The plants are trying to tell us something — if only we’d learn their official language, botanical Latin.
“I am the Allium with just one leaf,” says Allium unifolium. (Get it?)
“I am the juniper that carpets the ground,” says Juniperus horizontalis (whose alternate name, Juniperus prostrata, nails its appearance, too).
And Aster alpinus chimes in: “My ancestors hailed from above the timber line — you know, like, the Alps. I won’t appreciate some sodden, clayey spot in your garden.”
Not all plant names offer such easy clues about traits like appearance, preferred conditions or place of origin. It’s worth digging deeper, though, and I’m grateful to several formally trained old-school horticulturists, my first garden teachers, who used botanical Latin confidently.
Now, a recent book called “The Gardener’s Botanical: An Encyclopedia of Latin Plant Names” is nudging me to sharpen my skills. The author, Ross Bayton, earned his doctorate in plant taxonomy at the University of Reading and the Royal Botanic Gardens, Kew, in England, and is now the assistant director of the public Heronswood Garden in Kingston, Wash.
Dr. Bayton learned his first botanical Latin word around the age of 11, from his mother’s beloved sweet peas, Lathyrus odoratus, a plant she grew every year.
“I realized that odoratus meant fragrant, and then I saw that word on other plant labels in my own garden, like Viola odorata, Galium odoratum,” he recalled. “And that kicked it all off for me.”
In his garden, he then connected the dots of mollis, for soft (Acanthus mollis, Alchemilla mollis), and its opposite, spinosa, for spiny (Acanthus spinosus, Aralia spinosa). Now they join odoratus among the 5,000-plus entries in his illustrated dictionary.
Our proposal: A little botanical Latin self-study might make better use of some of your garden off-season hours than rewatching that TV series you already rewatched (although I may do that, too). A plant’s Latin name is the only way to know for certain what you’ll be getting when you buy plants in the spring, as common names vary by region — but you have to know how to decode some of the words.
Start with the plants in your garden, Dr. Bayton suggested, or even just learn to address your houseplants by their proper names.
This course delivers a bracing memory-fitness test, and a bit of a treasure hunt. Give in to the arcane, and be empowered: Get to know your plants, and the sometimes-nerdy snippets of the history of our human relationship with them, too.
Don’t Worry: There Won’t Be an Oral Exam
And you won’t be tested on pronunciation.
“It’s not the language spoken on the streets of ancient Rome,” said Dr. Bayton of the naming system formalized in 1753 by Carl Linnaeus. “It’s based on that, but incorporates much ancient Greek and exists primarily as a written language.”
Gardeners on different continents pronounce Latin names in different ways. And while there may be an “official” way (as Dr. Bayton lists in the book), he added, “say them however you want, and most gardeners will understand you. And when searching for plant-care information online or in books, pronunciation is irrelevant.”
What’s In It for Gardeners?
“Accuracy — knowing a plant’s correct name — is the key to finding out everything about it,” said Dr. Bayton, who offers the common name bluebell as one example of inaccuracy’s slippery slope.
Which bluebell? The native Eastern wildflower Mertensia virginica or Hyacinthoides non-scripta, a bulb from Western Europe and England? The Campanula referred to as Scottish bluebell, or the Australian, Texas or California bluebells, each in a different genus?
Unlike common names, which can be shared by multiple plants and vary regionally, the Latin name is universal.
But even when we know the genus, let’s graduate beyond “my hydrangea” to the other word in the Latin binomial, the species name or specific epithet that modifies it. Let’s get to Hydrangea quercifolia (translation: the hydrangea whose leaves resemble those of an oak, oaks being genus Quercus), helping discern it from Hydrangea paniculata (whose leaves don’t).
“Hydrangeas are a big group, and they don’t all need the same treatment,” Dr. Bayton said. “If you want to know how to prune one, there are four distinct ways — so knowing it’s a hydrangea isn’t enough information.”
(Speaking of which, here’s a pop quiz, or a trick question: What’s the common name of the genus Hydrangea? Answer: There isn’t one. “What allows a name to skip over that botanical Latin barrier and not be feared?” Dr. Bayton said of the list of plants like this, which includes Magnolia, Rhododendron, Camellia, Iris, Fuchsia and Begonia. “A handful of iconic garden plants have names that are easy to pronounce and spell, and are so widely used that they’re devoid of dread.”)
