Hi Dave,
Some of your questions' answers will be better answered if we knew what area of
the country you live in and what your garden zone is.

Here in zone 7, SE WA, arid, I'd plant moss in the spring and I use water
hyacinth in my veggie filter and watercress in my waterfall.
Some plants are actively discouraged and outright illegal in some parts of the
country (SE USA and water hyacinth come to mind).
In the winter I don't heat my pond. I usually use an air pump and bubbler to
keep a hole open in the ice or a stock tank heater.


kathy :-)
algae primer
http://hometown.aol.com/ka30p/myhomepage/garden.html