get large and develop petals but before it actually opens, the petalsfall
off. We have three buds and this has happened on two of them.The third one is
still too small yet. We live in NW Indiana (zone 5)

Maybe not enough sun, or not warm enough...You are on the very edge of a lotus
growing zone...they like it hot and sunny. Jerri

http://www.fringeweb.com/Ponds/JerrisPond