Cultivars (short for "cultivated varieties") are plants you buy that often have been propagated not from seed, but rather vegetatively (for example, via stem cuttings). With this method of propagation, you can be sure that the offspring will retain the characteristics of the parents for only that one generation. That is, plants grown from the seeds of cultivars may disappoint you, failing to stay true to form.
In terms of how they come about in the first place, cultivars can begin as:
- Hybrid plants
- Sports (plant mutations)
The term, "cultivar" is commonly used in discussing plant taxonomy. When the full scientific name for a particular plant cultivar is given, the part of the name that indicates the cultivar, itself follows the genus name and the species name. Furthermore, its first letter is capitalized, and the name is set off by single quotation marks. By referring to such plants in this way, we are able to be more specific about them than if we restricted ourselves to noting genus and species.
Cultivars Versus Varieties
In contrast with a cultivar, a "variety" (sometimes abbreviated as var.) can often be found growing and reproducing naturally in the plant kingdom. Plants grown from its seeds will often come out true to type. If you remember that "cultivar" stands for "cultivated variety," you will have no problem remembering the difference between the two.
Whereas a plain old "variety" is a natural phenomenon, a cultivated variety is a fluke that has been propagated via human intervention. Its continued existence (in the desired form) from one generation to another requires human intercession -- just as a cultivated piece of land can retain its appearance and composition only through continual human efforts.
In fact, "cultivated" derives from the Latin root meaning "to work the soil" or "to tend to something with religious devotion." That Latin root also gives us such words as "culture" and even "cult."
When a variety is named in writing (for example, in a book, on the Web, or on a plant label), it should appear differently than a cultivar name does (although we are sometimes careless in this regard). Rather than being presented in single quotes (with the first letter capitalized), it should be italicized and in lower case -- just like the species name, which it follows.
Legal Issues, and Why Cultivars Are Developed
Above, I mentioned the difficulty in propagating plants that are cultivars. The process is not as easy as saving seeds at the end of the growing season and then sowing those seeds next year. But this is much more than a matter of "difficulty." Think of a cultivar as a patent on a plant, a patent that yields royalties when the plant is sold. The patent belongs to the plant developer. According to the Oregon State University extension, "If a plant is patented, a license is required from the patent holder in order to make cuttings of that plant, even if it is planted in your own back yard." So even if you are clever enough to figure out how to propagate a plant vegetatively, be aware that, technically, you could get into trouble for doing so.
If you decide you like that plant you bought a few years ago at the garden center, you need to go back and buy another.
This restriction gives plant developers the financial incentive to invest on research into the breeding of new plants. Which raises the question of the purpose -- from the consumer's perspective -- of having cultivars, in the first place. What do new cultivars have to offer that the original versions of the same plants lack? The fact is, a cultivar may have a particular trait that is superior to (or, at least, different from) the original.
Two examples will suffice to make the point:
- Lovers of the old-time burning bush shrubs craved a newer version that would stay more compact. Tapping into this craving, plant developers bred a more compact cultivar of burning bush named 'Rudy Haag.'
- Likewise, the rap on butterfly bush had long centered on how invasive it is. Indeed, like burning bush, the original butterfly bush is considered one of North America's worst invasive plants. Enter 'Blue Chip' butterfly bush, a non-invasive cultivar.