There are 4 important main aspects that have to be kept in mind when a new bonsai site is planned and constructed.
Location: When I started the construction of the bonsai site in my garden the decision where to build it was made easily, as it was the only logical place where a bonsaisite fitted in the overall design of the garden. But the decision is not always that easy as a lot of criteria must be checked. Depending on the situation of the garden you should plan to situate the stand in a way to provide your trees with enough light but at the same time you should avoid too much direct insolation. This obviously depends on the species of the trees you will need to place at the site, their resistance against hot sun and winds, the way they tolerate shade.
In the case of my garden, the location is quite perfect as it is protected of the hot and dry winds in summer by a hedge of arizonicas at the north and east side, but at the same time a good insolation is assured as the sun in its way from west to east provides sun and light. At the west part of the site I placed the trees which need sun as the serissa and the box tree, and from there to the east side those who need light but don’t resist direct sun.
If the selection of the place is not influenced by criteria such as design or the need to hide it from the main view, some main criteria should be always kept in mind: the place should be protected of heavy or hot winds which could dry out the soil of the trees or even cause severe damage to them breaking branches or pushing them off their stands; it must have enough light without direct sun during the hottest hours of the day.
Shadow: Depending on where the bonsai site is sited, more or less shadowing measures have to be planned and constructed. In some places it is enough to place higher plantings around the place the bonsais are located, in others it is necessary to build effective sunroofs to protect the bonsais against the mean insolation and in consequence, against water loss.
In Madrid the sun conditions are very intense, specially in summer, but sun can be dangerous from march to october. In my case, it was necessary to construct a pergola, 3 m high, with about 20 square meters of roof to create enough shadow for the plants. The roof is covered by a semitranslucid black cloth specially designed for bonsai sites. This cloth is available in most garden centers.
Watering: If the house looks south like mine, sun will be present nearly all around the day, which is good for growth, but at the same time watering has to be prefect. Bonsai trees often have not only small but also very low pots what means very little soil which cannot hold water for a long time. Another problem is that the material of the pots (ceramic or clay) can get really hot which will warm up the soil in them, causing dryness even sooner. To avoid this, a very effective watering system must be installed. It is very good to have gravel on the site floor as it holds the water for a long time and increases the air humidity.
I prefer a micronized rain system connected to the main rinse system of the garden, so one of the programmable stations is the bonsai site. I installed 10 inch tubes at the inner side of the sunroof forming a double “S”. About every one meter a perforation was practiced to insert a micronizer. Depending on the water pressure you can install more or less of these micronizers, in any case you should be sure to cover the whole area. Once the system is installed, you should test it for some days for full coverage of the bonsai area.
It is also very important to moisten the gravel below the stands as it keeps the moisture for some hours and increases the air humidity.
Design: The design of the site, like with any design, depends on the taste of the owner, but it should be sober and effective, combining the main materials wood, light colored gravel and stone. I chose old teak wood for the stakes and lightly red stonetables. The gravel is clear and light brown.