Written by davethetreecenters • September 21 Spacing Hedges – Let’s Get it Right

Hedges are important components in just about every garden. In cities and suburbs they give privacy and a calm background to your garden, screening out neighbors, traffic noise, and unsightly views. In rural areas they provide wind protection and that sense of enclosure that is often needed when creating a garden inside a larger area. While hedges are often planted around the perimeter of a garden, to define its overall form, they are also incredibly valuable as internal dividers, especially in a large garden, where they can separate work areas from ornamental sections, and enclose the vegetable and fruit areas from lawns and play sections. Low hedges can border drives and pathways, and although they are often thought of as straight and formal, they can also curve and flow gracefully for less formal looks, and be used playfully too, with undulating tops, or even trimmed into exotic forms, like the 100-foot dragon hedge shown at the top.

Correct Spacing is Vital

Whatever the form or function of your hedge, and whether you choose evergreen or deciduous plants, spacing out those plants correctly for your needs is vital. Too close and you will have an overgrown mess that will quickly thin out at the bottom – besides costing you more than it should to plant. Too far apart and that smooth, flat surface you want could be decades away. Hedges should be the first thing you install in your garden, once you have decided on the basic layout, so let’s take a detailed look at this issue, which always creates uncertainty for new gardeners.

One Row or Two?

There are two basic layout patterns used for hedge planting. The most common and straightforward is to use a single row of plants, evenly spaced along a line. Remember when doing this that the first and last plant should be half the spacing distance away from where you want the hedge to end, which could be in the open, with a trimmed end, or up against a wall or fence. A common mistake is to plant the first tree right at the end, forgetting to allow room for foliage to develop and make a smooth, green edge. Always use a tight cord to make the line, and space out all the plants before you start putting them in. That way, any slight errors in your measurements can be adjusted for by moving plants around a little until you are satisfied that they are all evenly spaced. If the spacing you use is relatively close, then digging a trench for planting will make spacing much easier and give your new plants a great area of dug soil to spread out into as well.

If you want a really dense hedge, with maximum sound buffering and wind resistance, then a double row is the way to go. The rows are staggered – that is, each plant in one row is in the space between the plants in the other row – a kind of zigzag pattern. You do of course need more width, so this option is rarely useful in a smaller garden, but for a big windbreak hedge it will give you quick results and a solid fill.

Spacing Distances for Single Rows

The distance apart you space your plants depends on two factors – final height and the natural width of your chosen plant. For low hedges you obviously need the plants closer together, and for something like a 12-inch boxwood hedge, planting as close as 8 inches apart is normal. For that you need a supply of small plants, but most hedges can be successfully created out of larger material, of course. As a general rule, with smaller plants and hedges under 5 feet tall, the spacing should be about two-thirds of the intended finished height of your hedge. So, if you want a 3-foot hedge, space the plants no more than 2 feet apart. As well, when planting low hedges, choose rounded or bushy varieties of the plant, not slender upright versions. This sounds counter-intuitive but keeping low hedges bushy all the way to the ground is often an issue, so you want plants that push shoots out sideways, not straight up.

Consider too the final height of the plant you are choosing, and its growth rate. It is easy to see that a plant that normally grows to no more than 3 feet will never make a 5-foot hedge. However, a plant listed as reaching 10 feet, but that only grows a few inches a year, like some boxwoods, is going to take a couple of decades to reach that 10 feet, which is rarely a practical time-frame when growing hedges.

For larger hedges the key factor is the natural width of the plant. Try to find its height and width after 10 years of growth. Will it be tall enough by then for the hedge-height you want? Look at the width. That represents the growth on both sides of the trunk, so its sideways reach towards another plant is half that. Two plants side-by-side will, if spaced that width apart, touch after 10 years. However close planting makes bushes grow upwards towards the light, so they will be slimmer. A good rule is to space your plants at half that ‘10-year width’ apart. So, plants that will be 6 feet wide in 10 years should be spaced 3 feet apart in the row.

Spacing Distances for Double Rows

A double row isn’t just two single rows, staggered. That will be too crowded, and the plants will grow tall and spindly. Calculate the spacing for a single row, and use that as the spacing between the two rows. Add 50% to that single-row spacing, and that is the distance apart for the plants in the row. If you do the math – we won’t bore you with it, but remember that Pythagoras guy? – that creates a situation where the spacing on the diagonal is 25% more than the spacing for a single row. That gives us a good alternative way to lay out the plants, using a stick cut to the single row spacing plus a quarter of that spacing. Place it at 45 degrees to the direction you are going with your hedge.

To Summarize

All that sounds a bit complex, but it isn’t really. Let’s summarize:

Find the width and height your chosen plant should be after 10 years of healthy growth
The planned height of your hedge should be no more than three-quarters of that height. A plant that will be 10 feet tall after 10 years is a good choice for a 6 to 7-foot hedge.
The spacing apart should be half of the 10-year width, or a bit more if you aren’t in a hurry. If that width is 6 feet, then space the plants 3 feet apart.
For hedges under 5 feet tall, use instead a spacing that is two-thirds of the intended height. For a 3-foot hedge, space your plants 2 feet apart.
For double rows, the spacing on the diagonal is 25% more than the spacing that would be used for a single row. If that was 4 feet, then the diagonal spacing should be 5 feet.

