Kate, I have to admit, the ones I planted in the ground petered out and died, too. I think they don't compete well with any tree roots or other competition.
I now keep them all in pots, with a very loose, humus-y mix and just move them around to where I want them to bloom. Sink the pots and cover the pot edges with mulch, then I can also move them under the tent in winter if it gets too cold.
This year I gave them all a little handful of alfalfa pellets each, some pelleted fert, and they do occasionally get the dilute fert spray that the other orchids get as well.
