Omg, I have to worry about the polar vortex also! From what I read, I think this latest (or soon to happen in your country?) warming event should put it to an end for the season. I've been getting info from this page for long term event info, like the polar vortex, El Nino, etc. https://www.severe-weather.eu/
It's been kind of fun to mentally prepare with this info, plus getting to nerd out a little.
I wish I knew more about flowing trees :( I've had great luck just emailing local professors/experts with plant questions, they usually get pretty excited because they get to knowledge dump on somebody new for once lol.
When do the bumblebees start to come out in your area?
That's why I'm going backwards from Magadan to Cape Town! See you at the end losers!!! /S