Cultivar trees can be classified as a subspecies of the varieties of plants that exist through “cross-breeding,” or, as some call it, artificial selection. The term itself is a combination of “cultivated” and “variety.” In this sense, variety means the different types that exist within the same species. If one variety was especially good at surviving during the winter and another had a thicker skin, for example, they might make a good cultivar. A new thick-skinned variety that manages winter temperatures well results. A cultivar is a plant or tree chosen by humans because the traits it offers are appealing. It’s with the preferred traits in mind, then, that the species is modified, becoming a cultivar.
“Cultivar” is a term known on an international stage and can be even more specifically represented by plants that are distinguishable from others by their cultivar trait or characteristic. When reproducing cultivar trees, the preferred traits are passed down to the next generation. The new subspecies will have the specifically “chosen” traits programmed to reproduce in future generations. If they’re not able to self-fertilize, they can go through a process of cloning, which is sometimes also called vegetative propagation. However a tree’s genetic lineage continues, its particular characteristics make it a cultivar.
The nomenclature surrounding the term “cultivar” is actually narrower than a specific group or species and perhaps more acutely focuses on genetic “good” or “desirable” traits. While the word “cultivar” exists internationally, in the United States, the term cultivar is sometimes used interchangeably with “variety.”
The history of artificial selection dates back many thousands of years. It began when people started to develop, plant, and grow major staple crops. They propagated some of the crops that had established themselves for future harvests. Plus, they shared seeds and samples among neighbors and friends. These crop plants included wheat, corn, rice, beans, and other vegetables. Many of these staple crops are known the world over as being key to numerous cultural cuisines. They survived the millennia because a true-breeding (self-fertilizing) seed will be more desirable than a random seed.
There are organizations around the globe that have confirmed certain lines of trees and plants to be true cultivars. Over time, even during the green revolution—when people were making discoveries in gene modification—groups, academics, experts, and governments joined together to develop numerous other cultivars. These selective breeding practices have made it possible for modern cultivar vegetables to be developed and used. From these practices stem advances in the field and a deeper understanding of plant and tree propagation.
To really understand the distinction of a cultivar, think of what you expect when you go to the grocery store and buy a head of cauliflower or broccoli. You can imagine the bunched, bulbous groups that look like miniature trees. These are prime examples of cultivars. Broccoli and cauliflower haven’t always looked like they do now. The same goes for other foods and plants, such as cabbage, kale, kohlrabi, and Brussels sprouts. Farmers and biologists considered their original forms and their best assets and selected them to pass down down the genetic line for better use by humans.
Cloning is actually a better way to propagate further certain plants and trees, such as grapevines, woody ornamental, or fruit trees. This can be done by cutting a small part of the plant and moving it into a growing medium indoors to grow into its own plant. Once the initially small, selected piece is bigger and heartier, it can be replanted outdoors. Cultivars can continue on through their seeds, but they must be kept separate from the original species. Ideally, a plant or tree self-fertilizes, and many grains, vegetables, flowers, and other crops continue this way.
Take, for example, Bing cherries, Rainier cherries, Gala apples, Red Delicious apples. Though these are technically cultivars, they’ve been renamed as brands that produce the same characteristics. That is, Bing cherries have a specific look and flavor, and each year consumers can recognize them. The progeny stays the same through the generations.
Nomenclature can be complex, but plants and trees follow a specific naming format: Species ‘Cultivar name’. For example, the scientific names for Bing and Rainier cherries are the species, Prunus avium, followed by ‘Bing’ and ‘Rainier’, respectively. Gala apples—or Malus domestica ‘Gala’—are a cultivar developed with a certain flavor profile that grows well in specific climates.
Many of the fruits and vegetables you see in your local market are cultivars: sweet potatoes, apples, cabbage, and so on. Ornamental plants also include an array of cultivars, such as daffodils, roses, azaleas, and camellias. Cultivar trees you might come across include the ‘Autumn Blaze’ hybrid maple, ‘Prairie Pride’ hackberry, ‘Macho Amur’ cork, ‘Patmore’ green ash, or ‘Princeton Sentry’ ginkgo. Some of these are prime for urban or small yard planting. These trees have characteristics that make them ideal for planting in narrower areas or smaller, shallower yards. These cultivars differ from their species. They might be thinner, not have seeds, only grow upright, or be adaptable to urban soil.