Even the iris flowers  & tree stem colours match the timber!*

Having a pergola, arch or planting rail in the garden can be a very nice feature as it adds height and year-round interest. However, it is critical that they are correctly situated otherwise it could end up looking out of place and a bit of an eyesore!


As wonderful as a pergola or arch can look, they certainly don’t suit every type of garden, so how can you tell if it will work well for yours?

Before we look at the where of pergola placement, we need to cover the why. If you get the why part right, then it will help you place the pergola properly.

So why do you want a pergola in the first place?

  • Is it to help screen the neighbours from viewing directly into the garden?
  • Is your garden flatter than the proverbial pancake and you want to create some height and interest?
  • Or, perhaps, you just really fancy the idea of having a pergola and don’t have a specific problem to solve?

Anything you place in the garden has to have a purpose, even if it’s just a visual one and never actually gets used. So if you chose the last option, be very careful to make sure your desired pergola actually works with the rest of your garden.

How to correctly place a pergola

You need to think, first and foremost, of a pergola as a path. Completely ignore the fact that it has upright posts and roof like cross beams. Just think path. Now ask yourself, would you put a path to the location that you are planning for the pergola? Would it look right? Or would you be thinking, why on earth would I have a path there!


Things making sense visually is critical, as I mentioned earlier. A pergola is really a fancy walkway, so it needs to go to and from somewhere in order to make sense.

If it doesn’t initially make sense, don’t worry, there are things you can do. If a walkway style of pergola doesn’t seem to work, then consider a corner one instead, as shown in the example gardens below.

A corner pergola also works well in small gardens as it doesn’t take up too much space. The other alternative to a corner pergola is one that juts out from the house, usually over the patio doors. If you choose the latter option do be careful about how much light it will block out, especially when it’s covered with plants.


So, if the pergola doesn’t form a specific function, i.e. it’s not really needed to add height as you already have trees or it won’t work as a path and you don’t require shade over a seating area, then I would suggest you don’t go for one.

I certainly don’t use pergolas in every garden I design – I probably only put them in 25% of the gardens I design, because they are not needed.

Pergola materials and styles

Timber-PergolaThe material types and sizes you choose for your garden pergola will have an enormous impact on how it will look. It’s really, really critical to get the right materials and especially the right size of materials in order for the pergola to look right.

A pergola needs to look good even if it’s not covered in plants. Whilst plants will hide a multitude of sins, they do take quite a while to become established and unless you’ve chosen evergreens, you’ll see everything in the winter months. So let’s make sure you get it right, so you don’t have to wait years for the plants to cover it up!

How to get the right size pergola for your garden

In order for a pergola to look good, it has to be both the right width and height. The right height is fairly easy, approximately 7ft high (2.1 m) is a good starting point. Pergolas can certainly be higher than that, but they shouldn’t really be any lower.

A 7ft high pergola allows someone that’s under six-foot tall to comfortably walk under it without feeling like they need to duck their head down. It also allows the plants to hang down a little bit. Obviously, if you are taller than six-foot (1.80m) then the pergola definitely needs to be higher.

It’s important to get the correct width to height ratio

When it comes to having the right width pergola, that gets a little bit trickier.

If your pergola is 7 ft high and you have a path underneath it that is 2 ft wide, then if you were to put the pergola posts at 3 ft apart (1 m) that might sound about right, unfortunately, it won’t look right.

Having the posts that close together will make the pergola look very tall and skinny. So visually, in order to look right, the posts would need to be at least 4 – 5 ft apart, width-wise.

If you require a pergola that is over 7 ft tall, then you’d need even more width, to make sure it looked right.

Also, the larger the pergola both in height and width, the chunkier the materials need to be, in order for it to look right. So if you want a really wide pergola then brick pillars or really big bits of wood would be required.

Now we’ve covered the height and width, what about the length?

Thankfully, when it comes to the length of a pergola, you have a lot more flexibility and freedom. It can be as long or short as you need it to be to suit your situation.

Also, the spacing between the posts or pillars for the length can be different from the width. Unless you are planning on an L-shaped pergola, then they do need to be equal so that the corner works. So, for example, you can have a pergola that is 5 ft wide with the posts for the length every 6-8 feet apart etc.

Choosing the right top for your pergola

Just to add to your array of choices, the timber you use for the top of your pergola can be, and often is, a completely different size to the timbers you use for the rest of it. Again, a lot of the choice comes down to the overall size of the pergola. The bigger it is, the larger the top sections of timber or metal need to be. It tends to look better to use wider but narrower sections of wood for the top to the posts.

Pergola example using 4 x 4″ posts with 6 x 2″ tops

A combination I use quite a lot for medium-sized pergolas is 4 x 4″ posts with 6 x 2″ tops. For small gardens, I use 3 x 3″ posts with 4 x 2″ tops. For larger gardens, 6 x 6″ posts and 8 x 2″ tops work well.

Pergola styling

Yes, there’s more! It doesn’t just end with choosing the right size pieces of timber, brick, metal or whatever materials you’ve chosen to construct your pergola from. The real detail to pergolas comes in how you finish the ends.

