Colonial regiments

[Aztlantix]

Guys, can somebody enlight me on regiment recruitment in colonies?
As Russia I have 2 colonies - I took California from Mexico and Northern island from Japan. The difference is that I can recruit Japaneese regiments and even some Ainu guys, but i can't take no one from California.
What exactly is the problem?

 

[Shinkuro Yukinari]

Hokkaido has a lot more pops as opposed to California so it is more likely for it to have soldier pops

 

[Aztlantix]

Oh, really. Pretty big difference actually

 

[Wimpola]

You can spend a national focus to increase soldier population in California if you really want a garrison there.