Vegetation

For rapid coverage of a green facade, plant specimens should be healthy and vigorous, with numerous basal shoots. They should be of the largest possible size to suit the installation.

ns_Desal December 2013a

Green roof at the Desalination Plant, Wonthaggi, Victoria

To support the vegetation at installation, the growing substrate used to support container-grown facade plantings should incorporate controlled-release fertiliser at planting (see more information about plant nutrition here). New plantings should receive irrigation to promote their strong establishment, which depends on season planted and plant size. Establishment is when new roots have grown and the plant is acclimatised and actively growing.

Pruning and training of new plants is essential to promote the development of an effective facade. Plants may need to be trained to the facade support, or temporarily attached to the wall after planting, to encourage upward growth. Once the plant is established, the main runners should be trimmed to encourage lateral shoots that will create a more radial growth pattern. If this is not done, the climbers will typically branch out only once they have reached a significant height, and it may take years for the lower portions of the facade to receive any coverage. The use of diagonally oriented cables on facade systems facilitates horizontal, as well as vertical, growth of the plant (preferred over the plant shooting straight up) and thereby increases the density of foliage cover. For long-term installations, pruning to rejuvenate might be required. As climbers age their growth can decrease and cutting back to hard wood can revitalise a plant and allow for longer lifespans. This means that after five to seven years, especially with woody climbers, it may be necessary to prune back a large portion of foliage.