Rich,

In some cases a newly set up tank will make almost anything grow as if
there's no tomorrow.
When I initially set up my 55 gal. I'd return from work and see a
brand new 3 inch leave of Aponogeton crispus that was not there in the
morning. Every sinlge day. Some other plants grew in a similar way.
Some did not grow at all though.
I had 2 wpg and the growth was out of this world. For about 2 weeks
that is.

What you see is totally normal. Later you will try to emulate it
using traces, Iron, and what not. It will never be the same insane
growth rate though.