Lotuses are probably the most challenging of all the aquatic plants to grow. They are cold sensitive and can't freeze, so you either have to overwinter indoors or have a place to store them in the pond where they can stay below the ice.
Irises and lilies (aquatic lilies are not the same as daylilies however) are both great marginal pond plants. You have to be careful and watch them as they do grow quickly and would happily take over your pond. They need to be divided frequently to keep them in check.
Basically pond plants are divided into three categories - deep water plants (basically water lilies), floating plants (the two most common being water lettuce and water hyacinth) and marginals, which, as the name implies grow in the margins, or shallow areas of the pond. Those would be your rushes, sedges, irises, grasses, cattails, etc. You can also grow common garden plants in the shallow areas of your pond - things like impatiens and creeping jenny do great in and around rocks and waterfalls as do many of the other common ground covers. There are lots of pond pictures posted on the forum - check them out and if you see something you like, just ask. Everyone loves to share what works for them!
