What they’re like: Growing 2 feet tall from rushlike foliage, Dutch irises are marked by clear, intense colors such as deep blue, purple, and orange, usually with a yellow blotch on the falls (the petals that drape off the sides of each flower).

Our favorites: For blue, try ‘Professor Blaauw’; for magenta purple, ‘Purple Sensation’ (pictured); for yellow, ‘Royal Yellow’.

How to display: Mass irises among low ornamental grasses for a meadow effect. Or mix them in pots with yellow violas. They grow in all but the coldest parts of the West and naturalize even in mild climates.