I purchased two tiny plants of this penstemon from the Denver Botanic Garden last spring. (Thanks to Mike Kintgen for collecting the seed and Michael Bone for growing it!) I stuck them in the ground in what is essentially western clay and they have grown and flowered beautifully! They are still flowering now on October 3 which is nearly time for our first freeze. If they continue to grow, I will have plenty of seed.
P. fasciculatus resembles P. pinifolius superficially and from a distance, but the size, foliage and flowers are different. I've attached two photos taken with my cell phone to give people an idea of what it looks like.