Echinodorus osiris (rubra) propagation

[henry]

My Echinodorus osiris has sent up a inflorescence about 2 feet above the waterline. From what I have read on the net, it will produce flowers and plantlets along this stem, but there is limited information.

My question is, do I have to get it back in the water for it to produce plantlets & roots? Will it produce roots without being in the water?  I just have buds on it now.

Appreciate any advise you can give.
Thanks
Richard

The picture at this site depicts it below the waterline.
http://www.tropica.com/productcard_1.asp?id=072