Mine has started to grow what seems to be flower heads. I'm assuming these should be above the water line for any flowers to form.

Mine did the same thing last fall. I tried to grow a few of them emmersed but failed. Those that remained submersed in my 75g also died off.

Could it be that these are an "annual" type of plant or did I just kill them?

I've seen them in sandy rosemary scrub in FL.
They get submersed for awhile, then flower, then die.

We are able to grow them easy vegetatively for long time frames due to stable conditions.

To reproduce them in large numbers, seeds are the best method.

Regards,
Tom Barr

Hmmm so there's a chance mine will die off then? I read that they can be propagated by splitting the crown. Any truth in this?

Here is a good thread on how to propagate eriocaulon cinerum. I started off with 3 plants and had well over 20 of them when they began to flower. Unfortunately, not a single plant made it through last winter with maybe the exception of the one I gave to Tom.

Thanks. I have one plant that definitely shows signs that I can split it.