The choicest milkvetch in the immediate Denver area is this tiny cushion plant: pretty much restricted to the foothill rock outcrops near Denver up to central Wyoming. It can make huge cushions, like vegetable sheep, in parts of it range. It is one of a half dozen "Orophaca": this has been used as a sectional name and also an attempted generic. They are the densest, most wonderful cushion plants in the genus--centered in Wyoming and northern Colorado. Astragalus gilviflorus shown in the other post is in this group (the least cushiony of all). The biggest cushions are formed by Astragalus hyalinus, and those can be three feet across and very hummocky. Alas, it has inconspicuous lilac flowers. The real queens of the Orophaca section are A. tridacylicus, A. sericoleucus and A. aretioides, all of them forming dense cushions studded with tiny pink flowers: they are distinguished by all sorts of minutiae, and all three are worth growing. This one was in my old garden on Eudora: must get it back! The yellow is Eriogonum ovalifolium from the Uinta Basin. Penstemon thompsoniae in front.
I like it, but then I have a thing for astragaluses! After such a wet winter (and a probable wet early spring), I'll try to get out and wander a bit, photograph some plants, and mark them for later seed collection.
Love Astragalus and Oxytropis but they hate our climate....even our few native species are reticent to grow in my area.
Thank you for the information the only one I am familiar with is the Astragalus gilviflorus. The rest all sound intriguing. Collecting seed must be hard as I know A. gilviflorus holds it's seed way down in the tuft. Makes it hard to find them.
A. gilviflorus is a tough one to collect seed from (I haven't managed yet), but it's more common with other species that the flower clusters are out at the ends of blooming stems, and thus easily accessible... which is great for those of us who enjoy seed exchanges! :)
Panayoti, I grew this one many years ago in the sand bed and loved it, but it never looked like the one in your picture! It's no longer with me, alas. Just recently switched to digital so most of my pictures are slides, including one of the albino form of Oxytropis podocarpa, which Joe and I saw with you in the Mosquitos many years ago.