I think what the one response said covered it.

Dan

I don't mean to be difficult, but I'm not expecting perfection here. I definitely understand that the location is heavily constrained.

However, at the current state of the sugar maple, I'm only concerned about the height, and potential for much more growth. If I could just remove the top 10-15ft of the maple, the resulting asymmetric condition would be fine to me.

That's why I'm thinking that a 20-25 foot mature height tree would be alright in there. I'm not expecting a perfect specimin that you could get from an isolated location in a yard, just something that will work to fill the space reasonably well.

Dare I ask for a second opinion?

To clarify, you say your entry width is 12 ft.

o You don't want the tree to touch, so call it 9-10.

o But you have further constraints in that you can't presumably plant in the middle of the spot, further constraining limited choices.

o Nothing on the list is appropriate for that spot.

So.

o You need a columnar or fastigiate form of a tree that is adapted to the Front Range, a difficult climate.

o Butchering a plant to make it fit in a place it is not supposed to grow is not a good way to go (right tree, right place).

Good luck. Here is SelecTree. You don't need to fill everything. You do need to specify that you are likely in Sunset 2/USDA 5 climate zone, your pH slightly alkaline.

Dan

How about a Serviceberry -- Amelanchier? It can grow as a large shrub, small tree. I have trained mine as a tree and it appears that it will retain a narrow shape.

In this case, I think keeping it to size would be more "training" rather than "butchering". Once its shape is established, it should be ok on its own.

The spring bloom just ended here and it was delightful.

I have no idea about Colorado conditions.

Populus tremula 'Erecta' is a good one. I grew them in MN in a really tight spot. Also, Liriodendron tulipifera 'Arnold' is nice. It is zone 4 hardy.

I think a Swedish Aspen would work well there or a red baron crabapple both are really narrow trees.

Thanks for the suggestions - I'll talk those over with the local nursery to see if they've had success with those here.

Swedish Aspen would definitely NOT work well there - far too large and vigorous, with an invasive root system spreading up to 30 metres from the tree. Plant it, and expect serious damage to the foundations.

Resin

I didn't look at the photos of the site. The root issues can be very different in different locations. These (Swedish aspens) are used extensively in Canada and in the northern U.S. in small landscapes. I have seen 30 year old trees with 5 meters of foundations with no problems. On clay soils the problems with poplars is usually worse apparently. This is just my experience..

4 feet over from the bole you have a foundation and there's maybe 60-80 sf of surface area for planting and max 240 ft3 of rooting volume, more likely 160 ft3 if you're lucky. Not enough for a suckering tree like the Swedish aspen or a large tree like Liriodendron. Simply put, that building wasn't designed for a tree in that spot (I've been traveling and making presentations on fixing this very issue, BTW).

Nonetheless, I'd be surprised if Swedish aspen is on any tree lists on the Front Range. Don't know why, maybe I'll ask some muni foresters around here about it. We had a survey done recently on preferred trees and didn't show up on the LA or UF lists. Seems like it could be a decent short-lived tree in lawns...

Dan

Isn't the ginkgo biloba considered a well-behaved close-quarters tree?

Isn't the ginkgo biloba considered a well-behaved close-quarters tree?

It is, but those quarters are too close for even that tree. You'd have to limb it up 20ft off the ground when mature to make it work.

Dan

I 2nd Amelanchier(Juneberry, Shadblow, Service Berry, etc.) for that spot. Most won't grow much taller than the height of the building shown and most can be kept relatively narrow without a lot of pruning. They also develop multiple trunks and can be trimmed a bit narrow without having them look butchered. They can take the partial shading from the building as well. They have great spring flowers, nice tasty fruit(if you can beat the birds to it!), and great fall color not to mention nice smooth bark. Some will top out at about 10'(3m), while others will be more in the 25'(7.5m) to 30'(9m) range.

Also, Ginkgo biloba 'Fastigiata' mature width is about the same size as that width and could be kept a bit narrower with some pruning without too much hassle. It will grow much taller than the building though. So, I think it would work there too. I've seen some in the ground for about 30 years here in Kansas which aren't any wider than about 10'(3m) still. They are almost 50'(15m) tall though.

Well, after much agonizing, I've decided to go for a Montmerency Cherry tree. Here in the Front Range they're expected to grow about 15-20ft tall, 10-15ft wide, and have the flowers and green leaves we're looking for. Very cool irridescent copper bark while it's growing up as well. Hopefully the tree can learn to love it's little home!

Thanks for the help!

Hopefully, all of the birds won't make too much of a mess of your entryway.

The close proximity of the walls will allow you to easily attach bird netting to keep them away from your cherries and making an extra mess. Ensure you spray properly to ward off the blights and critters. You'll have yummy pies!

Dan

I have a couple of the arnold tulip poplars and I love them but they wouldn't be a good tree for that spot. They get to 15x70' and drops twigs regularly and the leaves would just blanket the home. That location needs an itty bitty tree.