Desert 'Alpines'

There are quite a few varieties of Echinocereus viridiflorus that show at least some degree of hardiness. Echinocereus viridiflorus var. viridiflorus being the hardyest. It can be found as far north as south western, South Dakota. It follows the front range of the Rockies south into Texas and New Mexico. The other varieties come from west Texas and eastern New Mexico.
The taxonomy is in flux (a muddle) with Echinocereus russanthus being given species standing recently, that could change again as it has in the past. :rolleyes:

Here are the varieties I am able to grow.

Here we have one of the little understood members of the tribe Opuntia. Grusonia pulchella's range is from the eastern edge of the Sierras in California across central Nevada into the western counties of Utah. It is found growing in sandy dry habitats around the shore lines of playas, dry drainage channels, and sandy slopes. G. pulchella produces a large tuberous roots that store reserves of moisture.It grows in areas that receive about six inches of moisture per year.

The hardiest of the hardiest, and the most widely distributed of the Opuntias. Found growing in portions of 22 States, and 5 Canadian Provinces. This small mounding Opuntia is the most cold tolerant cactus in North America. It can be found growing almost to the Arctic Circle in Alberta and British Columbia.
As the scientific (Opuntia fragilis) and common names (brittle prickly pear) imply, the pads detach easily at the slightest touch. This allows it to vegetatively propagate itself.

I realize ice plants aren't for everyone...but these two may have a wider appeal than you might suspect. Bergeranthus are largely from the east Cape, and I find them quite tolerant of summer water: both Bergereanthus jamesii and the second image, Ebracteola wilmanniae have been growing in my rock garden alongside drabas and saxifrages and sempervivums. They have a very long bloom period and wonderful dense habit: I actually had the Ebracteola blooming this year in December and January between snowstorms!

The teeny tiny treasure is Escobaria sneedii ssp. sneedii. The tiny white marbles stacked one on top of another look like they should tumble and roll away. They stay put however with only an occasional escapee.
These are found in New Mexico through to western Texas and grow in very well drained sights that receave some summer rain. Winters are dry with lows of 10 F. My two plants withstand temps down to 0 F for the past five years showing no sign of damage.

I shall not ever forget finding this on the open veldt not far from Springfontein as my friend from Kirstenbosch and I drove towards the Drakensberg in the Orange Free State: January 1994 it was, late in the afternoon and we began seeing incredibly irridescent patches of pink in the late afternoon light. I collected a pinch of seed off a precocious pod, and germinated it the following May in Denver.

Native to the Colorado Plateau Province of the western United States. Winter wet sensitive but cold hardy with great long hooked spines. It grows well for me. Sclerocactus parviflorus flowers come in various colors usually rose to purple, pink, there are also multicolour, yellow, white.

I was given this amazing plant five or more years ago by David Salman: I'm not entirely convinced it doesn't represent a hybrid with Pediocactus simpsonii. Once it's finished blooming, it's going into a trough with another (much paler) P. despainii. I agree with John Weiser that it is beyond stupid that we cannot import these from Canada.

By the way, this just sits outside all winter in its dinky pot: does just fine through -20F we had this year!

I posted some pix elsewhere of this great group that is so incredibly abundant and variable in much of the West. Two more pix: the first is of the common form just west of Denver (much of it, alas, destroyed by housing) we call the snowball. There are white spined pedios elswhere in the West. I have a wonderful pale pink one from Monarch Pass, and I saw wonderful white spined pedios from Wyoming grown by Bob Johnson in Utah. But the soft pink flowers of our local frorm are the best in my opinion. Alas, it crosses much too easily!

Cold hardy, moisture tolerant, low growing form, beautiful flowers,adaptable- -Five key phrases to look for, when choosing a cactus to fit into your rockgarden.