Types of garden walls

Free standing

The simplest walls are free standing and these are normally used when boundaries are walled. In the UK garden walls above 2 metres high, unless they face the public highway when its 1 metre, require planning permission. That said this is only a basic guideline and local rules or covenants can often apply so before you start any work you should make a quick call to you local planning officer. In practice these heights are quiet sufficient and you would need a very good reason before the authorities will allow you to exceed them. When considering the height of the wall you have to remember that if the ground level is lower at one side of the wall than the other the measurement is taken from the lower side and the height includes all parts of the wall including pillars, copings or anything else attached to the wall.

These days most garden walls are either ½ or 1 brick thick; though older gardens will often have 1½ or 2 brick thick ones. The choice of wall thickness will in the first case be determined by what is needed to ensure the wall is stable but then a thicker construction may be chosen for aesthetics. Clearly the thicker the wall the more expensive it will be and all walls are expensive, so a good reason is needed to make a wall thicker then it has to be. An excellent guide to the wall thickness needed for a particular location in the UK can be seen on the Government’s Planning Portal.

 Heated walls

 The idea of using a garden wall to provide heating may seem strange and very wasteful to us now, but at one time this was state of the art gardening. The walls were built with fireplaces spaced along their length and the chimneys took the form of brick flues snaking up through the walls. The hot smoke and gases from the fires passed up the wall flues, heating the wall as they went. Many are still seen in old large estates around vegetable gardens where they heated lean-to greenhouses built against them. They are easily spotted by the chimney post along the top and are usually thick and generally two stories high.

Heated Garden Wall from The Book Of Garden Management by S. O. Beeton
Heated Garden Wall from The Book Of Garden Management by S. O. Beeton

 Retaining walls

This is the commonest reason for walls to be used in a garden. Where a garden requires a change in levels, either by design or necessity, a wall is the most efficient method of achieving this. The wall must be sufficiently strong to support the material it is holding back and in the majority of circumstances this is achieved by the weight of the wall.

In most cases in the garden the amount of material being supported by the wall will be relatively small and the potential danger from the wall failing will be small. In practice, the aesthetics of the wall design will mean it will be sufficiently strong, but if the wall is going to need to be higher expert advice should be sought. Because by their nature retaining walls cut across the natural drainage of the ground there is a danger of water building up behind retaining walls. This can weaken the soil around the wall foundation and therefore weaken the wall. To prevent this drainage must be provided behind retaining walls which empties out through small holes in the wall called weep holes.


 The 18th century saw the English “leap the garden fence” and develop the English landscape Garden style where countryside became the garden, all be it in a much stylised form. To achieve this, the garden boundary had to be hidden to allow the garden to visually run seamlessly into the surrounding fields. To achieve this; the wall is set into the ground below eye level. In practice this is a very expensive process, generally requiring large amounts of earth to be moved in addition to the cost of the wall.

Sketch of a Ha-ha

Botany for Gardeners by Brian Capon

The danger with this book is that is title may well put off many potential readers. The vast majority of gardeners do not see themselves as botanist: but spending hours studying the plants they grow, can’t grow and aspire to grow. As a gardener you consider the plants shape, colour, needs development and reproduction; yet little thought is given to the science under pinning these characteristics. All too often the science bit it shied away from as being too difficult or not relevant; more likely than not because we were put of the subject at school. The thing is gardening is to a large part applied botany and to deny it is not only short sighted but also making life harder. The problem is at first botany can be off putting in its apparent complexity and little is available in the way of bridging this gap. Brian Capon has set out to do just that with this book.

A professional botanist by training and a gardener by inclination, he has set out to provide a means of introducing gardeners to the how and why of plants. In doing so he has created a book that fills a real gap in gardening literature.

His years teaching botany, often to non-botanists, has given him a natural ability to do mystify his subject. Like all good teachers he has a natural gift for bring his subject to life and sharing his enthusiasm. The different aspects of the subject are approached in a logical order and the book is kept sufficiently concise so that it dose not intimidate those new to the field. It is well illustrated with photographs, line drawings and examples to add understanding. Though no part of the book can go into great depth, doing so would be counter productive, it ends with a list of further reading to encourage the reader to delve further into the subject.

Hopefully the present upsurge in interest in science will encourage gardeners to set aside there feat of it and temp them into learning a little bit more about the plants they grow. The book will not necessarily make them botanist; but it will make them better gardeners.

Garden walls

A sketch of a garden gate leading into a further part of the garden.The wall is one of the oldest manmade structures, and its use in gardens is as old as gardens themselves. The word comes from the West Saxon weall which in itself comes from the Latin vallum meaning a rampart and in the garden walls are used as a natural development of earth ramparts. Initially walls in gardens were to divide the gardens private space from the rest of reality, but over the centuries their roll has evolved.

It must have quickly become apparent that walls change the immediate environment around them; providing shade, shelter, warm and support. A wall facing the south will create an area of warmth immediately in front of it both by reflecting the suns warmth and by absorbing this heat and then gradually releasing it after the sun has gone down.  An east facing wall will heat up early in the day and then release its heat when it is in shade in the afternoon, where as a west facing one will heat up later in the day preventing the rapid and damaging thawing of delicate spring blossoms. A north facing wall on the other hand will be cool and shady demanding plants suited to those conditions.

