This is a stunning perennial to about 1metre each way that will get to full size in the one growing season.
The main point is the foliage which is a dark plum colour with silvery V shaped patterns on each leaf. It does flower and these are an added bonus in the autumn as these tiny balls of white stand out well above the leaves.
Cut it to the ground in late autumn and it will usually produce some foliage to hold you over the winter which is beyond most perennials.
It likes the sun and plenty of moisture and in fact can be in a pot in shallow water where it will look stunning. So as long as it is moist to wet and in full to part sun it will be a great foliage plant in any garden.