It has been warm and all my plants started leafing, and now there’s snow in the forecast.  Will they survive?

What I want to know if the Japanese cherry blossom will grow in saskatoon, not the ordinary cherry

Probably, but without knowing what plants it's impossible to say for sure.

Depends on the plants and the actual temperatures as well as how long it stays cold.

In Florida, they used to use 'smudge pots' to add supplemental heat to the orange groves.

If it is just a few plants, you could cover them with dirt or a cloche.

Some people went so far as to place egg shells on the flowers of fruit trees.