Or perhaps longer than 2 years. We don't take our pond down to the liner - I know some do do this. In the spring and the fall, the waterlilies are lifted and the entire pond is vacuumed. Once at start up and once at shutdown. It doesn't take long to vacuum and is not all that difficult to do.
In the Spring, when the waterlilies are lifted, they are then divided and fertilized. I use the once a year fertilizer stakes. Truthfully, if I had to fertilize once a month with the monthly waterlily tabs, it would probably only get done the first month at start up. In the fall, when the waterlilies are lifted, they are cut back so there is nothing in the water during the winter to rot.
There have been times where we have had to dump the pond and get everything out, but that does not happen that often. That was done more if there was a problem or if we had an overabundance of koi fry. We have found a method that now takes care of the koi fry as we had also exhausted all sources that would take the fry. Every Spring, we purchase a dozen or so bullfrog tadpoles - this has taken care of the koi fry problem.
So essentially, what I am saying is that the maintenance of the pond is minimal and not difficult. I know the larger ponds are supposed to be less maintenance than the smaller ones.
I am looking forward to start up here shortly. It is to a point where it is a rite of passage to Spring at our house!
Here are my waterlilies - all fertilized and ready to be put back into the pond.
