As with any gardening job, the end result will only be as good as the preparation you put into it and for building a rockery in your garden this means avoiding a site that is prone to being boggy, or worse yet, flooding.
Secondly, make sure you dig over the site thoroughly and break up the earth. Then add plenty of rough rubble finishing off with a layer of smaller and rounder rubble.
Choosing the Rock
If you think building a rockery is just about putting any old rocks into your garden , then think again. The main determining factor here is, is there is a particular rock type in your locality. If there is then this will be the best one to use as, just by looking at the plants in your locality, you can easily tell what plants will grow best in a rock garden of local stone. Also it will involve lower transportation costs and a smaller carbon footprint to get them in place.
However, should you live somewhere without a naturally occurring local stone, say in a river delta, then you may have to cast your net a bit wider. Something to consider here is that a ton of sandstone has twice the volume of some limestone rocks, so according to the density of a particular rock you might get more, or less, bang for your bucks. Having said that though, sandstone won’t weather as well as limestone, so if you’re in a particularly cold and wet region a more durable stone might be worth the extra outlay.
A low cost alternative to buying rocks is to make your own. Tufa stone is ideal for a rock garden being light weight, easily handled and porous. All you need to do is mix one part cement, two parts sand and two parts gardening peat until you get a plastic consistency.
When left, this will harden into stone, to get the size and shape rocks you want pour it into cardboard boxes of different shapes and sizes to set. When set the cardboard can be torn away and any rough ridges chiseled down.
Arranging the Rocks
Having prepared the base you can then create the pile of earth that the rocks will be placed in. Have a look at how rocks are arranged in nature and try and emulate those arrangements.
The key here is that you want it to look natural, not like you’ve deliberately placed them on top of the earth looking like decorations on top of a cake. This means mixing small and large rocks, allowing varying amounts of the rock to be exposed and hidden but always making sure that the best ‘face’ of the individual rocks is the one on show.
Placing one rock directly on top of another is OK if you know you’ll be adding pants that can thrive in that environment. A better solution is to lay one rock, place some smaller rocks or stones on top of it, then balance another rock on top.
You can then in-fill the gap with earth forming an earth layer for plants to be bedded into. Finally, do leave the design for a couple of weeks for the earth to settle before starting to add your plants
If you get heavy rain the last thing you want for your rock garden is for it to look like a waterfall. This is where that preparation comes in. Having put a layer of rubble at the base of the rock garden it will have good drainage.
To make sure the water drains into the rockery, away from the face of the rocks, slightly angle them downwards into the earth pile. Along these ravines and gullies lie the ideal positions for your water loving rockery plants.