Cold hardiness & minimum temperature

Is Echinodorus grisebachii 'Bleherae' (Echinodorus grisebachii 'Bleherae')cold hardy? Hardiness zone & min temp

Also called Bleheri Amazon sword.

More about echinodorus grisebachii 'bleherae'

About Echinodorus grisebachii 'Bleherae'

Echinodorus grisebachii 'Bleherae' · also called Bleheri Amazon sword · tropical

The botanically corrected name for the classic broad-leaf Amazon sword, a large green rosette and one of the most popular background aquarium plants. Vigorous, adaptable and undemanding, it feeds heavily through its roots and multiplies from adventitious plantlets, quickly filling the rear of a tank with lush, lance-shaped foliage in moderate light.

Cold limit: USDA Tropical aquarium plant — not frost hardy; keep indoors above 18°C (22-28°C)

What echinodorus grisebachii 'bleherae''s hardiness rating actually means

Echinodorus grisebachii 'Bleherae' 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 H1b means: Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season. On the US scale that maps to USDA Tropical aquarium plant — not frost hardy; keep indoors above 18°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 10 °C (sustained cold below this is damaging). Echinodorus grisebachii 'Bleherae' has no frost tolerance at all — it is an indoor plant in any climate with a real winter.

Concretely, for echinodorus grisebachii 'bleherae' as it gets too cold:

Below about about 10 °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 echinodorus grisebachii 'bleherae' go outside or overwinter — and where?

It can holiday outdoors in summer once nights are reliably above 10 °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 echinodorus grisebachii 'bleherae' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H1b figure above.

Echinodorus grisebachii 'Bleherae' hardiness — frequently asked questions

Is echinodorus grisebachii 'bleherae' cold hardy?

Echinodorus grisebachii 'Bleherae' 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. Echinodorus grisebachii 'Bleherae' can only live outside year-round in genuinely frost-free climates (roughly USDA Tropical aquarium plant — not frost hardy; keep indoors above 18°C); everywhere else it is a houseplant that summers out at most.

What is the minimum temperature echinodorus grisebachii 'bleherae' can survive?

What hardiness zone is echinodorus grisebachii 'bleherae'?

Echinodorus grisebachii 'Bleherae' is rated USDA Tropical aquarium plant — not frost hardy; keep indoors above 18°C and RHS H1b — Sub-tropical — a normal warm home is fine, but it cannot go outside in a cool season.

Can echinodorus grisebachii 'bleherae' survive winter outside?

It can holiday outdoors in summer once nights are reliably above 10 °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 echinodorus grisebachii 'bleherae' below its minimum temperature?

Below about about 10 °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.