Re. Aroid hardiness

[S.& R. Illingworth]

Here too Arisaema flavum doesn't show up until almost July 1.  We have had
our plants several years and so far they have been perfectly hardy.

Arisaema amurense is our first out of the ground and into bloom, quickly
followed by A. triphyllum, which is becoming a weed.

I noticed A. ringens just poking up a couple of days ago.  However, there is
no sign of another one planted near by.  And as yet I can't find A.
consanguineum or ciliatum.  Gone? -  or slow?

This summer we will be planting out several pots of A. sikokianum.  They
bloomed inside earlier, and are now going dormant.  We'll give them a cool
rest and then put them out. I just went for an exploratory poke in the
ground where one is planted outside.  I thought it was dead, but I found a
little spike getting ready to emerge.  And these were blooming in
Minneapolis in mid-May!

Sharon
near Thunder Bay, Ontario
USDA 4,
Min -40C/-40F with snow
Min without snow -20C/-4F
Max 30C/86F, rarely higher
Frost free days 110 on average