Tom Karwin, on gardening | Name this plant – Santa Cruz Sentinel



Take care of your garden

When you grow your existing plants and install new plants, you can rely on the wisdom of the old ones or your own instincts, but success depends on reliable and up-to-date information.

Basic information is available on the Internet or in garden reference books, both organized by botanical names of plants. Knowing the names of plants in your garden, or that you see in a garden center or catalog, provides access to good information about plants.

This mysterious plant has purple flowers with yellow stamens. The flowers ascend in sequence along the flower stem. (Tom Karwin – Contribution)
This succulent plant has a three-foot spread of unusually sprawling leaves and an eight-foot flower stalk. (Tom Karwin – Contribution)

I am currently researching the name of the plant in my garden, a gift from a friend who did not know its name. This is probably one of the 252 species of agave, but I have yet to find a species with the same combination of leaves and flowers.

If you don’t know the names of your plants and don’t care, you can skip today’s section.

Here is a very brief version of Naming Plants 101, a review for gardeners who know the names of their plants and an introduction for those who wish.

Surprisingly, there are four basic types of plant names.

Botanical names

The ancient Romans began to name plants in an organized manner in Latin, assigning them names that described the characteristics of the plant. After a few centuries of naming many different plants, this approach required multiple words (polynomial names) to provide unique descriptions.

In 1700, French botanist Joseph Pitton de Tournefort was the first to clearly distinguish the genus and species of plants, but by the early 1700s, as explorers brought many new plants to Europe, polynomial names became very long. and difficult.

To solve this problem, in 1753 the Swedish botanist Carl Linnaeus published the binomial system, with only two words to identify the genus and species of a plant. Most importantly, this system provides a brief and unique identifier for each plant. Each name can refer to the most important characteristics of the plant, but can also refer to its natural habitat, discoverer or something else.

The binomial naming system is still in use today, in an evolved form. For example, a botanical name can add a reference to a subspecies or to a variety within a species.

The International Code of Nomenclature for Algae, Fungi and Plants (the title is not fully capitalized, intentionally) provides a set of rules and recommendations for the botanical names of plants. It is called ICN. The International Plant Names Index and World Flora Online use the ICN to maintain lists of plants by genus and species.

Botanical names are always presented in Latin. Genus names are in upper case and species names are not in upper case.

Grower names

Wild plants can be identified only with genus and species names.

Cultivated plants are those whose origin or selection is due primarily to intentional human activity are called cultigens, which includes three categories:

Cultivars: cultivated varieties and hybrids of wild plants (the largest category of cultivigens),

Groups: several cultivars with a common characteristic.

Grex (singular grex): several cultivars with a common heritage (“sister plants”).

The names of cultigens are defined by the International Code of Nomenclature of Cultivated Plants, which follows the standards for botanical names of the ICN. The Cultivated Plants Code includes several principles that cover various forms of cultigens, including genetically modified plants.

Cultigen’s names are always capitalized. Cultivar names must be unique in combination with botanical names and are identified by single quotation marks.

Common names

Most garden plants have a common name that is familiar to many gardeners and easier to remember than botanical and cult names. Common names generally have a long history and reflect the binomial botanical name of a plant, but not the name of the cultigen.

No agency regulates the use of common names, so they are not always unique for a specific plant. For example, different plants may have the common name of Dusty Miller or Hens & Checks.

Common names are in upper case and without single or double quotes.

Trade names

Plant breeders and traders can designate their plants with any name permitted by the trader’s country, but without regulation by the Cultivated Plants Code. The code, however, requires that “trade names are always to be typographically distinguished from cultivar, group and grex epithets”. Trade names are correctly presented in small caps and without single quotes.

This limited overview of plant nomenclature should be useful in interpreting plant names seen in garden books or magazines, print or online plant catalogs, or garden centers.

In a follow-up column, we’ll explore strategies for finding the botanical name of an unknown plant.

Improve your gardening knowledge

To learn more about the world of plant nomenclature, search the Internet for any of the organization names mentioned in this column.

The Cactus & Succulent Society of America will host a live virtual tour, “The 35th Annual Intercity Cacti and Succulent Plant Show and Sale,” at 10 am Saturday. This Southern California event is the largest cacti and succulents show and sale in the United States. To register for this free event, visit For more information on the in-person show, visit

The American Iris Society will present the “Dwarf Bearded Irises: The Three Types of MDBS” webinar at 5:30 p.m. Wednesday. Presenter Tom Waters, President of the Dwarf Iris Society, will discuss the origins, different types and cultural requirements of Miniature Dwarfs (MDBS). This event is free for AIS members. If you are not a member, email to learn how to join the webinar.

The Monterey Bay Iris Society will hold its annual rhizome sale in person on both Saturdays, August 7 and 14, at the Aptos Farmer’s Market, located at Cabrillo College on Soquel Drive in Aptos. Sales continue from 8 a.m. to noon each day. This is not a webinar, but irises are popular garden plants that are very attractive and easy to grow. Now is the time to add irises to your garden. This sale offers a wide selection of plants at great prices, and members of the local iris society (my friends!) Will help you advance your iris gardening knowledge.

Pacific Horticulture rescheduled the webinar, “Garden Allies: The Insects, Birds, and Other Animals That Keep Your Garden Beautiful and Thriving,” with author Frédérique Lavoipierre, at 5 pm on October 19. The publication date of his book has been changed. To register, visit

Enrich your gardening days

You can enjoy your garden more and enjoy more gardening success when you know your plants. This knowledge begins with the full names of the plants.

Enjoy your garden!

Tom Karwin is the past president of the Friends of the UC Santa Cruz Arboretum, the Monterey Bay Area Cactus & Succulent Society, and the Monterey Bay Iris Society, and UC Lifetime Master Gardener (certified 1999- 2009). He is now a board member and garden coach for the Santa Cruz Hostel Society. To view daily photos of his garden, To find an archive of previous gardening columns, visit


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