When is the best time to clean a pond

[Rosymacposie]

I have a pond in my garden which was put in about 7 years ago.  There are quite a few mature trees nearby and as a result lots of leaves end up in the pond.  I really think the pond needs emptying, cleaning and some of the lilys need splitting as they are taking over a bit now.  Its a mixed pond with some goldfish and lots of wild life in.  Soooooo when is the best time of year to drain, clean, and split the plants?

[hippydave]

try this

http://apps.rhs.org.uk/advicesearch/Profile.aspx?pid=447

[Rosymacposie]

Many thanks Dave........great help.