp

Also called glandular primrose-willow, pearlwort Ludwigia.

More about ludwigia glandulosa

About Ludwigia glandulosa

Ludwigia glandulosa · also called glandular primrose-willow, pearlwort Ludwigia · tropical

Ludwigia glandulosa, often sold as 'Ludwigia Perennis', is a striking aquarium stem plant from the southern USA with wavy lance-shaped leaves that flush deep purple, burgundy and copper under strong light. It is moderately demanding, needing high light, CO2 and rich dosing to show its best colour and avoid leggy, green growth.

Cold limit: USDA 6-10 (native to southeastern US wetlands) · RHS H3 (20-28°C)

What ludwigia glandulosa's hardiness rating actually means

Ludwigia glandulosa 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 6-10 (native to southeastern US wetlands) — 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. Ludwigia glandulosa shrugs off cold nights but a real, sustained freeze will kill it.

Concretely, for ludwigia glandulosa 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 ludwigia glandulosa go outside or overwinter — and where?

It can live outside year-round only in the mildest, most sheltered part of USDA 6-10 (native to southeastern US wetlands) 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 ludwigia glandulosa 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 ludwigia glandulosa

Ludwigia glandulosa 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.

Ludwigia glandulosa hardiness — frequently asked questions

Is ludwigia glandulosa cold hardy?

Ludwigia glandulosa 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 6-10 (native to southeastern US wetlands) (and sheltered UK gardens) ludwigia glandulosa can stay out; in colder areas it must be lifted, brought in, or treated as a frost-tender plant.

What is the minimum temperature ludwigia glandulosa can survive?

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

What hardiness zone is ludwigia glandulosa?

Ludwigia glandulosa is rated USDA 6-10 (native to southeastern US wetlands) and RHS H3 — Half-hardy — comes through mild UK winters outside but is killed by a hard freeze.

Can ludwigia glandulosa survive winter outside?

It can live outside year-round only in the mildest, most sheltered part of USDA 6-10 (native to southeastern US wetlands) 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 ludwigia glandulosa 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.