University of Illinois Extension

Know Your Plants

“Do you ever hear gardeners talking about how well their Echinacea is doing, or pick up a gardening magazine article about shade gardening and find that all the plants are listed by their scientific or ‘Latin’ names,” asks Sharon Yiesla. “Are people showing off their knowledge or are they trying to annoy you? Actually, they are just trying to communicate clearly with others,” says Sharon Yiesla, U of I horticulture educator.

Most plants, she explains, have common names and they are usually easier to pronounce, but they may not be accurate or they may lead to confusion. Some common names may be applied to more than one plant.

“If you mention ‘snowball bush,’ you may be thinking of a certain type of viburnum, while someone else is thinking of a type of hydrangea,” she says. “You can’t really have a meaningful conversation, because you are talking about two different plants.”

More confusion arises, because some plants have more than one common name. Acer saccharinum is commonly called silver maple, but some people know it as soft maple. Liriodendron tulipifera is commonly known as tulip tree, but it can also be called yellow poplar, even though it is not a poplar at all.

For any given plant, the same scientific name is recognized and used world wide.

Sharon Yiesla

“Some common names just don’t make sense,” says Yiesla. “Watermelon begonia is neither a watermelon nor a begonia. It is a Peperomia, a common house plant.
“To avoid such confusion, we use scientific names for our plants. They are more standardized than common names. For any given plant, the same scientific name is recognized and used world wide.”

Every scientific name is made up of two names, the genus and the specific epithet--when used together they tell us the species of the plant.

“Let’s look at an example. The name Quercus alba refers to the tree we commonly know as white oak. The genus, Quercus, is the Latin name for oak. So when we say Quercus, we know we are discussing oaks, but we are being very general,” she says.

“That’s where the specific epithet--the second name--comes in. It defines which oak we are discussing. By adding the specific epithet, alba--which means white--behind the genus Quercus, we form the species name Quercus alba and now we are talking about a particular oak, the white oak.”

The standardization of scientific names helps us be clear about which plant we are discussing, but many people still find these names difficult to understand. Part of the confusion comes from the fact that most people don’t speak Latin. The confusion also partially arises from the fact that some of these scientific names don’t appear to have good “meanings.”

“Many genus names are derived from ancient Latin terms and don’t have what we consider to be a good translation,” explains Yiesla. “Other scientific names are derived from proper names. For instance, Kolkwitzia amabilis--Beautybush--was named for Richard Kolkwitz, a botany professor.

“There are, however, many scientific names that have good meanings and help us know something about the plant.”

Some words used as specific epithets--the second name--refer to color: alba (white), rubra (red), nigra (black), viridis (green), and purpurea (purple). When these terms occur in a species name, they often indicate that some part of the plant is that color.

Other words tell us something about the environment in which a plant thrives. Palustris means “marsh-loving,” indicating that the plant tolerates poorly drained soils, such as Quercus palustris, pin oak, which tolerates heavy clay soils.

Sylvatica means “growing in the woods,” such as Nyssa sylvatica, black tupelo, a forest tree. Nivalis means “growing near snow,” indicating that the plant blooms very early in the season, such as Galanthus nivalis, snowdrops.

Some names tell us the country of origin for a plant. If “chinensis” appears as a specific epithet, then the plant is native to China. “Japonica” indicates a native of Japan and “alpinum” indicates a plant native to alpine climates. Names that refer to states like “viriginica” and “pensylvanica” indicate that the plant is native to North America.

Other scientific names indicate the habit or form of the plant. When “procumbens” is used as a specific epithet, the plant is usually low-growing. “Repens” indicates a plant that creeps, “dendron” a plant that is a tree or is tree-like, “elatum” means tall, indicating the height of the plant, and “gracilis” means slender.

“Knowing the right name can help you obtain the right plant,” says Yiesla. “When you learn the scientific name of the plant, learn the whole name. If you go to a garden center and ask for a Eupatorium you might get Eupatorium maculatum (Joe-pye weed which has pink flowers), Eupatorium coelestinum (hardy ageratum, which has blue flowers), or Eupatorium perfoliatum (boneset, which has white flowers).

“Scientific names can be tricky at first, but as you start to learn them, you will find them helpful.”