Agastache ‘Blue Boa’ PP#24,050 (Hummingbird Mint). With deep purple-violet blooms, Blue Boa is a sturdy upright grower that has large green leaves. It grows best in fast-draining soil and average moisture levels. Leave the stems in place over the winter months to improve cold hardiness. This perennial is a stunning hybrid variety of hummingbird mint that blooms from mid-to-late summer and has won the 2013 title of Too Good to Wait Performer at the Colorado State Perennial Trials. Seedlings will not be true-to-type and should be weeded out. 24″ tall x 18-24″ wide.