no expereince .... but

i dont see how shade affects ambient humidity ... nor humidity at night ...

good luck ... try some.. its the best way to learn ... how it all works in your micro climate

ken

I love mertensiana. I've tried 'Bumps's Blue' and two 'Elizabeth' to no avail here in southern Indiana. The bump's blue held on for three years and dropped so many needles that I thought it had died every year. It grew so little and got eaten by rabbits. I chucked whatever was left of it. The 'Elizabeth' just fried in the hot sun. I should have given it a chance in some shade like you were thinking.

I'd say give it a try with a less expensive small one and afternoon shade. =)

The Arnold arboretum has 1 (Species) from 1977 that is still listed in Excellent condition. Katsura Garden's in Plymouth, MA (6b) has also had customers in the area that have had good long term luck growing 'Bump's Blue' see his post/picture here.

http://forums.gardenweb.com/discussions/1823062/tsuga-mertensiana-mountain-hemlock-for-sale-in-northeast

http://arboretum.harvard.edu/explorer/?id=693-77*A

I think the main issue with Western hemlocks growing outside of their native habitat is to obtain understock from the ideal part of their range that most closely compares to your local. Even in the PNW, "few mertensiana cultivars have been collected and grown. When dwarf plants are dug and planeted at lower elevations, they either suffer from change in growing conditions or adapt and show accelerated growth rates" - B. Fincham

Similarly, The Arnold arboretum has written in many of their papers about failed attempts to grow Tsuga heterophylla in the early 1900's, until they obtained plants from the interior portion of their native range (Idaho/Montana). They have 4 of those trees, all in good/excellent condition between 20-40 years old.

I think Bob Fincham was referring to stunted plants due to high elevation growing conditions, like shorter and cooler growing season rather than genetic dwarfs.

Garen, they're one of my favorite trees also. I have several and they do well here, both in the mountains and in the lowlands. They're at their best in the sub-alpine rainforest of the Olympic Mountains, one of my favorite hiking areas.

Mike

Yes, I understand that part, that the plants look like true dwarfs at high elevation, but bringing them down to lower elevation allows them to display their true (non-dwarf) growth rates. But, I thought I read several accounts of real cultivars being identified at high elevation, and when brought back down to lower elevations for observation they simply died or suffered due to the shift in altitude. I might be wrong, I'll have to dig around and see if I can find it.

Like many other west coast native plants, unlikely to do very well outside of a very similar environment. Which is pretty darn hard to replicate in most areas of the country. I wouldn't invest a lot in experimentation.

"I know that summer heat and humidity seems to be the main issue so some afternoon shade will be key"

Exposure to maximum ventilation is probably a better help than shade.

"i dont see how shade affects ambient humidity ... nor humidity at night ..."

It creates better growing conditions for pathogenic fungi and other pests / diseases. Conversely, dry air (as they get where they are native) is a very good disinfectant.

Resin

Thanks to everyone for the advice. Seems like I should try a mostly sunny spot perhaps with some afternoon shade, with some open exposure for air circulation. I'll let you know how it turns out with Bump's Blue.

Nice little lawsoniana there Mike! I'd be excited as heck if stuff like that volunteered in my yard! I tried to grow a few here. The experiment was short-lived.

+oM

I get about 20 a year that volunteer. Blue, grey, gold, and shades in between, but mostly green. So far I haven't experienced their tendency for root rot.

Mike

Here is my Tsuga mertensiana 'Blue Star'. I love it's color and "cedrus look":) My zone is 5b - 6a.

Stunning! Really, such a unique conifer in color, foliage, and ability to tolerate shade. I will try one this spring