What are some suggestions for flowers/plants whose roots will be in some water? (besides pond lilies)
There are an enormous number of plants that will survive with their roots submerged in water, as evidenced by the diversity of plant life growing in and around our local waterways. As with choosing a plant for any other site, you will want to consider the light available to the plant and the water availability before making a selection. Some plants will grow better in 6 inches of water and some at the pond's edge where the roots are occasionally dry. Some can tolerate wide variations in water coverage as rainfall comes and goes.
I suggest that you concentrate on native plants as those will be the most foolproof in this complicated setting. There is an excellent wholesale, native, aquatic plant website for Aquascapes Unlimited in Pennsylvania (http://www.aquascapesunlimited.com/Plant-Search) that allows you to enter an array of variables regarding water depth, sun exposure, flowering attributes, plant height, wildlife benefits and even deer resistance. You will be amazed at the variety of plants that will thrive in this habitat!
Courtesy of NYBG Plant Information Service