Typically, if you have an invoice from the seller, it'll specify all the artificially propagated hybrids or species. No orchid I've ever brought in has ever triggered a call for CITES application. Never been asked for one for commercially acquired plants.
Simply, if you declare them and go into the office, they'll clear them through the computer mediated Automated Import Reference System (AIRS).
Importing plants and plant products: what you need to know - Plants - Canadian Food Inspection Agency
Which will follow a flowchart of questions and answers from the officer as follows. Such as:
Orchids - yes
accompanying traveller - yes
for personal use - yes
originating (grown for 6 months) in the USA - yes
free of soil - yes
less than 50 - yes
and you are free to go home with your haul.