I have grown to love cannas over the years although one has to say that seeing them in beds of mixed colours with nothing to soften them can be off putting, think council bedding. These statuesque plants should be used as features amongst other things such as ornamental grasses et.al.
Canna glauca could be said to be quite subtle for the genus with its narrow grey leaves and soft lemon orchid like flowers so even those of you who think of them as vulgar shouldn’t dismiss this stunning species.
It is known as a water Canna for good reason as it is quite happy in a pot in a pond and will give much better value in both foliage and flower longevity that the much lauded water Iris. They can also be grown quite happily in a moist soil in a sunny border or a large pot sitting in a saucer so there isn’t an excuse for not having on.
My plant started as a seed that I was given by Christopher Lloyd from one growing in the pond in his sunk garden at the world famous garden of Great Dixter so what a pedigree! They are in 20cm. pots and sell for $22.50. And whilst you are at it you could consider letting your hair down and buying a truly gaudy Canna as well! 
