I haven't grown that one, but try the seed growing forum. Someone there might be able to help.

This native of Mexico is an old-time garden favorite. Coral Vine (also known as Queen's Wreath or Queen's Crown)Hardy zone 7-10 (dies back in zone 7, but regrows from underground tubers in spring, Full sun to partial shade.Seeds can be direct sown in early spring after
all danger of frost has past.They germinate within six to ten days.
If you want you may also lift the tubers and store over winter in a
cool dry place.

Blueangel