Help! Shrub for narrow strip between drives

Hello, I need some ideas! Our neighbours just replaced their lovely lawn and trees with a large expanse of block paving, it's smart and I rather like it, but it is a bit stark. We have 1m wide strip of land separating our drives, presently it contains a small tree (lilac) and a row of big round box hedge plants. I'm going to reduce the width of these box plants so that in between can plant some new, taller plants.

But what?!

I need something that will grow up like a tree but doesnt have big roots (don't want to damage the neighbours block paving). I was thinking buddleia might do the job but my mum says it won't. Then I thought a tree form of ceanothus, but not sure if you can buy these.

What other plants could I use? Would love some ideas!

 

Hi @MrsRake I think the problem is that the size of the root ball is normally matched with the size of the top growth - in other words, the amount of roots needed to get water to a big plant is bigger also. You probably need to look for something with fibrous roots so they don't heave the paving - and apart from rhododendrons and camellias I can't think of anything. Bamboo would be too invasive, and proper trees (as opposed to buddleja which is really a shrub with ambitions) tend to have big solid roots. Maybe grafted small crab apples like floribunda or profusion which are blobs on sticks rather than low blobs like your box?