This has been my second year with 'Mystic Spires' in the UK, and it did not exceed 24". It stayed reasonably compact, and en masse it is terrific. Though I still love the tall, if somewhat untidy 'Indigo Spires', especially if planted amongst uliginosa, darcyi, and involucrata, they each give the others support. Both Mystic and Indigo are still flowering, JUST, when almost every other species has been badly frosted.

Robin.

So Robin, have some of your public gardens been doing mass plantings of Indigo Spires? Longwood Gardens in Pennsylvania has gone into this plant in a big way. This summer they had several patches of at least 40 X 20 feet and those plantings were jaw dropping. They staked each plant upright to about 3 feet and then let them spread out and go mad. By July it was a solid mass of blooms and in no way untidy. This year at home I fronted them with a hedge of Cuphea David Verity and the orange flowers of the Cuphea constrasted beautifully with Indigo Spires dark purple and also helped to contain the plants. From behind they were held in place by Salvia subrotunda. It worked rather nicely. The use of uliginosa and involucrata are certainly worth considering for next year, the light blue of the former would add a nice match and involucrata would stand out well and find support. For the orange contrast, Cuphea works better for me because I've never figured out how to grow decent darcyi.

I have not seen Indigo Spires much in public gardens but Mystic Spires has been used quite a lot this year. It is becoming quite popular here.