Do you often dream of mountains and rock gardens, while your own garden looks like a plain sheet of paper? If so, then maybe you should consider erecting a dry stone wall by yourself. All you will need for such an undertaking are some stones of various sizes, either natural or dressed, gravel and planting soil for the rock garden plants.
A dry stone wall is built without mortar holding the stones together. It is not only beautiful, but also durable and impervious to rain ar cold. The wall slightly settles and shifts in time, and the individual stones do not crack or deteriorate in response to frost heave. Stone walls also offer a charm that no other material can equal, and are especially beautiful when planted with summer flowering alpine plants.
A standard freestanding wall is usually 60-120 cm high, slightly tapering towards the top with a slope of at least 5 degrees to a face. A wall may be any height, providing the base width is around half the total wall height (so if you are building a wall 1 m high, the base of the wall should be at least 1.2-1.5 m wide). The wall is made up of two parallel faces of coursed stones with its centre carefully filled with a mix of crushed stone and soil.
The following steps will help you create a stone wall that will beautify your property for a long time. For the wall base, dig a shallow foundation trench to the depth of 30 to 50 cm. The depth of the trench depends on how well drained the site is: the more waterlogged it tends to get, the deeper trench will you need. Fill it with building rubble, crushed stone, gravel and sand. However, if the trench is shallow enough, sand will suffice. Rake and tamp it down. The base of the wall should be below the original soil level by 3 to 6 cm, so do not fill the trench to the very top. This will greatly increase strength of the wall, and will also give it an appearance of being bedded into the ground. Bind the stones with some planting soil mix, which should be loose, fertile and free draining, ideally made of 2 parts of compost to 1 part of sand.
For the base of the wall lay the stones to span the whole width of the wall. After a few courses have been built in this manner, continue building the wall as two parallel faces. Fill the gap in the middle of the wall as you go with a mixture of crushed stone and soil, and compact it firmly.
The courses are stacked with 1-3 cm gaps between the individual stones, using planting soil layer as a jointing material between the courses. The soil mixture also fills all the voids, allowing for a better fit between the stones, without having to cut them to size. However, use the soil mixture sparingly, otherwise rain water will flush it out. The stacking process is not unsimilar to that of bricklaying, where a layer of mortar is troweled on a row of bricks before another course of bricks could be bedded.
A stone course is laid on top of the previous one, each stone being placed so that it overlies the joint between two stones on the lower layer. More courses are then laid on top, setting each higher course of stones back by a couple of cm, creating a continuous back-leaning face, so that the wall is narrower at the top than at the base.
As you stack each course, place several large “through-stones” with their length running across the the width of the wall to tie the two wall faces together. Keep moistening the infill of soil and gravel within the wall to help the mixture settle.
Finally, the top of the wall could be finished off by a row of large flat stones. Alternatively, you could fill it with planting soil. Water well to compact the soil and eliminate any gaps. After the wall had a thorough soak, plant the rockery plants.
For a slightly different purpose, you could build a dry stone wall for a shady and damp garden spot. However, choose a more appropriate stone for such an undertaking such as granite or basalt. Before long the shady dry stone wall will be covered in mosses and lichens, giving the wall an aged look. The voids and crevices in a dry stone wall, when filled with a mixture of peat and fertile loam, provide a perfect habitat for a wide range of shade-loving plants – ferns, hostas, saxifrages, alpine lady`s mantles, anemones and primroses.
© Giedra Bartas, 2011