Question on planting aquatic plants

I live in the deep south (Centreal Alabama zone 9 IIRC) I have only
ever seen ice around the edges of my pond one time and its about 20
years old. Our water lines are only buried 6 to 10 inches
deep........so it shows how much serious freezing weather we get.
Mostly it never gets belowmid 30's and then its only for a couple of
days.......and I have only had frost a few times.

So my question is when would you plant aquatic plants like calla's.
iris, and water lillies........I have mainly hardy lillies but do have
a few tropical.

Since this is actually the first year we have fooled with plants in
and around the pond (natural clay / sand bottom pond 1 + acre, will
the water lillies I have growing now loose their leaves or do they
usually keep them all year around in climates that are not so cold..

I was just given a large bag full of hornwart. There is no roots, and
was told it can just be weighted down and placed in the pond Will
hornwart take up and grow roots..........can pieces be cut and simply
stuck in the ponds soil and be expected to grow ?

Thanks for any info or insight

I can raise animals and veggies but flowers and stuff are not my
forte.
..
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