How important is full sun for a Blue Spruce tree?

Question

We've been thinking about getting a living tree for Christmas this year. It's something I've always wanted to do, as it bothers us to throw away trees. We also need more trees for birds, squirrels, chipmunks, and anything else that wants to nest in or eat there.

We found a local grower who will dig the tree up, deliver it with the rootball intact, and teach us how to keep it healthy inside for about 10 days, at which point we can plant it outside. We went to the farm and picked out a Blue spruce (Picea pungens), which is about 4 feet tall and pretty narrow.

We chose a place that will fill in the area for wildlife, and hide the fence which leads to a a neighbor's property. Last year we threw out our pre-cut Christmas tree. We didn't plant it, just left it for the wildlife, so obviously it died. It was a perfect fit for the area, so we'd like to replace that with the Blue spruce. It gets mostly shade, approximately 6 hours per day, especially in the summer when nearby trees have their leaves. The farmer said Blue spruce needs full sun, so that would not be an ideal location. I'm inclined to trust him, since this is what he has done for a living for over 30 years, but I'd like to hear from some of our experts as to the importance of full sun, and approximately how many hours a day it needs.

Update: I'm adding more pictures and information to address the comments and answers.

As I said, we'd like to replace the dead tree, which is just sitting there, and was never planted, with the Blue spruce. (In the top picture, it's to the left of the big tree, not the dead branch that's leaning against it on the right.)

Rather than try to calculate a dripline formula, I'll just report the trunk measurements and tree distances. All references to the trees are from looking at the picture from the front.

The big evergreen on the right is about 60 inches in diameter. The "dead tree" is about 15 feet to the left of that and back about a foot. A few feet to the left is a bush. Directly to the left is another tree, about 10 inches in diameter. To the left of that is another bush (azalea I think) that measures around 11 inches at the widest point and blooms in the spring and fall. To the left of that (about 15 total feet away from the dead tree) is a tall deciduous tree that's about 20 inches in diameter. Approximately another 5 feet to the left of that is the great big evergreen tree (Norway spruce?). That trunk measures about 70 inches in diameter.

My husband has now dug the hole right where the dead tree had been. It's 36" round and 24" deep, as we were instructed. He only had to break a few roots from the tree to the right. They were shallow and not too thick, hopefully not enough to damage that tree. There were also a lot of large rocks beneath the surface, which he took out.

Now that the hole is prepared, we're back to the question of how well a Blue spruce will thrive in that spot, and whether or not it's a threat to the health of the trees around it. Slow growing is fine with us. In fact, that was the original goal because we have no evergreens that are short or full, and we wanted something mid-sized. If possible, we'd like to keep it pruned to about 6 or 7 feet. We'd be fine about getting rid of the nearby bush, if there's a question of fighting for root space.

The first pictures are from last May-July when everything is in full foliage. It's dark and shaded there most of the day.

The second group was taken in December, a few weeks ago. The leaves from the deciduous trees have fallen, putting the tree in full sun for most of the day.

Click on pictures for closer views. These were taken between May and July:

This group was taken during the first week of December:

Answer 1

In my opinion, it is not a big deal. Six hours are enough. You can cut some branches of the other tree, and wait the spruce to grow, so it will get more sun.

In nature, young tree tend to grow in semi-shadows (most will die or be dormant also for decades in shadows, waiting a old tree to fall).

I just expect that it will grow very slow, but (also in my opinion) this is a nice feature.

Contrary of most deciduous plants, spruces don't tend to extend in order to find more light (thus giving a skinny form).

Answer 2

Blue spruces only need full sun to reach their top growth potential, they do not require it to be healthy. They will grow very well in shade, if they are not under another tree's dripline, and if there aren't many other tree roots in the soil.

Under a dripline, and in dense rooted ground, a spruce will grow much slower (sometimes less than 6" a year), and will perhaps not have the pencil straight trunk that is easy to achieve in full sun. Fertilizing can help with that.

