My experience here in South Australia is that the plants do fine with
low humidity. In summer it can quite easily reach above 40C in
combination with _very_ low humidity and my plants do not suffer. I
do make sure they are well watered by standing them in 10 - 15 cm of
water during these days but apart from that they suffer the vagaries
of the local weather. You can see a difference in the plants that I
grow and others that get pampered in a glass house - mine seem more
robust with thicker walls to the leaves, I have won a few prizes for
my plants at the ACPS shows :-)
The symptoms described, to me, sound like either the rhizome has
rotted and had spread to the base of the leaves which will make them
go floppy very suddenly or the plant is declining slowly for some
other reason that I have not been able to work out. I lost a couple of
health S. Purpurea this way, could not work out what was wrong they
just shrivelled.
-- Brett Lymn, Computer Systems Administrator, AWA Defence Industries
===============================================================================
"It's fifteen hundred miles to Ankh-Morpork" he said. "We've got three
hundred and sixty three elephants, fifty carts of forage, the monsoon's
about to break and we're wearing ... we're wearing ... sort of things,
like glass, only dark... dark glass things on our eyes..."
- Terry Pratchett "Moving Pictures".