The plants are put in a pot with dirt, usually heavy clay type, unless they
are "floaters" such as hyacinth or water lettuce - some people put gravel on
the pond floor and let them root into it, instead of pots - plant roots
won't penetrate the liner (with the exception of bamboo) . The floaters get
nutrients from the pond water (helps to clarify it). The potted type get fed
from fertilizer you give it, or from the crap collecting in the gravel on
the bottom

Gale :~)

My question is this: If, as I understand it, the pond needs oxygen in the
water to keep from stagnating and to support fish, and if certain plants
are
generally used for this purpose, and if one needs a liner in the pond to
keep the water from seeping back into the earth, how are the plants to
take
root? Obviously they can't get any nourishment from the pond liner and
would
damage it if the roots penetrated it.

I'm having a real problem getting a grasp on this concept. And and all
help
will be appreciated, as I am trying to plan my first pond.