What's in a name you might ask? When naming plants using scientific nomenclature, a lot of Latin is thrown around. But why would I want to know the differences between a genus, species, subspecies, variety, cultivar or even a hybrid? Maybe so that you could pick a plant that is adapted to your area and has the traits you desire.
A genus is a group of plants or animals that have fundamental traits in common but differ in other characteristics. A genus example for a tree would be maples or Acer. The next taxonomic level is species. A genus can contain many species. A species is a natural group in the same genus made up of similar individuals that can produce offspring through sexual reproduction. An example would be the red maple, Acer rubrum.
Subspecies are a further division within a species containing similar reproducing individuals but usually separated geographically from other subspecies. If two subspecies of the same species are brought together, they can readily reproduce with one another. Geographical isolation has allowed these separated groups of individuals to develop some traits that are different from each other.
But what about varieties? These can be naturally occurring but are frequently created by man. The seed from varieties will always breed true. These will have distinct but less conspicuous traits in common. Maybe a white flowering redbud rather than having the typical red flowers. Another tree example would be Acer rubrum var. drummondi.
And then there is the cultivar. Actually, most nursery bought plant "varieties" are really cultivars. A cultivar is always created by man and is usually propagated vegetatively (asexually) such as through root cuttings or tissue cultures. Seeds do not breed true. Cloning is an example of vegetative propagation. Hybridization is another example and is the crossing of genetically dissimilar individuals. It can occur both in nature and at the hand of man. Hybrid seed that you save will often produce new plants but they won't necessarily breed true and retain their original hybrid traits. An example of a cultivar would be Acer rubrum "Autumn Flame."
Now that we have the terminology mastered, what can cultivars do for you? Cultivars have been developed that resist disease, tolerate heat, provide shade without messy fruit or seeds, transplant easier, have a crown form that fits your space better, tolerates salt, tolerates alkaline soils, displays unusual leaf colors or flowers, grows rapidly, resists insects or tolerates drought. Unfortunately, not all the traits you may want can be found in a commercially available cultivar.
These desirable traits can lead to a reduction in need for pesticides, reduce maintenance, improve plant health, provide a size or crown shape for trees that allows their use in specific sites, and eliminate nuisance fruit dropping. By improving the overall health and adaptability of a plant, one can hopefully find a cultivar that will be more suited to the conditions of the desired planting site. The next time you are shopping at a nursery, maybe you will have a better understanding of the nomenclature found on the plant's tag.
Jim Leser retired to Cedaredge in 2007 after a career with Texas A&M University Extension in entomology. He is a member of the Cedaredge Tree Board and a Colorado Master Gardener.