It’s the ends of the timbers used on the top of the pergola that dictates, often more than anything, the overall style of it. Your choice of the end will make the difference between the pergola looking very traditional or modern, as shown in the examples below. Basically, the more ornate the end, the more traditional the pergola will look.

Pergola timber ends from traditional to modern and contemporary with no end at all!

What material should you use to build your pergola from?

The choice of materials comes down to your tastes, but probably more likely budget. As wonderful as the traditional round stone pergola pillars with ornate metal tops look, in reality, that style pergola does cost a small fortune. So timber is usually the most popular option because it’s the most affordable.


Of course, you can do a combination of brick and timber, but as soon as you are using brick or stone, then the costs do escalate dramatically.

It takes a lot of skill to build a brick pillar pergola because of the time it takes to line up all of the pillars correctly. If a single pillar is slightly out of alignment or skewed at an angle it will throw the entire pergola off and really show up when the top is put on.

I bet you never knew how complex a simple pergola could be! I must admit, I hadn’t realised how much there is to think about until I wrote this. At least it explains why I spend so much time on them when I do put one in a design.

Garden pergola examples

Here’s a selection of pergolas that I have come across on my travels.

Metal pergolas from Agriframe


The very traditional stone pillar with timber and metal tops from gardens in Granada and Madrid, Spain.

Finally, a selection of timber-framed pergolas from Spanish and UK gardens.

Timber pergolas

Sometimes an arch is better than a pergola…

My final choice to add some height and interest and help frame a view down the garden is putting in an arch. Just like pergolas, there is a choice of styles and materials to choose from.

Metal garden arches from Agriframe

More pergola alternatives

Now, if you’re still unsure if a pergola is right for your garden, or you are concerned about the costs, then there is another option available to you. Planting rails can look incredibly effective in the right settings.

Think of planting rails as the pergola’s smaller sister…


So what exactly is a planting rail?

Basically, it’s like a pergola, but it’s like a flat version that you can either put across the garden or on top of the fences to add a bit of height and dimension to it, as shown in the photographs above.

The main purpose of a planting rail is to add height. So you can use them on top of an existing fence as a way to grow climbers higher than the fence and help screen the neighbours.

The other use of a planting rail is to frame the view as well as add height. This happens when you use them across the garden. Placement, however, just like it is with pergolas, is critical if you’re going across the garden.

Chelsea Flower Show Garden

How to correctly place a planting rail

There’s no exact rule here, but visually, I think it looks better if the planting rail is at the beginning or end of the garden rather than in the middle. You can see in our example garden above that the planting rail framed the view to the top raised patio at the end of the garden. So it wasn’t just floating in the middle of nowhere, it linked in with the patio area.


You can also use a planting rail a bit like an extended arch, with sections of trellis beneath the rail. This gives you a more solid division in the garden than the example garden version. So just imagine that garden with each end of the planting rail filled in with trellis, making the patio area a bit more enclosed.

Another way of using a planting rail is to have them in raised planters. That way you create interest and height and a place for climbers to grow up out of the planters. So as you can see, there are many uses for the underused planting rail.

The other advantage of the planting rail is that it’s obviously considerably cheaper to install than a full-size pergola. You can use metal or timber, the choice is yours. Obviously metal you can bend and shape more easily, so that gives you greater flexibility with your styling, but of course, the metal will be considerably more expensive than timber.


BUT do be warned, a nice arch or pergola will NOT give you a stunning garden – you have to get the design layout right first. If you don’t know how to do that then…

Attend one of our FREE Fast Track Garden Design online classes…

Register on this page: https://www.successfulgardendesign.com/free-classes/

*Photo Credit: top photo the wonderful Herry Lawson

*Photo Credit: Chelsea Flower Show Garden & maroon pergola – the creative Karen Roe



Rachel Mathews
Rachel Mathews

Professional international garden designer for over 30 years. My mission is to de-mystify garden design and make it easy for people to successfully design their own garden - without needing to spend a fortune!

    5 replies to "Pergolas, arches & planting rails"

    • Larysa Zynyuk

      How about pergola as a connection point between some parts of the garden?

    • Georgina Scalise

      Hi Rachel! how about a pergola in the patio next to the house? Thanks!

    • Successful Garden Design

      Hi Larysa, yes that works as it frames the view (assuming that there are things either side of the pergola) so if it's the type of space that could visually take a gate (even if you wouldn't actually want one), then a pergola would work as it frames the view.

      If however, the gate would be all on it's own with nothing either side, it would look silly and so would a pergola – hope that helps and hasn't made it more confusing!!

    • Successful Garden Design

      Hi Georgina, Yes that can work, provided it doesn't shade the house too much. Visually it looks good as it looks like an extension of the house. Pergolas don't look right when they are in an odd place away from everything else. As long as they serve a purpose then they look right.

    • Helen Hill

      We built a square sunken seating area with gabion seating, a fire pit in the centre, large square planters in the four corners and a pergola over the top. It’s a great party space and the climbers are getting established over the pergola, softening the whole thing. We love it.

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