No strat needed, believe these are from South America. Surface sow, 70F for germinaton. Do NOT start these too early. Start them the same time you would start zinnias.

I normally don't put these out until mid-May and just plant them directly in the soil. Haven't been surface sowing, though, but they seem to come up OK even if lightly covered. These are great butterfly plants, I get tons of swallowtails all season and monarchs later in the summer. After that the goldfinches eat the seeds.

Larry

FYI Larry, Johnny's catalog is a good source of info on the seeds it carries. Sounds like these are very frost tender, so stratification might be a fatal error...