Ivana, That tree is part of the pea tree family. Unfortunately Alberta is a zone 2 area. Pea trees are borderline in zone 4. It's also has some nasty thorns. There may be some microclimates that could sustain these trees but that's risky. You may get good growth for some years but it takes just one severe winter and the tree doesn't survive. In fact all trees of the pea tree group are not hardy enough in zone 2.

I'm afraid I cannot think of another tree that looks similar to black locust.

Maackia amurensis is also in the Pea family, is zone 3 hardy, and has white flowers and pinnate leaves like Robinia. Flowers are fragrant (like R. pseudoacacia) but held erect. Overall habit is less Acacia which is a nice feature of R. pseudoacacia when it's mature.

O.K. Here's my two cents worth. I know my zone is a lot different than yours, I'm in zone 5a, but we grow several of the native black locust. I consider gardening here somewhat similar to growing on the prairies, we have heavy clay and in the winters we get gale force winds. We have lost about 6 crabapples due to that but the locust seem to do fine. My advice would be to get a native black locust and try that one. I started mine from seeds, they take well to winter sowing. Are you in town? If so and you say you want to plant it in your backyard, then it will have some protection from the elements. If you want to further protect it, mulch it well in the fall. If I were in your position, I would start one from seed and go ahead try it. Marg

I bought a 'purple robe' r. pseudoacacia last year, and it overwintered here with no winterkill. It's just leafing out now, and I had to do a number of bark tests in the spring just to assure myself it hadnt' died, but all seems to be well now. I live in Peace River, and if it survived here, you may as well give it a shot where you are. And just in case you think this is a fluke, I should add that I have a ginkgo in my front yard (and doing very nicely) and some other 'exotics' as well.

Mine flowered the two weeks of June this year; here's a picture of it.

Ohhh! I didn't realize you could get them with pink flowers. Those are really nice. I'll have to look at getting some. Marg

davidcalgary29 ... those blooms on 'Purple Robe' look great! Friends of mine in Edmonton had purchased two of these trees from Home Depot and for several years they performed very well and the folks were very enthusiastic about the blooms and foliage. Though, unfortunately, even after nicely establishing themselves, the trees both died back severely and then were completely dead the following spring. These specimens had been planted in an exposed location with the full brunt of the north and west winds. On the other hand, I live in an elevated location outside of Edmonton and with a very protected back yard and seldom ever experience temperatures any lower than what is recorded in downtown Edmonton ... so, I'm thinking I would have a good chance with this tree if I could obtain it.

Terrance

"Purple Robe" is a very interesting tree.... Had for a few years and it would get bigger and flower beautifully every June. It died completely to the ground in 2011. I have a sneaking suspicion that the -25c or so that we got in Edmonton in November 2010 did it in as it was still actively growing. This tree grows even in October and I dont think it hardens off properly. Here is a pic of it in summer 2010. I am now overrun with suckers from this tree....

{{gwi:530519}}

Andres, yes, in the autumn of 2010, severe sharp cold dropped out of the arctic before some of the trees had ripened off, I think that was the year the leaves had been freeze dried on many of them.

Your 'Purple Robe' was a beautiful tree, really too bad for its loss.

This tree's weedy nature certainly is a double-edged sword! I've found (and even in Ontario, where I used to live), that Black Locust is very prone to structural damage, but its continual growth often compensates for winterkill, and leaf loss from powdery mildew and insect attacks. I fully expect to lose half the tree (or more) this winter, as I'm in such a marginal climate zone. I'm hoping that stable winter temps (no freeze-thaw cycles up here!) and a protected location will help.