Generally, climbing plants are usually not used on roof greening, but here we'll show you how it can be done. "Garlands" (created from single, freely-tensioned ropes, and other plants can be used to create transparent "green roofs," even filigree, green canopies! Of course this is a question of the sub-construction... while individual tension cables are sufficient for garlands, many cables (and when possible together with a stable clamping frame) are best used for green roofs (in this case, the structure is more of a pergola), since the weight of climbing plants increases with age. From the following examples, learn what to be mindful of when greening 'roofs' and which plants are most fitting. Refer also to our section on pergolas.
Grapevines are particularly suitable for green garlands, roofings, pergolas, balconies/galleries etc.. This type of roof greening needs to be pruned regularly and should always remain airy/well ventilated (due to the risk of mildew). For denser, opaque green roofs, go with Dutchman's pipe, akebia, or wild (grapeless) grapevines... expect a few years for development. Fast-growing annuals are perfect for garlands; they are lightweight, their foliage manageable, and with their annual dying off, there are hardly any structural problems. With vigorously twining plants like wisteria, bittersweet, silver lace (fleece) vine, and kiwi, it is essential to ensure that wire ropes are not permanently entwined. Details for a parallel trellising of the stems/shoots can be found in our 'wisteria' section.
Already in the Baroque era of garden art, people had been experimenting with hanging vine garlands, or "festoons." Later, after electrification, electric cables in rural areas were often routed through a courtyard and the associated strong tension rope was also used as a holding rope for a vineyard garland. For such practical things, farmers have always been enthusiastic! Whether cable and anchoring are suitable for such additional loads must be clarified on a case-by-case basis. Ropes were often also only tensioned for climbing plants, however. FassadenGrün designed the system 0040 for this type of project (through that link you can also find information about unusual structural features, etc..). By juxtaposing several cables, you can form a roof of greenery between two walls. The suspended vegetation can be combined with climbing fields on a wall (via wire rope spans).
One can find strands of green hanging in the alleys of southern Europe. (In Germany, for example, in Freiburg/Breisgau.) Unlike a courtyard greening, with this type of greening permits may be necessary because public road space is required and then 'claimed.' The liability for possible damage (for example: torn out tension ropes) should be clarified with the authorities; then nothing stands in the way of a road greening. Naturally, the greenings will usually be limited to narrow streets, alleys, and pedestrian zones.
A variation-modification of System 7060, such that there are intersecting rope sections, forms a load-bearing structure for the green roof. Plan the cables as high as possible to compensate for a certain sagging of the ropes from the weight of the plants. With the highest possible placement, the leaves and shoots will be able to grow and unfold (often hanging) without disturbing the passageway. Points of distribution for the ropes are often placed on separate wooden supports as with wire frameworks; the posts are to be supported as in the case of wire frames or anchored in the ground according to cable system 0050; when needed, also doubled with offset ropes (support triangle). If necessary, it can be anchored in a nearby wall with short tensioning ropes or stainless steel threaded rods (see photo).
Installation in the upper part of the wall is only permitted if the upper bricks are held by a peripheral tie (ring) beam or are reacting on a heavy concrete roof slab; otherwise, they must be more deeply anchored. A separate permit may have to be obtained at property boundaries if customary fence heights are exceeded. If many ropes run from one point, rings with screw joints/links must be added. Use cable with a maximum thickness of 3 mm so that they can absorb peak loads rather than the support post.