A botanical name is a formal scientific name to each individual plant conforming to the International Code of Nomenclature for algae, fungi, and plants (ICN). The purpose of a formal name is to have a single name that is accepted and used worldwide for a particular plant or plant group.
Botanical Names of Green Roof Plants
For example, the botanical name Sedum reflexum denotes a plant species which is native to Northern, Central, and Southwestern Europe, where it has accumulated various names in many languages. Later it has been introduced worldwide, bringing it into contact with even more languages. English names for this plant species include: Reflexed Stonecrop, Blue Stonecrop, Jenny’s Stonecrop and Prick-madam. The cultivar Sedum reflexum ‘Blue Spruce’ is a blue-green-variegated horticultural selection of this species.
Botanical names prevent people from confusing different species of plants, but also indicate that different species are related. The genus (ex. Sedum) is the unique name followed by the species (ex. reflexum). The first letter of the genus is capitalized and the species in small letters. Most of these names have their origin in Latin or Greek, are combinations of languages or words, the name of somebody who is honored, appearance or location.
Knowing what the Latin (and sometimes Greek) words mean can help gardeners with their planning and maintenance chores. For instance, if the available area is cramped, a plant with arboreum (tree-like) or altissimum (very tall) in its name might not be the best choice.
Some names refer to special characteristics of the plants. Pubi, hirti, villi, and barbi are all “combining forms” suggesting hairiness. Combining forms are Latin roots with vowels added to facilitate pronunciation. They frequently appear attached to more familiar Latin-based words, like those for leaf and flower. Hirtifolia would mean hairy leaved. Barbiflora would mean bearded flower.
It is getting really interesting when we look at cultivars of plants like Sedum reflexum ‘Blue Spruce’. ‘Blue Spruce’ is a blue-green-variegated selection of this species. Variegation of plants can be caused by environmental conditions (air quality, sun light, nutrients, water supply etc.) or by targeted human influence like propagating only the plant with certain properties, propagating plants with “defects” or Gen manipulation (like most of our food plants, ornamental plants or turf grasses).
Vegetation for Green Roofs should be identified, specified and communicated by their botanical name to avoid confusion. The names of the plants must be written correctly according the International Code of Nomenclature and professionals don’t refer to the “Latin” name of a plant – they refer to the botanical, horticultural or formal scientific name of plants.
Recommended readings (only English):
•• Mabberley’s Plant-book: A Portable Dictionary of Plants, their Classifications, and Uses [Hardcover] An Aid to the International Code of Botanical Nomenclature
By Jörg Breuning