Inevitably, we encounter plants without knowing what they are, i.e., we don’t know their names. That’s hardly surprising because there are so many different plants. When botanists count the flowering plants, called angiosperms, which we appreciate in our gardens, they identify nearly 300,000 species in over 13,000 genera. That total does not include the growing numbers of cultivars of the more popular species.

Many gardeners, much of the time, simply don’t care to know the name of a plant that they enjoy. It’s enough to have the plant produce colorful blossoms and attractive foliage and to refer to it by the color of its flowers, its location in the garden, or a characteristic of its form or foliage.

When a better name is needed, gardeners often find the genus to be sufficient: it’s a rose or an iris or a daffodil.

Still, we sometimes want to identify the plant by its botanical name (genus + species) and its cultivar name. That level of detail has benefits:

• allows the gardener to distinguish between a given plant and other similar plants, e.g., referring to a particular rose within a collection of roses by name, instead of pointing;
• supports research into the plant’s origin, cultivation needs, and propagation methods, in the interest of growing the plant successfully, or shopping for similar plants;
• satisfies the need that some gardeners experience to have a name for each plant.

Finding a plant’s correct name can be challenging. It helps if the gardener enjoys The Search.

Let’s consider broad categories of searches for a plant’s name: the gardener knows (or might know) the plant’s genus, the gardener knows (or might know) the plant’s common name; and the gardener has no information at all about the plant.

Given the plant’s genus, finding the species and ideally the cultivar might begin with a plant reference book, such as Sunset’s “Western Garden Book,” or the American Horticultural Society’s “A to Z Encyclopedia of Garden Plants.” Another approach involves searching the Internet. Wikipedia, which holds information on nearly all plant genera, is a valuable resource for such searches. Browse to Wikipedia (en.wikipedia.org), enter the genus and scroll to the list of species. Whether using a book or the Internet, identifying the species of a given plant requires reviewing the options and deciding which aligns with the features of the plant in question.

Another option is the National Gardening Association’s searchable Plant Database (garden.org/plants/, which includes some 728,000 plants.

When the gardener knows the plant’s common name, some reference books will include a list of common names with links to the botanical names. Still, searching the Internet for the common name is the easier approach.

For the more popular garden plants, search the Internet for the respective society and look on its website for a searchable list of cultivars. Good examples include the American Rose Society, the American Iris Society, and the Pacific Bulb Society. There are many other such societies. Visit the website of the American Horticultural Society and search for “societies by plant type.”

On occasion, the gardener will have absolutely no information about a particular plant and wants to identify it.

Fierce Lancewood

That situation arose recently when a reader sent a photo of a strange-looking plant. In such cases, I draw upon the collective knowledge of participants in the National Gardening Association’s Plant ID Forum, which is a free resource.

To my delight, the Forum participants soon identified the plant as Pseudopanax ferox (Fierce Lancewood, or Toothed Lancewood), which is native to New Zealand. I soon learned about the plant by searching for it on the Internet.

With a little research, you can identify the mystery plants in your garden.