Screening

the x Cupressocyparis leylandii is the best tree they can push 1 M by year but need to prune 2,3 time in the year i think you won't find a tree more vigorous

Alexandre is right - if you do decide on leylandii, keep pruning! You have been warned! LOL.

There are about 200 greens out there. Do you want to look at only greens, as you will. Maintenance is in constant need as Spritz and Alexandre have already said.
Deep shade will swamp anything in front of it.
Would it be possible for you to have Trellis put up, which is instant and then choose something with colour to look at, i.e. Clematis Armandi, Jasminum Officinale, or Passiflora Caerules.

i wouldnt they have a spread of about 25` and maybe 50` tall.you aer aloud to put trellis up on top of your 6` or what ever hieght fence you have.virginia creeper would fill the gap well.perhaps go to a garden centre and buy some bigger size nicer trees with instant effect

no real pruning either

Would I have to prune the Leylandii - or could I just let it/them grow and grow? There is a grassy walkway (but wide enough for cars) between my fence and my neighbours so the trees would be about 15 feet from their gardens.
I did think about trellis on top of the fence but it is about 100ft long, so I think it would be very expensive. Maybe Russian Vine - but I guess that too would need the trellis for it to achieve any real height.Thank you for pointing out the shade element, my little pond is close to where the trees would be.

Hi Ginellie,
The cost of Leylandii in this area ( I see you are in Surrey) would outstrip the cost of the trellis and climbing plants.
You could let the Leylandii grow as you said but you may have trouble with height restrictions.
Where are you in Surrey?.

You have some sound advice here Ginelle. If you would like to see some screening I have several examples which are very unusual. My garden is near Tilford in surrey. You are welcome to see it on condition you bring your King Charles cavalier as well. I just lost mine.
Rod

Another option would be bamboo, might be pricey to fill the space you want to, but if you are careful to choose one that does not runner, would be less maitence than Leylandii. there may be other options too, you could go for any number of evergreen shrubs/trees, or a selection of different ones to give texture and interest, just some i can think of would be Holly, Laurel, Ceonothus, Photinia, but these wont give the same sort of hieght that a fully grown Leylandii will give, but if it really big that you want, i would advise having a chat with Bluespruce, he is the best one to advise you on Leylandii, and other options which may better suit your cause.

You might also have hassle with neighbours complaining if you just left the leylandii to grow without pruning them. There are so many disputes about these trees - please be careful - and think hard before you go ahead!

Having, in the past, planted 65 leylandii trees in a hedge - beware! It grew to 15 feet in height in 7 years and nothing grew at its base. It became leggy and some plants looked as though they might die. We chopped it down to half height and then quickly realised it had to go.

I agree with Majeekahead. Bamboos, chosen wisely, are fabulous. We are going to put more in our side border - they are evergreen, and we strip off the side shoots to appreciate their stems. It's great to hear the breeze flowing through the leaves.

You can tell how thick a stem (culm) will be as it comes out of the ground - we prune out the weak stems. One stem shot up 19 feet in 6 weeks! We feed them with chicken manure, Growmore or lawn feed. You can see them in some of our photos.

laylandi now need planning permission i believe

get strong buckets cut the bottom out and bury them.plant bamboo that runs.it sends suckers just under or on the serfice .as the whole earth isholding it back it will have trouble splitting the bucket.also as buckets tend to slope out so ne suckers will always go up.another top tip

There is now a Golden Leylandii called Gold Ryder. It grows at about two thirds speed of Leylandii proper. Check it out at your Garden Centre.

Yes, the old Leylandii situation, this is certainly a bone of contention on the web and elsewhere.
It can be a useful screen mainly from the fact that it gows rapidly and if you are not willing to wait too long then perhaps this is a fit but unfortunately I have seen large unpruned trees blown over in some instances and it would probably be better to maintain the height and width somewhat.
A pruning/shaping tip:if you have the base tapering ie the base wider than the top then it will stay thicker at the bottom as it will receive more light and also should shed snowload better too.
Here are some other options which I have tried and tested;

x Cupresocyparis leylandii 'Goldconda'
" " 'Golden Rider'
Thuya plicata 'Excelsa'
Tsuga heterophylla (Iknow can be slow to reach a good height but really makes a classy dense hedge)
Tsuga canadensis
Taxus baccata and many of its cultivars eg HIcksii', 'Melford'. 'HM Eddie" I appreciate how Yew can be pruned hard and will happily come back.
Chamaecyparis nootkatensis
Cupressus macrocarpa 'Donard Gold' Gorgeous but check it is adequately hardy for your area.

Broadleaved evergreens:

Prunus lusitanica
" " 'Variegata'
Elaegnus pungens 'Maculata'
" x ebbingei 'Gilt Edge'
Arbutus unedo

Hope this is helpful, sorry for the long message.

Podocarp

Thanks to everyone who commented on my Leylandii question and gave such helpful advice.
When I finally get a digital camera I can take photographs of the garden as it is now, rather than with my present camera which involves taking the films to Boots - often 6 months after I took the photographs - and getting everything put on discs.How old fashioned is that!

~ what about Griselinia?