The feeling of being overlooked in a garden is a major concern for some people. I have had clients who live in large properties that worry about a single covered dressing room window on a remote neighbour’s house facing nothing more intimate than their driveway. Others, mostly in urban environments, are often not bothered as long as someone isn’t staring at them at a close distance while they’re brushing their teeth.
Playing chicken- the psychology of privacy
Maybe the city dwellers have learnt to manage their expectations. Maybe they accept that in exchange for having to listen to their neighbours’ sneezes and worse, that neighbour will get an occasional glimpse of their pasty belly and pale legs on the rare occasion of a sunny day. They’re resigned to the fact that privacy in the urban context is the exception rather than an expectation.
I vividly remember living in an apartment in Los Angeles. Our windows were about 2m away from those of the neighbouring house, and I did not install any blinds at first so I would get maximum ventilation. That’s when I found out that other people kept their blinds closed permanently because they didn’t want me to look in!
Ever since, I’ve played (and won) that same game of chicken. I often remind clients who consider spending large amounts of money on mature trees to prevent a neighbour from looking down on them, that an upstairs window they’re worried about is likely a bedroom or a bathroom, both of which are private rooms where people do different things than look out during the day.

Boundaries rule and boundary rules
As a guideline, boundary structures other than planting must not exceed 2.1m. Any wall or fence (including trellis) that is higher is usually subject to planning permission. The tricky bit is where you start measuring the 2.1m if there’s a level change in the terrain either side of the fence. Nobody I’ve ever asked has been able to answer that question!
You can argue that if it’s your boundary then it’s going onto your land, so even if you neighbour is much lower, it would be hard to deny you the right to max out the height. Still, remember that good fences make good neighbours, so talk to yours when you’re working on your boundary – it goes a long way to maintaining a good relationship.
Now, I just said that planting is exempt from the 2.1m rule and I should qualify that: If you plant a leylandii hedge and let it grow out of control, your neighbours can sue you as just happened to a guy that let his hedge bolt to 26m! I wonder what the charge was – horticultural neglect? Antisocial behaviour? Let’s assume we’re looking at more modest screening, but something higher than your fence or wall, for which there are several options:
Hedging
This can be planted in front of or in lieu of your fence or wall. Mature hedging plants are not as expensive as you would expect and it’s an easy way of creating a green envelope, which is especially important if the boundary is visible from the house.
I usually default to evergreen, which gives me a bit more play with perennials in front of the hedge in the summer because I know the hedge will provide structure in the winter.
A note of warning: Avoid evergreens that don’t regenerate from old wood such as leylandii, which might be tempting because they are cheap and provide cover very fast. However, if you don’t prune them religiously, your hedge will turn into a monster you can’t fathom when you first plant those innocent little whips. It will happen before you know it, and any attempt to reduce its size after the fact leaves you with permanent gashes and a view of the plant’s dry brown guts.
There are plenty of fast-growing evergreens that don’t pose the problem above, so I recommend you look at Portuguese laurel, privet or yew for the basics. There is no shame in using a workhorse of a plant just because it’s ‘common’. It’s usually common because it’s not fussy to grow and maintain. There are many more options though so keep an open mind and research the useful information online hedging suppliers provide. Some of them are excellent and their prices often beat those of wholesale nurseries.
A note on biodiversity- I’m a contrarian here: Ecologists and councils take a hard line on non-native evergreens, and their horticultural xenophobia will prevail where they have a say on planting. I comply where I have to, but my view of diversity includes useful plants from around the world as long as they’ve been imported safely and aren’t invasive. Bees don’t turn down non-British pollen, and with so many plant diseases threatening native plants, I think we’d do well to broaden the range with robust alternatives. But I digress…

Hedges on stilts- Pleached trees
Pleached trees are shrubs or trees that have been grown to have a clear stem with a rectangular frame on top, onto which the branches are trained. The goal is to eventually grow a low-profile rectangular panel of leaves that hovers over the top of your boundary without cluttering the base. They’re nice if you need extra height above an attractive stone or brick wall, which can remain exposed between the stems. Pleached trees are at their best when their geometry and regular rhythm reads as part of the design. You can of course add climbers to the boundary behind- if you do so, a different shade of green
works best to avoid creating a monolithic ‘green wall’, and you’ll want to add shrubs and perennials or grasses to provide interest at the base.
Pleached trees are available with stem heights ranging from 1.8 to 3m, although a run of the latter would probably cost the same as an upgrade to a property that isn’t overlooked. Panel sizes are roughly 1.2m tall and 1.6m wide. The frames need to be removed at the right time, which is once the branch structure is self-supporting but before it’s locked in too much. And for that period, you’ll have to look at the frame.
Pleached trees have their place, but they are expensive and sometimes chosen as a default where a bit of creativity could have yielded a more interesting result. Definitely don’t get tempted to put them on even a small incline because you will have to step them, which looks goofy.
You also have to be careful of the side effects when creating a wholesale tall boundary with pleached trees because it impacts the amount of sun you get in the garden, especially in winter and in the evening, when the sun is low. And if your garden is small, the proportions of ground to boundary are important, so make sure you don’t end up with a private but very dark box of a garden.
Pleached trees are also maintenance intensive and can pose a challenge if you don’t have access from both sides to trim back the panel.
You need standards
A ‘standard’ tree that has a clear stem, like the pleached tree, but above that, the tree is allowed to do its thing and grow into its natural shape unless it’s been topiaried (i.e. pruned to a lolipop shape or similar).
Often, a good study of sightlines will reveal that only certain angles result in an ugly view or pose a privacy issue, in which case a single tree (or three) does the trick by interrupting that sightline. It’s a lower maintenance and more naturalistic solution than a tall hedge or pleached trees, and a variation in height around the boundary adds interest and blurs the perimeter.

Overhead screening
Some privacy situations or sunny locations require overhead screening. This can be achieved with a pergola, a sun sail, or with parasol trees. This describes the shape the trees are trained to rather than a particular species. It’s a niche thing, but easily found online and delivered by specialty nurseries.
If you go for a pergola, you might have one with lovers or a traditional one with climbers growing overhead. Its good to remember that even light and open planting provides screening from a distance. It’s a bit like a keyhole, you only see details through it if you get very close. And sometimes it’s the intangible feeling of enclosure rather than absolute privacy that makes us feel more comfortable in the garden.

Screaming and screening- Acoustics
This is a tricky one. There are expensive acoustic fencing products that promise a lot but don’t always do what you hope they would do- unless you build a little fort and surround yourself completely; and even then, it’s unpredictable where sound bounces off and just gets to you anyway.
Planting helps attenuate sound but works best for high pitched frequencies. For the remaining noise, masking and distracting is a good strategy. The sound of water is particularly helpful for this. Get yourself a water feature and let the trickle of the water wash over the traffic noise. And get some birds! Or rather, make your garden bird friendly and they’ll come. If all fails, turn up the music.

Ultimately, you will need to find the right balance of privacy, sun, noise budget, and maintenance hassle when choosing screening.