Dan,
I have not grown the M. cardinalis but have seen it growing naturally in a
fairly fast moving stream/waterfall area in the hills above Santa Barbara.
Here is a link to the Las Pilitas info on it
http://www.laspilitas.com/nature-of-...lus-cardinalis
I have and do grow Epipactis. I got some great plants from Las Pilitas Nursery.
You should visit them as they are just over the pass north of you. I would not use regular garden soil unless your soil is very sandy.
Plant the rhizome with the growing tip just at the surface of the soil or potting mix.
Once the leaves start to appear fertilize with Miracle Gro Liquid at 1/2 strength weekly until flowering occurs.
The plants will die back down in late fall or early winter.
I would recommend repotting every year into fresh soil or potting mix.