Where are you located, has HWA attacked the hemlocks in your area yet? In my opinion the eastern hemlock is doomed in most parts of the country... you should consider Asian Hemlock such as Tsuga chinensis or Tsuga diversifolia. Both are immune to the disease and have the same great characteristics of the eastern hemlock. I have Tsuga chinensis and it does great in the shade, fast growing, and a really nice lime green color, which is a stands out nicely in a shade garden.

This spring I have finally located some non-cultivar variety of Tsuga diversifolia and will be replacing my dying eastern hemlocks with those. The Chinese hemlock is only hardy to zone 6, but Japanese hemlock is good through zone 4. Arnold Arboretum has written some great papers on the ability of these to species to ultimately replace the Eastern Hemlock.

Shawn

This post was edited by SC77 on Sat, Apr 6, 13 at 21:58

No sign of HWA and we have another two hemlocks that are healthy and thriving. No luck to date finding the Asian hemlocks around here.

Just wondering whether it is worth planting the new one.

I'm new to conifers, amazing trees!

No sign of HWA and we have another two hemlocks that are healthy and thriving. No luck to date finding the Asian hemlocks around here.

Just wondering whether it is worth planting the new one.

I'm new to conifers, amazing trees!

If you are east of the Appalachian chain, then I'd worry about HWA. West of it and you should be ok. I'd be more concerned about your elongate hemlock scale you already are facing. I would avoid not only T. canadensis, but T. caroliniana, T. diversifolia, Abies and Picea as well. Given the shade, yew may be your best bet (although they too have a small chance of being hit by the scale).

tj

tj,

Interesting read on HWA and EHS. The OP never specified the location, but this study found 0% scale on T. canadensis without HWA and over 80% on those with HWA...In other words, the two insects frequently appear together. T chinensis seems to be the best bet. Arnold Arboretum has found them to be totally resistant to HWA and this paper finds them to be most resistant to EHS as well.

Do you grow T. chinensis? I bought one from http://japanesemaplesandevergreens.com last year and it is doing great. However, it's very lime green, rather than the dark green needles I hear it described as. If I posted a pic, would you be able to confirm it's identity?

Here is a link that might be useful: Hemlock Papers

Interesting read, SC77, thank you for that. Given that EHS is only where HWA is, I can see the relationship.
I was going by the Penn State article linked below.

No, I don't grow chinensis (hardy to zone 6).

tj

Here is a link that might be useful: Penn State