To be concerned about leylandii hedge newly planted right next to boundary.

[Marcellos]

I can’t do anything about it can I?

AIBU to be worried about it getting really wide onto our side and tall?

Cut back anything that grows over

If it does, you can trim it from your side, I think

You can cut back any branches that overhang your boundary. I think there’s also restrictions about how high they are allowed to be grown.

On the plus side, privacy and greenery!

I’m of the opinion that leylandii should be banned from sale in this country. They’re awful antisocial trees, for both us and our wildlife and they really have no place in this country’s tiny gardens.

there’s probably nothing you can do other than have a conversation with your neighbour about keeping them at a decent height.

If they've planted the saplings right on the border then they'll definitely encroach on your space as they can grow quite wide. You'll need to keep them well trimmed on your side and hope the neighbours keep them at a sensible height.

How close to your house are they? Eventually the roots will be longer than the trees are tall and could cause problems with foundations, either sapping all the groundwater or infiltrating.
I'd question it now with the neighbours if they're close to your buildings. Too late once they've shot up.

They're a stupid choice of hedging, very unneighbourly

If they block the light to your house, surely you have a case then?

You are right to be worried - we are bordered by 2 neighbours who have/had it growing on the boundary. The 1 hedge we are forever cutting back -the maintenance is unreal and the neighbour is happy for it to grow wildly over everyone else’s garden and just keeps her side neat and tidy with obsessive trimming her side. All great, but we never signed up for having to maintain a bloody hedge!
The other neighbour had just one and let it grow so big that all of its branches were touching our house. It completely took over. They eventually cut it down to nothing, but we had to put up with years of it encroaching before that happened.

I have it in my garden (my hedge unfortunately - came with the house). I hate it - can't afford to get it pulled out and replaced with a fence and it's really hard to keep at a decent height. If you cut it too much it looks even worse than normal!
The only good thing is that it does give privacy.

You can’t do anything about the possibility that a plant might one day grow larger if it isn’t actually currently a problem.

Is it definitely a Leylandii ?

Yes you can trim it , but you will need to get rid of the branches . Law states you need to "offer the branches to your neighbour" but are they going to take them ?
You cannot chuck them over the fence - fly tipping .

You can say to your neighbour "I hope you'll keep this hedge trimmed . I could cut my side but I'm not a great gardener I'd probably mangle it and kill it . HaHa"

Isn’t that your fault for not having anything keeping your boundary on any side though?
If you wanted you could put a fence up.

We have a wall right around our boundary 5ft high! I think you are underestimating the height these trees/hedges get to and how they spread out once they reach a certain height!

Edited to add - the neighbours hedge is around 10 ft high and the neighbours tree version was taller than our house.

my neighbours ones are higher than his house including the roof (semi detached house with the usual pointy roof). so it must be over 30 feet high. itll cost a fortune to cut as he will need specialists.

i’d suggest keeping it to 7 feet high to make it possible to cut himself but it’s too bloody late now.

and they say the roots fan out to the same height as the trees and more so his must be well over 30feet long and now under my property….