IN NATURE, PLANTS CAN BE FOUND GROWING ON VERTICAL SURFACES LIKE CLIFF FACES OR TREE TRUNKS. UNDERSTANDING THIS GROWING ENVIRONMENT IS KEY TO SUCCESSFULLY REPLICATE IT IN VERTICAL GARDENS.
Most natural vertical surfaces on which plants are found are soilless, creating well-drained growing locations. Many plants thrive in such conditions — on rocks and cliff faces, or branches and trunks of trees. These plants are called lithophytes, from the Greek lithos (‘stone') and phyton ('plant'), and epiphytes (epi is Greek for 'on'). VGD's felt-based technique imitates these conditions and allows a large variety of plants to naturally grow on vertical surfaces.
Epiphytic plants are most common in humid and rainy tropical climates. Typical epiphytic houseplants are Asplenium nidus (bird's-nest fern), Platycerum bifurcatum (Staghorn fern), Aeschynanthus radicans (Lipstick plant), and aroids such as Philodendron, Anthurium, and Monstera.
As with epiphytes, lithophytic plants are more frequently found in places with high humidity, such as on coastal cliffs or next to waterfalls. Saxifragaceae is a family of plants often found growing on rocks, like the Himalayan Bergenia or North American Heuchera.
CHOOSING THE RIGHT PLANTS
Apart from aesthetic preferences and the plants’ ability to grow in a soilless, vertical location, the selection of plants is mainly decided by sun exposure and the local climate. In urban areas, these factors can be influenced by tall buildings that funnel winds and irregular patterns of sun exposure. Studying local flora gives a good idea of what plants to use. While wild species are rarely available in nurseries, the local flora indicates what related species can work.
With different climates and a larger variety of plants available, outdoor vertical gardens allow for more varied designs. For example a sun-exposed wall in a Mediterranean climate can be planted with aromatic Mediterranean plants like Lavandula, Thymus, Rosmarinus or Salvia. On the other hand, an almost tropical touch can be added to a shaded wall in the same location with plants like Begonia, Arum, Davallia, Asplenium, and Fuchsia. A vertical garden can be built in virtually any location, except for extremely cold climates. As with any garden it’s key choosing the right species for the right location.
Indoor climates typically include a temperature of around 20° C and low light levels. Similar conditions can be found under the tropical forest canopy where little light filters through. Many plants have adapted to such environments by growing large leaves in order to absorb as much of the small amount of light that reaches them as possible. They tend to have quite modest flowering, although there are exceptions that flower freely all year long in low light levels. Common plants used indoors are aroids like Philodendron, Anthurium, and Epipremnum or gesneriads such as Aeschynanthus, Columnea, and Saintpaulia, many species of Peperomia and Begonia or different ferns like Nephrolepis and Pteris.
MORE ABOUT PLANTS
Natural vertical landscapes are an important reference when creating a vertical garden, and also have great inspirational value. Have a look in the blog for more pictures of plants and landscapes from our field trips.