See, that was easy!

Comments 6 comments

March 27, 2021 by Martha Rudd

Very informative! And a formula I can use for any of my chosen hedge plants. Thanks.
April 12, 2022 by Joshua

I planted 10 five foot tall Nellie R Stevens Holly’s 6 feet apart for a hedge as a living fence. I don’t understand spacing fully. I hope they grow 20 feet tall but stay full for a privacy hedge. I don’t plan on ever pruning. Are they too close? Should they be 8 feet apart or more?

April 12, 2022 by davethetreecenter

Well, considering that 10 to 12 feet is the expected width of a mature Nellie Stevens, 8 feet would be better. But if they have been in a while you are probably better not disturbing them. The danger with planting too close is that they don’t fill out well, because they are struggling to grow up for the light – so close planting can be counter-productive. You could solve that by doing some trimming while they are young, sloping the sides inwards to let light reach the lower branches so they really thicken up. It’s actually impossible to expect them to reach 20 feet and stay green to the ground without regular trimming – twice a year when young, once a year after that. Untrimmed they will develop clean trunks for, what, 6 feet up, within 10 or 15 years. Wider spacing will extend that time period, but it will still come one day, as the upper crown spreads out and shades the lower areas.

September 5, 2023 by Stewart Gray

Fantastic – you give the HOW and explain the WHY clearly and concisely – Thank you.
October 21, 2023 by William Lockhart

I only have smallish front and rear gardens, 5x 5 and 12 x 3.5
I want to create patches of double rowed hedging for wildlife mixed plys allow some trees to be trees to provide some shade in the garden. The plan is to coppice and pollard the trees and hedges to keep everything smallish due to space restrictions. I’ve bought the typical Rowan, Blackthorn, maple, wild pear selections of trees. I want around 6ft to 10ft high hedge and the trees can get to double that but I don’t want them getting too big.

3 ft between the hedging trees is okay? And 3ft space between the two rows?

Maybe in small gardens a double row is not going to work?

I already have 6ft fench panels around rear garden. The front garden is open but has a large pine in one corner taking all the water and sun . I can send pics. Any ideas on the overall design would be useful.

October 21, 2023 by davethetreecenter

Well, right away I will say you are right, in small gardens double row hedging isn’t going to work – it’s for big areas only. You have such tiny areas to work with (I assume your dimensions are in feet), that personally I wouldn’t go with hedging at all. Secondly, if you pollard those trees, you won’t see any fruit, so besides offering some shelter and maybe nesting sites, it’s value to wildlife is going to be limited. Any bushy green plants offer birds shelter and nesting site, although they can be choosy about what they will nest in, or not.
Can I suggest you do a to-scale drawing, not horizontal, but looking at in in cross-section, of these spaces. Do you really want a 10 foot hedge around a garden 5 ft by 5 ft?,or even around the larger one, which in fact is not even double the surface area of the smaller one, and extremely narrow? Since you already have the pine tree, (which through its cones is providing significant natural food already), I suggest you don’t need anymore trees in that space at all. Although a little easier to plant under than denser evergreens, growing plants beneath a pine is difficult to impossible. It isn’t just the shade and water reduction, but the sterility of the soil they create by taking up most of the available nutrients. Have you considered growing plants there is pots? With automatic irrigation systems, if you use them and maintain them properly, and also supplement them with hand-watering (or just rely on hand-watering entirely), then you could have a nice, open look in that area. Choose shade tolerant plants, using pots, trying for things that will be effective across several seasons, and keeping it simple, would be my favored approach, certainly in the area with the existing pine tree.
You don’t mention your zone, or if the pine is in the larger or smaller space. Remember when choosing plants for pots that will be outdoors all winter, you need to add 2 hardiness zones – so for zone 6 you need plants hardy to zone 4, for example.
Personally, faced with your situation, and already having those panels, I would go with espalier – growing most of the plants by planting right at the foot of the panels and then spreading out and tying in the branches to the panels. That way you get a green wall effect, without taking up precious space in the area. That way too, if you want to work with the existing plants it seems you already have, you also will be doing a lot less trimming, and so will have a better chance of seeing flowers and fruit. Pruning would consist of shortening back the branches that grow from the permanent framework that is tied to the walls, and that encouraged the formation of what are called ‘spurs’ – short permanent branches that produce leaves, flowers and fruit.
As for your need for shade in the area that doesn’t have the pine tree, buy a nice umbrella for the summer, and enjoy the flood of sun the rest of the year – the plants will thank you too for that, because none of those you have will grow in the self-induced shade they will create for themselves and you.
I know I am being a bit blunt here, and please don’t take offense. I just don’t want to see you in a situation where you need a machete to get out your front door.