In the shade, Blue spruces do not lose color, but the branching habit will tend to be lighter, more airy. And the tree may have a taller, thinner growth habit. I actually like to work with these better. Below are pictured some 15 year old blue spruce that only receive 3 hours of direct sun per day. They do, however, recieve dappled sun for some of the day as well, and the shade is light.

Answer 3

In the shade conifers do not do well. The only conifer that loves shade, does well in shade is the Yew. Conifers in the shade are stressed and regularly get the adelgid aphid and wooly aphid and it wreaks havoc. In the sun, Blue Colorado Spruce can get to 100 feet by 50 feet. In the shade it is even more susceptible to insect and disease. Looks so cute that contractors plant them next to the foundation routinely. Only to have to be cut down. Englemann spruce is very similar. In fact, most colorado blue spruce IS GREEN very similar to Englemann Spruce.

To have a living Conifer as a Christmas tree is more difficult than people understand. Are you using it outside to ornament or are you putting in a pot to bring inside and then be able to plant it back outside? Outside is one thing bringing inside can kill even a potted tree if it isn't acclimated step by step to survive inside for a few weeks then acclimated back to the outside before replanting.

People are kind of tricked to buy a live tree for Christmas without clear instruction on the acclimating process. (Oh my you just might have to buy ANOTHER tree)!!

I would keep what blue colorado spruce you have that are doing well outside, outside. I'd stop purchasing them and planting them. Fine for a cut Christmas tree but there are so many insects that rely on Englemann and Colorado Blue Spruce as part of their life cycle and cause major heartache for the tree and many other conifers such as White Pine.

Here is a simple list of common problems to watch your trees for; Spruce Beetle, Cooley's Spruce gall adelgid, Spruce Spider Mite, White Pine Weevils, White Pine Scale, Western Spruce Budworm, Douglas Fir Tussock Moth, Cytospora Canker. In all my years of maintenance of other people's landscapes I've never, not once ever found a Colorado Spruce without at least two or three of these insect populations.

Purchasing a great conifer for Christmas to plant in your yard is easiest if you chose a common conifer for your clime (where and what is that)? and purchase it already established in a pot. Do the acclimation thing for a couple of weeks, repeat the reverse acclimation thing after the holiday and plant in your garden/yard. Make sure you don't plant your tree too deeply. Only the root ball should be in the soil.

And Blue Spruce is a SPRUCE. Touch a spruce and you'll get poked. I prefer Fraser Fir. Loves high altitude and might not make it where ever you live. I've planted quite a few in lower elevations with proper watering instructions, raised out of the clay...and they did well. Tell the truth I don't remember ever planting Blue Colorado Spruce. Only Englemann. And only in proper environments. Too swamped with problems. Call backs make someone who lives off happy clients and successful plants very nervous. So I got to teach clients how to make both of us successful and happy.

Answer 4

Go for it! This location is absolutely a perfect place for Picea pungens!

I personally planted one last spring (and in a similar position to yours), and it endured unusually hot and dry summer extremely well, and looks nice and healthy. Needless to say that it can endure very low temperatures as well. Its natural habitat is high in mountains, and at the edge of forests. This means that, in nature, they do not get sun at least half a day, so no need to worry about sunlight.

It definitely has an uncanny magical feel. I spoke with several people that have this spruce, and all feel something special and misterious about it. It grows slowly, but you feel that it does grow. I heard that it doesn't like artificial fertilizers - basically you need only to water them during first few years, and infrequent but generous watering is the best. Pruning is best avoided altogether - only if you want to have denser crown, you need to pinch leader and main branches from time to time. And the rule is: do not remove lowest branches - the crown of this tree looks the best if it starts at the ground level.

I call it "The Queen of My Garden". When I transported it from the nursery, I put it in the passenger seat of my car, not in the trunk - the right treatment for The Queen! :)