Dear Susan, our Hibiscus here are hardy and can take snow and ice! I treat mine with G.H,N. which means General Horticultural Neglect and they seem to prefer that once established.
Heuchera or most of them like a shady place, they do not like a lot of sun and indeed being in a shady place not too much water. Though they are tough plants, but I am not sure if you can grow them in Canada!
It was the coldest winter on record in the UK in February and went down to minus 27F where we live and in some places minus 37.7F and it did not touch mine!
Hope this helps.
regards.
Neil.