These are known to tolerate wet in winter but you would have to check on the veriety wether they are drought tolerant in summer assuming the wet area does dry out completely in summer Blueberry "Patriot" the Dogwoods, the Willows and Birches and for a perenial perhaps Japanese Anemone, just to give you an idea

Why not try a 'Carpenteria'. Scented white flowers at this time of year, and grows to 6-8ft. A truly beautiful shrub.