Ray and Al,
Thanks for the information! Now know I'm not doing something to kill my
plants.

Ray, I'm disinclined to think it's a lack of fertilizer--I'm pretty
generous. BTW, the MSU formulation I got from you is great stuff.

Al, the root production above the leaves of the buyssonniana is really
amazing. Above the lower leaves, there are as many as five
roots--nearly as thick as pencils---erupting from the stem. Because the
roots' pressure on the leaves is forcing the leaves away from the stem,
I am assuming the leaves will die, but maybe not. So, perhaps your
theory of abscission triggering root growth might be right!