Tell us more about your site, soil and the kind of conditions you are giving it. Also the botanical and cultivar name if possible - that might be helpful - and where you got the trees.

They seem to do great around the Sequim area, irrigated or not. I have seen a number of large ones thriving around the area. However, I am aware of one nursery in the Sequim area that was selling grafted Arizona cypresses, and the grafts have not been long-term compatible. The trees grow fine for a couple years and then die off because of the incompatibility of the rootstock with the scion. Really there's no point in grafting this species at all; it's relatively easy to propagate from stem cuttings in late fall and (AFAIK) should be grown on its own roots.

Must be your site conditions - including perhaps even a pathogenic condition attacking cypress family conifers there - or cultivation methods. Blue forms of Arizona cypress common items at outlets here. Inherent hardiness of the species is not an issue: an Arizona cypress in the southern WA Cascade mountains (Carson, WA) was 68' tall in 1990. A 'Blue Pyramid' in Seattle was 35' tall several years ago. However, it's possible something about your situation is preventing your plantings of this tree from overwintering successfully.

Since these grow fast the problem I have encountered is trying to find ones that aren't root-bound. A 'Carolina Sapphire' I had going well on Camano Island went right over during the comparatively heavy snows we had awhile back.

Carson is mapped in Sunset Climate Zone 3A and the San Juan Islands are designated Sunset Climate Zone 4 in the Sunset WESTERN GARDEN BOOK (2007, Sunset Publishing, Menlo Park).

One difference that might be significant with this particular species is that it is liable to be hotter in Carson during the summer than where you are. This may be affecting ripening of growth and the attainment of the plant's full amount of hardiness.

San Juan island has a unique summer climate for the Pac NW coast, with cold nights because Puget Sound is nowhere more than 4 miles away. During the day, my garden, built on bedrock, often reaches 100 degrees in August.

Most of my beds are fairly shallow, and i am guessing that the cypress is planted in 3 feet of rich soil with flat glacially polished bedrock below it. Could it be that this desert tree, puts down a deep taproot, and when it get stopped, the tree becomes more vulnerable to the excesses of weather?

My soil is fairly neutral. That same large bed is now bursting with delphiniums, alliums, viburnum, a persimmon tree, and several old roses.

The conifers that are thriving in my garden are tall Irish junipers, a very old miniature blue spruce, and a large deodar which is thriving despite the confines of its bed.

Wells Nursery is nearby on the mainland, and they have a huge selection of unique conifers. I may stop by at their half price sale in a few weeks, and pick out something columnar that I've never tried before. I kind of think a pine would be a better choice for that spot.