One almost needs to step back a bit and look at the ecology of these species as they exist in nature-primarily as long-term seral dominants in their respective plant communities. As such, they got there following disturbance of some kind, be it fire (likely), logging operation, windthrow, or any other pallette-cleansing event. Survival is one thing, but to see these species thrive, they need sunlight.

I've got a woods full of native Thuja occidentalis up at my tree farm place. Yes, new babies can be seen in shade but if you want to see vigorous explosive growth and colonization of new ground, that's happening out in the sunshine. I suspect that for your spruce species, the same game is being played.

Even Canadian hemlock, that pine-family member always touted for its shade tolerance, is far and away most numerous (as youngsters) in sunny pockets. So a large tree tipped over, shafts of light are hitting the forest floor, and this is where you will find the pine-family members colonizing.

Black spruce in particular, if it's found at all, will be seen oc cupying areas of poor to no drainage, but definitely out in full sun, right alongside the tamaracks which need the sunlight as well. If you ever venture far to the north Whaas, say along H. 32 in the Nicolet National Forest, large expanses of primarily black spruce/tamarack can be seen, always in the sun.

I guess I'm not really answering your question though. These things run along a continuum, with the exact conditions at any given site yielding a range of plant fullness and vitality. Almost going to have to just try it and see what you get, I think.

+oM

I think you had some failures last winter with Engelmann spruce but correct me if I'm wrong about that.

I remember reading about seedling establishment of Engelmann and it was said that the engelmann's would start under other species in prevalent shade and eventually take over the area.

From the article linked below:
"Reaction to Competition- Engelmann spruce is rated tolerant in its ability to endure shade (24). It is definitely more shade-enduring than interior Douglas-fir, western white pine, lodgepole pine, aspen, western larch, or ponderosa pine but less so than subalpine fir (the most common associate throughout much of its range), grand fir, white fir, and mountain hemlock. The Engelmann spruce-subalpine fir type is either a co-climax type or long-lived seral forest vegetation throughout much of its range. In the Rocky Mountains of British Columbia and Alberta, and south of Montana and Idaho, Engelmann spruce and subalpine fir occur as either codominants or in nearly pure stands of one or the other. In the Rocky Mountains of Montana and Idaho, and in the mountains of Utah, eastern Oregon and Washington, subalpine fir is the major climax species. Engelmann spruce may also occur as a major climax species, but more often it is a persistent long-lived seral species. Pure stands of either species can be found, however (6)."

The problems I've encountered with engelmann are those on their own roots. They up and die during summer. Grafted engelmanns do very well though.

Dax

Here is a link that might be useful: Picea engelmannii Parry ex Engelm.

Dax, you make a good point here, and one which runs somewhat counter to my own.
It is true, if one looks into the woods in areas where spruce grows, such as the northwoods of my own state, there are indeed vast acreages of birch/aspen, all underneath of which are numerous spruce and balsam fir seedlings and saplings coming up. Now the balsam fir is a known quantity when it comes to shade tolerance, but it appears most spruce species have some of that ability as well.

Nevermind Whaas........what I said above. While there is some truth in it, I had forgotten the whole notion that Dax brought to the fore here-that spruce can and often does get started in the light shade of deciduous pioneer species.

+oM

One of my favorite topics, since I love conifers, but have a property with minimal full sun spots.

In my experience pungens will punch you in the face if they are placed in shade, yet engelmann will tolerate it rather well (at least when young). We will have to see if it continues to thrive as it ages. The same is true here with pinus strobus, they will grow in hemlock dense shade when young and still look full and healthy, but they are just waiting for an "event" to occur, that will allow them to surge up toward the sun. At some point in their maturity, I assume they begin to decline if no opportunity for sunlight is presented

Tom & Dax are both correct about looking to the species natural habitat and response to competition, to gauge how the cultivars of that species will handle shade. Searching the web for "shade tolerance" of conifers will generally yield the same answers about yew & hemlock. To dig deeper, you need to read through some of the scholarly papers that have been written, some of which have actually run controlled experiments on growth rates and overall health of conifers when covered with 30%, 60%, ect... shade cloth.

So far, I have had really good luck with Abies concolor in just a few hours of direct sun, then bright shade. I decided to give it a shot after finding one growing in very dense shade near my house. It was a little bit sparse, but considering the amount of deciduous shade it was growing in, I was very impressed. lasiocarpa is supposed to do even better, but I have not yet experienced with this species.

For my shaded spots that I don't want to use tsuga chinesis or diversifolia, I plan to use conifers with white/light foliage such as Picea orientalis 'Sulphur Flush', Cryptomeria japonica 'Knaptonensis', & Picea sitchensis 'Bentham's Sunlight'.

*Also, I have been planning to get more scientific about how much sunlight my conifers get, as it changes from season. I found this really cool YouTube video on how to use a solar analog alarm clock to record direct sunlight hours precisely.

Measure Direct Sunlight Hours Video. That alarm clock can be found on amazon for $14Equity by La Crosse 65901 Hybrid Solar Analog Alarm Clock

This post was edited by SC77 on Mon, Nov 17, 14 at 16:48

Gents, thanks for the info!

I've been looking to add dwarf conifers under the canopies of some of my deciduous trees on the lot line.

I already have various cultivars of Picea glauca, mariana, abies and engelmannii. Some Chamaecyparis as well. Its a bit too windy for hemlock and yew on my lot.

If I can be selective with the species that will still fill out with reduced vigor I'd rather stick with these.

I find deciduous shade more forgiving. While the trees are leafless and the ground not frozen (spring and fall), the conifers gain more sun. Now, I'll grant you that this fall around here there was maybe 3 hours from leaf drop to ground freezing (LOL), but that's not usually the norm.

tj