One of the impossible conditions that people list online when they are looking for plants is, “Perennial which blooms all summer.”
One of the few perennials which fulfills these conditions is Calamintha nepeta – Montrose White. I’ve only grown this for a couple of years, but it is a pollinator favorite which blooms all season long.
Mine grows about 36″ wide and 24″ tall. I’d put it in front of the garden and let it cover an area with blooms. It would nice make a nice border or edging plant.
I found my locally at Greenscape Nursery In St. Louis.
Butterfly Gardening 