pen,
I used roughly 70-80% grit(pea gravel, decomposed granite and pumice or whatever I could get my hands on) and to fill the balance I used composted manure. Drain freely but still retains moisture.

Thank you, that helps a lot. I may do something similar with grit and compost, and leave the topsoil out since ours tends to have a lot of clay.

A girlfriend in OKC uses 1/3 peagraval, 1/3course builders sand, 1/3 soil. She has been growing out out doors for awhile.

Thanks w. I could definitely make something like that. I think I'll mix up some samples and test them in a clear pot to get a better idea of what they look like and how they perform. I'm really excited to see how my Burseraceae and other trees do with free root run.

Have your pruners ready, trees with free root run will explode into growth once established. You'll also be surprised what plants don't like it, there were a few plants that didn't like the freedom.

I read in a book recently that you shouldn't bed out species with large tuberous roots (like Operculicarya decaryi) if you plan on potting them later because they may not fit into a pot without some serious surgery. Have you found this to be a problem? I thought about burying a mesh basket under some plants to contain the larger roots.

As for plants that may not do well in ground, I remember Pachypodium being recommended for containers, so I'll leave those out. Do any of these jump out as bad ideas for the raised bed?

Adansonia digitata
Adenium arabicum
Boswellia nana
Bursera fagaroides, galeottiana, linanoe
Calibanus hookeri
Commiphora eminii, monstruosa, kua
Dendrosicyos socotrana
Dorstenia gigas, lavrani
Fouquieria columnaris
Moringa drouhardii
Operculicarya decaryi, pachypus
Pachycormus discolor
Sedum oxypetalum
Senna meridionalis
Trichodiadema bulbosum
Tylecodon paniculatus
Uncarina grandidieri

The ones I would NOT put in the bed are the Adenium, gigas, Pachycormis and the Trichodiadema. These do best in cramped quarters. Operulicarya will be no harder to get out of the bed then anything else, they will all be a chore to get out after a couple of years anyway.

Thank you! I'll keep that in mind this summer.