A wonderful site from the University of British Columbia (E-Fauna BC) has helped me learn more about local butterflies:
This site (NatureWorks)describes the Pine White Butterfly
as does this Govt. of Canada site:
This next site (Butterfly Garden) is also very informative, and introduced me to the Skipper, which is a small butterfly ~ and from this I've gleaned that my previous photo of the brownish butterfly on the petunia was actually a Woodland Skipper.
The caterpillar of the Pine White Butterfly eats conifer needles, so is considered to be some, a pest! Does that mean it might be a WEED of the butterfly world!?