pruning albezia

I Just planted a small albezia tree (mimosa tree) and I would love it if I could get it to grow in that beautiful umbrella shape, sort of flat on top. It looks like it has been pruned to take an upright growth pattern but I was wondering if I should leave it as is and will it naturally return to the more flat topped shape or should I top it. I have never seen this look natural and would always avoid this kind of pruning...but? Any ideas?

I don't think you're supposed to prune them, they naturally get that umbrella shape as they get older. Most of the small ones that I see for sale at nurseries don't have the umbrella shape yet, I think that's something that comes when they get larger. I'm not sure what would happen if you prune it but it's probably better to leave it alone.

There is a tree down the street where they coppice the tree and it has always looked horrible. They shouldn't be pruned - they will naturally grow into an umbrella shape.

I know those trees have soft wood because they grow so fast. Don't plant it near your house! --Kris

I know I'm out of my region on this subject, but here goes: I wouldn't prune - the tree will do its natural thing, and it will grow quickly, providing some beauty. Having said that, I must tell you that it can be a noxious weed tree. Southerners love this tree, but I pull hundreds of mimosa seedlings every year, and I still can't control them. It is a short lived tree, so plant it in a place where it won't damage things around it. Since it grows so quickly, the limbs are not like a hardwood, but they can damage smaller plants near it. JEEEEEZ, I don't like being negative about any tree, but this is one that's like a bee in my ole' gardener's bonnet (well, in my case, a ball cap). Enjoy your tree. It's your property. LOL

Don't feel bad saying bad things about it--in addition to everything that's been mentioned it's also very invasive in some parts of the country, so plenty of people have lots of bad things to say about it! It's not on the invasive list (yet at least) out here, but every time I see one of these trees it's got babies growing up around it, so I would definitely keep an eye on it.

It will naturally get that shape. It doesn't matter if it's growing in your front yard, growing in the ditch, growing under the fence, or growing out of your foundation, they all look the same.

I've got a bee in my bonnet over Arum, so I understand.
Well thanks folks. Looks like I should leave it. That goes with my intuition. However, after closer observation it looks like it's been pruned already with one of the braches pruned unto a leader of sorts growing straight up. Hopefully this isn't permanent and the tree will revert to its natural form. I see them growing both in an upright form and as an umbrella shape. maybe these are two different species?I intentionally picked a fast grower. Grandma wanted a shade tree for the front yard and she's almost 90. It's got to get there fast so she can sit under it in her lifetime. I'm aware of it's invasive nature in some parts of the country, however, I don't believe the climate where I live is quite so friendly to it. I've observed one little tree struggling along for a couple of years now just down the street. Not growing fast at all. My guess is that our summers are too cool with too much fog (not enough sun) for it to really go, but I could be wrong. I see them growing around the neighborhoods and never see seedlings and haven't ever observed one growing in the green belts around town.

I think yours will still develop its umbrella form, that's how they naturally want to be and I've never seen a full grown one that wasn't umbrella shaped, so I think it's pretty hard to get it to do anything else. The more upright ones you're seeing are probably another type of tree--maybe a Jacaranda? Or some sort of Acacia? Those both grow around here and have similar looking leaves to the Albizia.