What is often over looked though is the effect walls have on the moisture in soil immediately beside them. The porous nature of brickwork will tend to draw moisture from the soil against it.  A greater effect though will be from the tendency to prevent rain being blown onto the leeward side of the wall; making the side sheltered from the prevailing wind drier. This effect will be further exasperated by any over hanging coping and more so by the eves of a roof.

In addition walls have a psychological effect; changing the way we perceive the space they enclose and its relationship with what is beyond them. Their presence can create a sense of privacy and security to those on both sides of the wall. Even a low wall creates a strong dividing line between the parts it separates; allowing the areas within the garden to be compartmentalised according to their form and/or function. Thereby creating uniformity: stopping different styles and uses clashing; in forcing a sense of order.

A further layer is added to this relationship by the openings placed in walls. Large ornate gates form an imposing status symbol, framing and thereby controlling the view of the area with in. Small openings control both the access to the interior space and what can be seen of it creating a different sense of drama. This can be further manipulated by the choice of how this opening is filled. A solid door will block the view out of the walled area while creating a sense of mystery: while one that you can see through will entice the viewer though into the space beyond.

Each wave of garden design style has found new uses for walls, as the demands we place on gardens change and new materials to construct them from become available. Thus the role of the garden wall continues to develop with each generation of gardeners.


This is the process of classifying things into groups, and in biology placing them within a hieratical system of classification. It is the study of how living things fit into system of how we name them.


This is a group of closely related genera and the names should be written in italics (or underlined) and start with a capital letter. The names of plant families should end in the letters –aceae; but some long established names which do not have this ending are still used, all be it with standardised alternatives used in parallel.

Utility areas

Most gardens end up with an area for the bits you would rather not show off; where pots, wheel barrows and the like need to be stored. These areas need to be kept clean and tidy, so the paving needs to be smooth and easy to clean. As this is the working part of the garden, cost is an issue and often the cheapest smooth flags will the best. Where the area is going to be heavily used; or a greenhouse or heavy shed are to be set on them the solid 50mm thick flags are a better bet. Alternatively a plain concrete pad can be laid. In any case, as with all paving, care should be taken to ensure the paving is laid onto a good base capable of supporting the weight of what ever is going to be placed on the flags. Consideration should also be given as to the drainage of the area with a good fall towards an area of the garden any water can safely soak away into.

Sometimes the line between the garden and the utility area can be blurred, particularly where fruit and vegetables are to be grown. Gravel paths look very good running between vegetable beds but the work in them invariably involves stepping between the path and the soil. This will always result in soil ending up on the path and you want to be able to easily clean this off if the path is to remain usable. Clearly this is going to be very difficult with a patterned flags and impossible with a gravel path. Here pragmatism should not be sacrificed for appearance. Grass paths do provide an alternative to paving stage-manage but you have to consider if their appearance outweighs the problems of cutting them and their becoming muddy. While grass paths through provide a softer organic appearance to say a vegetable garden they are not easy to clean, can be difficult and time consuming to mow and can quickly become muddy if used a lot in wet weather.

International Code of Nomenclature for Cultivated Plants

The International Code of Nomenclature for Cultivated Plants (ICNCP) lays down a set of rules in an attempt to standardise the way plants produced or selected by humans, as opposed to wild plants, are named. It is in effect a supplement to the International Code of Nomenclature for algae, fungi, and plants (ICN).  The first edition of the code was published in 1953 with the hope of applying some order to the naming of cultivated plants and in 1988 Hortax, a committee if plant taxonomists, was set up to supervise its continued development. The most recent edition, the 8th, was published in 2009.

The Cambridge Illustrated Glossary of Botanical Terms by Michael Hickey and Clive King

This may not seem an obvious choice to include in this list and retailing at about £38 for a paperback it is not exactly cheap; but it does plug a very important gap. This book provides an accessible explanation of the often confusing technical terms used to describe plants. These are words used in botanical and horticultural books and other literature to describe plants and their characteristics. Their use causes considerable confusion and, sadly, puts off many; but are vital to help describe plants in an unambiguous way. The result is that many plant descriptions rely on words which make no sense to most people or very specific uses of words with much broader colloquial means. Frustrating as this is the accurate naming and description of plants would be impossible without them; as they allow the necessary degree of precision when trying to describe the difference between plants.

To achieve this, the book is divided into two sections; the first provides a list of words with a brief explanation of the meaning and cross references to the appropriate illustration in the second section. This second section justifies the large size of the book: being A4 in size. This is a selection of clear black and white line drawings illustrating the many terms. Most books attempting to describe this with illustrations rely on photographs, but such a technique could never achieve the clarity that these accomplish.

While of limited use to many people, and hence the publishers high price, anyone serious about understanding plants and there descriptions would do well to get hold of a copy. This is not the sort of book you are going to sit and read it is one you are going to find you are repeatedly pulling down of your shelves to refer to.