Where do I catch Vivillon in Violet? I checked the Islands on the East and Tagtree Thicket, and I have no idea how to get to North Province Area One without the rock climbing. I sent a postcard from Pokemon Go but they just aren't spawning anywhere. I ate a meal that increases bug (and another for flying) but that didn't seem to work either. Caught nearly every other Pokemon plus a shiny before finding Vivillon.

Is it a time of day thing? Do I need to power through these titans and just get to NP Area One?