Possibly a silly Colocasia question

How do you tell when a Colocasia goes into dormancy? I read that I should reduce watering when it does. How do I know? I have this Illustris that is blooming, even though it's been frosty the past couple of nights (mid 30s). I don't want to have it gasping for water, but I keep reading how they can rot with too much water in winter. So, do I reduce water when it gets truly cold, or when the leaves die back, or what? Thanks in advance for tolerating an EE newbie question. No laughing. :)
Deb

This time of year you should see the new leaves starting to get smaller.
This is a factor of day length and sun angle. Though if they are covered by a tree that's loosing leaves.....that may not be readily apparent as in my case.
In the Colocasia they will start to go dormant usually by slowing down the production of new leaves.
Mine never do really go dormant inside they just sit there and sit there and.....

Once I see the smaller leaves I stop all watering and let them get fairly dry before giving them a drink.
Think Rubber Tree Plants in a Houseplant situation.

As yours are outside (staying there?) I'd probably stop hand watering now.
If you see them start to droop..water.
The worse case is they will brown a little at the tips.
Illustris does like it a bit wetter than the others in Winter, indoors at least.

Lovely plants BTW not exactly Newbie Quality. You did well!!
Ric

Ric: Yes, I'm going to leave them all right where they are over the winter. I'll follow your suggestions. Thanks for the info and for the encouraging words. I had good luck with the Alocasia I planted for the first time this year also, so I want to make sure they're all still alive to come back again next spring!
Deb