Good Ole Verbena

You just can't go wrong planting verbena in a flower bed.  Many of the better types will come back each year, they attract butterflies, they are covered in bloom, and they multiply.  If you bury runners, they will easily root and you can get new plants to put anywhere.  This is the most common type, Homestead Purple, and it's justifiably famous.  I put one lonely plant of this variety in my butterfly garden last year.  This one plant sent out runners and is coming back as about half a dozen new plants this year.  They overwintered this harsh year quite well and are already starting to bloom.  I'm letting them run all over my butterfly bed between all the taller plants and will only shear them back if they get leggy this summer.  They look great trailing from a container too.  Give them a try.  You won't regret it.