As I understand it,--- they are attracted to red and oranges.
Then when they get down to the garden they will enjoy any nectar plants.
I had one fly into my window ---attracted by the orange geranium on the inside.
I grow red petunias to bring them into the garden.
Petunia exserta is the hummingbird petunia.
It is red, but apparently it is pollenated by only a certain hummingbird, and not the ones we get here.
Other red petunias will bring them into the garden.