Cold hardiness & minimum temperature

Is Rumberry (Myrciaria floribunda)cold hardy? Hardiness zone & min temp

Also called Guavaberry, Murta, Cainitillo.

More about rumberry

About Rumberry

Myrciaria floribunda · also called Guavaberry, Murta · edible

Rumberry is a slow-growing Caribbean and Central American tree in the Myrtaceae family, producing small, dark-purple to black fruits with a spicy, aromatic flavour — the traditional base of St Croix and Virgin Islands guavaberry liqueur. It prefers well-drained, slightly acidic soil and tolerates dry spells once established. Not known to be toxic to pets.

Cold limit: USDA 10–12 · RHS H1c (18–35°C; damaged below 4°C)

Watch for — Fruit drop: Erratic watering or low temperatures during flowering cause premature fruit drop.

What rumberry's hardiness rating actually means

Rumberry is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Its RHS rating of H1c means: Warm-temperate — can summer outdoors but must come in well before the first frost. On the US scale that maps to USDA 10–12 — 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 °C (and never frost). Rumberry has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for rumberry as it gets too cold:

Below about about 5 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches.
A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover.
Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.

Can rumberry go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 5 °C, in shade or dappled light, hardened off gradually.
Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C.
It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

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 rumberry can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1c figure above.

Rumberry hardiness — frequently asked questions

Is rumberry cold hardy?

Rumberry is not cold hardy. It is a tropical houseplant that dies if it is left out through frost — there is no zone where it overwinters outdoors in a UK or cold-US climate. Indoor-only in almost every home. Rumberry can only live outside year-round in genuinely frost-free climates (roughly USDA 10–12); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature rumberry can survive?

Minimum survivable temperature is roughly about 5 °C (and never frost). Rumberry has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

What hardiness zone is rumberry?

Rumberry is rated USDA 10–12 and RHS H1c — Warm-temperate — can summer outdoors but must come in well before the first frost.

Can rumberry survive winter outside?

It can holiday outdoors in summer once nights are reliably above 5 °C, in shade or dappled light, hardened off gradually. Bring it back indoors well before the first autumn frost — do not wait for a frost warning, move it when nights drop toward 10-12 °C. It will never overwinter outside in a temperate climate; the indoors is its winter home, full stop.

What happens to rumberry below its minimum temperature?

Below about about 5 °C, growth stalls and the leaves start to show cold stress — dark, water-soaked, or yellowing patches. A single light frost blackens the foliage; a hard freeze kills the whole plant, roots included, and it does not recover. Even a cold, draughty windowsill or an unheated porch in winter can be enough to damage it permanently.