Sometimes called 'sweet flag', this rhizomatous perennial grows in fans of slim strappy leaves like a grass, although it is actually a member of the arum family of plants. The cultivar 'Ogon' has beautiful chartreuse striped leaves 30cm long and will willingly grow in any soil (even in a shallow pond) except one which is bone dry. It copes with sun or shade, being more lime-coloured in shade and more brassy-yellow if grown in full sun. It will form a good-sized clump without every becoming invasive, and is attractive all year round.
It is a pretty edging to complement other leaf shapes (as illustrated at right) and to bring a contrast of colour to plantings of plain green leaves. It has insignificant flowers. Like all lime-coloured foliage, it teams well with flowers of blue, purple and orange. It is an extremely tolerant plant, being completely frost hardy as well as growing in warm humid climates.