Posted: 21/06/2014 at 15:06
They bloom in summer but not through the summer. I don't find they're worth the space for the short display they give.
A good way to find out about what looks good in a garden at this time of year is to visit some. The big ones or those that open for the NGS and local charities. Garden owners are usually willing to tell you about their plants.
You'd do better with some hardy perennials plus plants like dahlias and salvias for flowering through the summer