I'm not familiar with your area, but if it's a neighborhood with manicured lawns and no weeds, the monarchs are unlikely to find any milkweed, unless there are butterfly enthusiasts in the area who've planted some. You can plant milkweed, but the butterflies you release now might not stay and use it, might move on. In the East monarchs migrate, but you might be in an area like south Florida where they don't.

Hopefully, somebody from California will answer your question.

Sherry