High-tech greening systems are an alternative to classic facade greening. They are increasingly used in modern architecture, especially for expensive, high quality, and representative facades in southern Europe and Asia (e.g. Singapore). A pioneer in this style is the Frenchman Patrick Blanc with his "vertical gardens." The greenery there does not grow upwards from the ground or from pots, but sits on the facade in the form of planted modules. Such facade gardens are usually very expensive and maintenance-intensive; the plants must be replaced (in our latitudes) almost every winter. Alternatively, there are planting bags/pockets and similar suspension systems on the market, which make this replacement of plants easier.
For such greening concepts, two guiding principles are combined. The first is the fact that some plants have the ability of growing on stone with very little topsoil. This phenomenon is then applied to facades and fronts of houses. The second guiding impulse was to suspend plant pots/baskets, as often seen in the streets of southern Europe, and hang them tightly next to and on top of each other to create a specific but also and broad-areal effects. Thus, modular green systems were created.
The plants grow in special pots, plant pockets, or substrate boards/panels freely into space. Irrigation equipment, together with pumping and measuring instruments, are usually attached there. Also an automatic supply of fertilisers is often integrated. Climbing supports are usually not necessary with such projects. In 2013/2014, a pilot project was carried out on a noise barrier at the Palmengarten in Frankfurt Germany, where four different greening systems of 12 sq.m each were tested. The results could now be trend-setting for further wall gardens in Germany.
Low-cost solutions include 'metre-long hedges' (a 'hedge wall'), which is also suitable for greening facades or for suspension systems with pots and plant pockets, which are watered manually and removed in winter. A further variant is the use of self climbers in wall areas demarcated by recesses or protrusions-- so, naturally occurring 'niches' -- defined surface-area growth and a lower-maintenance wall garden.