I did the studies a few years back comparing lily growth and bloom in pea
gravel vs. soil.
You need to be sure to use a slow release fertilizer that supplements
agents
soil usually contains (minerals, etc), not just the N, Phosph and Potash.
I
use what Longwood gardens uses.. highland rim. if you fertilize there is
no
difference in plant vigor/blooms. if you forget to (as I have done), there
seems to be less blooming, but no difference in leaf production.. that's
for
lilies.

Interesting - what is "highland rim"?