Sometimes, imprecision can be not just inconvenient — the wrong plant ordered, a plant incorrectly pruned — but potentially dangerous, he said. Although Castanea (the true chestnut) and horse chestnuts (Aesculus) share that one key word in their common names and also some traits (both are deciduous trees bearing spiny fruits), they are not related, and the latter’s fruits, also called buckeyes, are poisonous.
What’s in a Name?
Most Latin names are descriptive — sometimes vividly so. Toxicodendron (the genus of poison ivy, oak and sumac) and Urtica (stinging nettles; Urtica means “to burn”) spell danger: toxicity or the risk of urticaria, a skin rash.
A species name might reveal a slightly less terrifying trait, such as flower color. Yellow may be flavus or luteus, citrinus (lemon-colored) or aureus (gold). Silver is argenteus. Red is rubrum, as in the red maple (Acer rubrum); rosy-pink, roseus. Blue shades include azureus (sky) and darker caeruleus. Purple is purpureus. White is albus; black, nigrum (black pepper, Piper nigrum).
Native habitats might instead be called out by descriptors like sylvatica (of the woods) or palustris (marshland), maritima (seaside) or aquatica (in water).
Some plants speak of their geographic origins. Various Eastern North American natives bear the epithets canadensis or virginiana. But occasionally this backfires: Scilla peruviana doesn’t hail from Peru, although it did travel from its southwestern European or northwest African homeland on a ship named Peru, Dr. Bayton said, confusing the botanist who named it. The rules of botanical nomenclature say the oldest valid species name sticks, so it is peruviana evermore.
There is even the occasional anagram, where an existing genus name is remixed to form a new, botanically related one: Saruma is a cousin of the more familiar Asarum, like the native ground-cover ginger, Asarum canadense.
“Sometime taxonomists are just having fun with us,” Dr. Bayton said. “Like the one who named a cactus genus from Argentina Denmoza, because it comes from the province of Mendoza.”
Eponymous Names and Language Bias
A subset of plant names — both genus and species — are commemorative, honoring the explorer who discovered them, or perhaps the person who funded the mission during which they were found.
“There are plants named after politicians, after botanists, after botanist’s wives,” Dr. Bayton said. “So while the information contained in Latin names isn’t always directly helpful to the gardener, there are a lot of fascinating stories in it that explain how the world was explored and how plants were discovered.”
No surprise that they tilt heavily toward the European, where the system had its origins. Frequently honored collectors include the Scottish botanist David Douglas (the epithet douglasii, and also Douglasia, a genus of Western North American primrose relatives). The prolific British explorer Ernest Henry Wilson, who sent back thousands of plants from China, is noted by wilsonii (a Magnolia and a Picea among them), and Augustine Henry, an Irish plantsman, by henryi (including Lilium henryi).
Occasionally a local name was used, as with the Asian native plants Fatsia (from the Japanese for eight fingers, descriptive of the leaves’ lobes) and Kirengeshoma (for the Japanese words for yellow, lotus blossom and hat, describing its flowers). Catalpa sounds like botanical Latin, but it is actually an Indigenous North American name for a tree genus that includes two American species.
Women, too, are markedly underrepresented.
“A lot of both the men and, especially, women honored are aristocrats or royalty,” Dr. Bayton said. “But it’s considerably rarer to find a working woman so honored.”
Clivia was named for the Duchess of Northumberland, Charlotte Percy (nee Clive), the first person to bloom that South African plant brought back to England. The newly crowned Queen Victoria inspired an eponymous genus: Tropical waterlilies from the Amazon were named Victoria amazonica and put on display in the Crystal Palace in Hyde Park, London.
By contrast, Mathiasella, a plant Dr. Bayton included in the book and grows at Heronswood, honors Mildred E. Mathias, a California botanist who earned her doctorate in 1929 and in 1964 became the first woman president of the American Society of Plant Taxonomists. A botanical garden on the U.C.L.A. campus is also named for her.
So why not rename those that are not politically correct? The result would be taxonomic chaos.
“Today, I would rather not see plants named after some foreigner who came in and named them, when the plants were always known by the people who lived there,” Dr. Bayton said. “I am increasingly uncomfortable with that.”
With new introductions, he said, we should give them a local name, or just describe them with the chosen Latin name.
One that can help the gardener who eventually grows them.