Landscape and Irrigation is read by decision makers throughout the landscape and irrigation markets — including contractors, landscape architects, professional grounds managers, and irrigation and water mgmt companies and reaches the entire spetrum.
Issue link: https://read.dmtmag.com/i/158652
Green Roofs By Marguerite Wells Selecting Plants for Green Walls Fern. Photo by Connor Walsh he plant palette for green walls is much wider than for most green roofs.The term "green walls" encompasses all forms of vegetated wall surfaces — green façades, living walls and retaining living walls. Living walls can be indoors or out, and made of soil, fabric or synthetics. They are nearly always irrigated, so drought tolerance is not particularly a constraint. In choosing plants for a green wall project, these parameters need to be outlined to give shape to the plant list. For indoor walls, tropical plants need to be used. Even with auxiliary lighting, the light levels indoors almost always necessitate plants that do not expect winter, which generally means tropical species. T 12 Landscape and Irrigation September 2013 Outdoor walls can grow a wide range of plants, and the direction a wall faces is critical in determining the plant list. For example, a north-facing wall will sometimes never receive a single ray of direct sun. A south-facing wall may never have a moment of shade. East and west have different temperatures. Surrounding buildings affect these parameters as well. Also, winter care is a challenging part of wall maintenance. In the north, fabric-based, hydroponic walls are difficult to maintain perennial plants because the roots are exposed to the coldest outdoor temperatures, without the usual buffering effect that soil provides plants in winter. Even in soil-based walls, drying in winter is a problem — so look for plants that can withstand substantial drying in winter. Winter aesthetic interest is also a factor — a wall looking green and beautiful in summer is not too hard to achieve, but keeping things looking even halfway decent in winter, and managing customer expectations regarding this, is a challenge in colder climates for exterior green walls. So, with all those parameters in play, how can I recommend any particular species for living walls? One category is known as Mondo Grass. Evergreen, tough and grass-like, I see this used commonly in exterior green walls. Some cultivars are very popular, and, as a result, can be hard to get and/or expensive. Others are very common and relatively cheap. They are propagated mostly by divisions, and are big plants that are not commonly found in small plug sizes because they just won't fit. There are several genera of plants that use the common name Mondo Grass, including Dwarf and Black Mondo Grass, which are in the genus Ophiopogon, and the many cultivars of the genus Liriope, which come in mostly green foliage, including variegated green leaves, and many shades of blue and purple flowers. Some like more sun than others; some of the bigger varieties can be aggressive groundcovers; and some smaller selections are slower growers. Another common denizen of green walls are ferns. There are different species to use indoors or out (for interior and exterior living walls), sun versus shade and evergreen versus deciduous. Some ferns stay small, others get quite big. A common North American native fern that is everwww.landscapeirrigation.com