Look, maybe the spruces work for you, or will for a couple of years yet. Especially with cars occasionally coming off the road at your house, I'm not going to be the one to suggest you take them down without having a good replacement plan. A wood fence doesn't offer the same kind of barrier as tree trunks 6 feet apart. Personally, as I said on the other thread, I would try to plant a replacement row and let it grow in a bit before taking down the spruces, even if it is city property. Depends on your municipality. But you make a good point about salt spray. I'm sure there is a right plant though. Or, you could take out every second spruce first and plant something new in between them, and then when those get big enough cut down the other spruces and fill in those holes. It could even be new spruces, you've got one new one in with the big ones now anyway. So your barrier would be in a state of perpetual renewal and never entirely gone, not the worst thing. But your priority seems to be to make use of the backyard. I have to admit I don't understand this, given that you have a huge yard in the front that is probably quieter and safer. Maybe it's that your house is organized for easy exit to the back and not the front? Or you'd rather be closer to the road to get privacy from the neighbours? As for a structure, it can be as reliable and strong as you make it. If you buy a pre-fab from Canadian Tire or your local equivalent, it will obviously blow away unless you pack it away every winter. But if you sink some serious posts seriously deep and build the rest out of serious dimensional lumber with good joinery, it could be as solid as a house. By the way I think you'll always be cutting those trees down, not selling or moving them. They're common and fast-growing trees so I don't think anyone would have to go to the trouble of trying to dig them out. KarinL

Thanks, Judy and esh! Actually, Judy, the Sambucus does receive a fair amount of sun in the morning and early afternoon. So it is still considered a full sun location. It is actually quite a few feet away from the tree trunk, but the photo makes it look closer than it is!:-) I think that this location is OK for water etc. because the grass was quite green around there even before I planted the Sambucus. Now that I water it frequently, the grass is even greener! LOL Esh, did you read my mind!? :-) I just started planting these shrubs around the trees since last year. Finally (perhaps this fall?) I will covert this entire area to be a flower bed, and then I will put in different colorful perennials around these shrubs. I am glad to hear that yours is like mine too - it's very reassuring! Thank you!

Roots go out, not down and yes, those roots grow wide. There is often a comparison to the root spread diameter to twice the height of the tree, but that is not hard and fast. Sometimes they will be more restricted and at other times could spread much wider - it is all in response to nutrients and moisture availability. And to any obstructions in their path. Thuja plicata, western red cedar, is native to the PNW and there are many very venerable and very large specimens in gardens all over, even in the heart of the city. As they age, they often produce a quantity of large surface roots, to the bane of many lawnmowers :-) As ken noted, roots are not a threat to a stable and secure foundation, especially in most of the PNW where soil subsidence is not an issue. They can and do lift slabs and patios or driveways, however.

In addition to potential root damage, consider the mature width of the plants. If the Cercocarpus gets wider than 12 at maturity then you will have to prune it to keep it away from the house and that will affect it's shape. More work for you and not so good for the plant either. So research the mature width and divide by two - that would be the distance from the house at a minimum. If 10 feet, then divided by 2 equals 5 feet and therefore planting it six feet away is ok.