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Martin Quigley, The Ohio State University, Horticulture and Crop Science; James A. Chatfield, Kenneth D. Cochran, |
There are, of course, other official names of plants in addition to the Latin binomial for the species, such as botanical varieties and subspecies, hybrid designations, patents, trademarks, and something very important to horticulturists the cultivar.
Earlier in this century, the great plantsman Liberty Hyde Bailey coined the term cultivar for cultivated variety. For woody plants, cultivars are trees and shrubs that are cloned, e.g., asexually propagated (cuttings, grafts).
Here is an example of how cultivars are named. Some seedlings of the Norway maple, Acer platanoides, were seen to have reddish new growth and a wider spread – and were then cloned and sold as the cultivar Acer platanoides 'Schwedleri' and marketed as a Norway maple with these characteristics. Some seeds from this cultivar were also then planted out and one was noted to have season-long maroon-red leaves. This seemed to have great potential for the industry, so it was selected, cloned, and sold as the cultivar 'Crimson King.' The rest is history.
Note: Cultivar names are written with single quotes, and the first letters are capitalized: Acer platanoides 'Crimson King' or Acer platanoides cv. Crimson King.
Knowledge of different cultivars is critical to good communications and good horticulture. Here are a few examples.
Example No. 1
Not knowing about cultivars and how they differ can lead to over-generalizations about plants. In recent years, Bradford pears have received bad press because of their tendency to break in storms due to narrow crotch angles. Many street tree commissions, for example, have reacted by banning the use of all pears. This may be an example of throwing out the baby with the bath water, because most people do not know the nomenclature of the flowering pears.
Bradford pear is actually only one cultivar of the Callery pears in the genus Pyrus. It is:
Many other Callery pears have less tight crotch angles and hold up better in storms than this cultivar. For example:
Thinking that all the ornamental pears are Bradfords is a common mistake. Knowing the difference between cultivars is part of what makes you a knowledgeable horticulturist.
Example No. 2
How many of you have heard landscapers complain that they planted dwarf European cranberrybush viburnums that in a few years turned out to be four to five feet taller than desired? They complain about the nursery or garden center, not realizing that the problem stems from the plant they asked for or deliberately purchased. This is often due to a lack of awareness of the names of the plants involved. The species for European cranberrybush viburnum, which will grow to 12 feet or higher, is:
The commonly planted cultivar that many people think is a dwarf is:
However, though it is smaller than the species, growing to maybe six feet, and is denser in its growing habit, it is not really a dwarf. For that you might plant:
which will grow to about two feet. Knowing what you need to request, buy, and plant is a big professional plus.