I have a large pond that had water lilies that were over 20 years old.
I wanted to clean out the pond, so I drained it. It turned out that
only one water lilly was left but that its tuber was over 200 feet long
and had grown in a serpentine pattern all over the pond with nodes
coming up at many different places. I broke off foot long sections to
plant. This time I put in concrete pads and placed the sections in lilly
pots placed on the concrete pads so the tubers could not escape. This
is working well. Now all I have to do to take care of the lilies is
take out the pots. Much easier than draining the pond.

I highly recommend trying to get the lilies out of the soil in the pond
and containerizing them unless you want them to take over.


Tony Raven wrote:

We have a largish natural pond in the UK - about 100ft across and 3ft
deep - in which we planted some water lilies about three years ago.
They now have a tall crown of leaves in the centre which I understand
means they need lifting and dividing next May/June.

This year I didn't have a lot of time but a half hearted attempt showed
they are not going to lift easily (i.e. I couldn't budge the room, which
is rooted in the bottom of the pond, not a container by hand or fork
leverage).

Draining is out of the question so its doing it in the water depth that
is there.

I also have concerns as last time I did a big spring clean on the
vegetation in the pond (mainly removing a load of invasive reeds) the
nutrients released by stirring up the bottom meant we had a major
duckweed problem all summer that didn't go until we got some decent
winter rain to flush the pond water through.

Any suggestions/hints would be welcome
--
Pardon my spam deterrent; send email to
18,000 gallon (17'x 47'x 2-4') lily pond garden in Zone 6
Cheers, Steve Henning in Reading, PA USA