Apart from the plants, the most important element in the rock garden is the rock itself. If the rock garden is badly built or if the wrong rock is chosen for its construction, it will never look satisfactory, and will be
a constant source of disappointment every time you walk around the garden.
Rock is heavy and expensive to transport, so whenever possible acquire it locally. You should be able to find a local quarry by doing a search on the internet for your county and the word 'quarry', or consult the British Geological Survey's Directory of Mines and Quarries to get started. If you only want a small amount a garden centre should be able to provide it.
Read our guide to making a rockery
Choosing the best rockery stones
It is important to bear in mind, however, that some types of rock are wholly unsuitable for rock garden construction.
Featureless rocks, such as granite and ironstone, and those that weather badly, such as friable oolitic limestones and shales, should be avoided. Instead, select a hard rock with good lines (strata) and other features. Rocks with character, such as hard limestones and sandstones, are ideal, and they have the added advantage of being easy to split if that becomes necessary.
If you want a large amount of rock, it is best to buy it from a local quarry or stone merchant, where you will be able to select those rocks you want for yourself, and where it will certainly be cheaper. If you want just a few pieces, most garden centres supply various types of rocks, which are priced per piece.
Remember that larger rocks are more effective in the rock garden than lots of small pieces, but this depends somewhat on how easy it is to move the rocks on to the site.
When the rock is delivered to your home, try to make sure that it is dropped as close to the rock garden site as possible; this will save a great deal of time and energy. Take care that pieces do not fall on your feet or hands, and be especially careful if children or pets are in the vicinity.
When you handle rocks, wear gloves and stout, protective boots, especially when you are moving large blocks of rock.
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Types of rock
This sedimentary rock is high in calcium and is, therefore, no good for acid-loving alpines. Limestones can be hard or soft and usually have well-defined stratum lines. Soft limestones are useless for rock garden construction. For conservation purposes, avoid weatherworn surface limestone, which will have been stripped from the landscape.
Another sedimentary rock, sandstone can be very variable in texture and colour, although sandy colours, browns and reds are usual. The most suitable sandstone rocks are those that have well-defined stratum lines. Not only will they look more attractive in the rock garden, but they will also be easier to split if necessary.
An ideal rock for many alpines, tufa is very porous and can be easily drilled to create holes to accommodate plants. It is also light in weight and therefore easy to transport. Mineral-rich and often high in calcium, tufa is formed where mineral-rich waters are checked – in gorges or by waterfalls. It is, however, expensive and rarely available in quantity.
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Moving rock and stone
When you have to move heavy rocks, always take every safeguard, and be particularly careful about not damaging your back when lifting. Large rocks can be moved small distances by levering them with iron bars or crowbars. On flat or gently sloping ground, rocks can be placed on a wooden block and moved to the site by employing a system of rollers, which can be made from short lengths of scaffold pole or broom handle.
As the rock moves over the ground, the rear rollers can be moved to the front. Large, heavy rocks can be manoeuvred into position using a block and tackle. Smaller rocks can be moved in a wheelbarrow. Those with a pneumatic tyre (tire) are ideal, and will cause least damage to lawns and pathways.
Move the largest rocks into their final position first, adding the smaller ones after you are satisfied that the ‘bones’ of the rock garden are satisfactory. There will always be plenty of small pieces and fragments of rock left over, and these are ideal for decorating the surface of the rock garden or for using in troughs and other containers.
How to move large landscaping rocks
Use a stout iron bar or crowbar to lever rocks short distances. A piece of wood or small rock placed under the bar will act as a fulcrum against which to lever.
When moving rocks a distance across the garden, use a porter’s or sack truck with pneumatic tyres (tires), which will cause little damage to lawns or pathways. Use a wheelbarrow for small rocks.
For large, heavy rocks, a series of wooden planks or firm mats and rollers can be used. The rock is worked on to a mini-palette or tray and can be easily pushed over the rollers. As the rock progresses, the rear rollers can be moved to the front.
Buy a beautiful Alpine rock garden collection from Saga Garden Centre for just £15.99 with free P&P.