Getting to Know Garden-Speak

By The National Gardening Association, Bob Beckstrom, Karan Davis Cutler, Kathleen Fisher, Phillip Giroux, Judy Glattstein, Michael MacCaskey, Bill Marken, Charlie Nardozzi, Sally Roth, Marcia Tatroe, Lance Walheim, Ann Whitman

The language spoken in gardening circles can be quirky. For example, dirt isn’t just dirt, it’s soil. Dirt is what you make mud pies with. Soil, on the other hand, is full of promise and good nutrients. And some gardenholics tend to go on and on about plant names. You may catch them at the nursery asking, “Which Latin name is most correct, the old one or the new one?” And some gardening terms can sound downright scary, as in “Watch out! That fertilizer is chelated!

It’s not just Pig Latin

Knowing something about plant names helps you appreciate gardening more and can prevent confusion. For example, what you know as a forget-me-not (Myosotis) may be an entirely different plant from what your neighbor claims is a forget-me-not (Cynoglossum). You’d both be right, because you’re each using the common name for the plant, not the scientific name.

Botanical names

The proper (scientific) botanical name of a plant consists of two parts, much in the same way that people have a first and a last name. However, in plant language, the last name comes first.

The most important name is the genus — the “Smith” of Joe Smith, if you will. A genus is a group of closely related plants. Just as in your own family, some of the plant cousins look very much alike, while others don’t bear much resemblance at all. And some plants in the same genus may have different climate preferences. (The genus name always begins with a capital letter when used as part of a multipart name.)

The second name, the “Joe” part of Joe Smith, is the species name. The species name usually describes some feature of the plant or its preferred habitat, or serves as a tribute to whoever discovered the plant. But the species name is disguised in pseudo-Latin, of course, just to keep things interesting. Consider, for example, Hosta undulata. Hosta is the genus name. The species name, undulata, describes the undulating shape of the leaf.

The plain, old-fashioned, natural species of some plants acquire new status in the face of prodigiously hybridized plants — tulips, for example. In those cases, the norm for the plant is some kind of hybrid of indeterminate botanical origin. That’s why when gardeners finally have in their gardens an actual natural, nonhybridized type of tulip, they say something like, “And this is my species tulip.” (You’ll see the abbreviations sp. for species and spp. for its plural.)

Occasionally, a third name follows the species name — the variety. Varieties are members of the same species but are distinctive enough to deserve their own name, which is preceded by the abbreviation “var.” in roman type — for example, Rosa gallica var. officinalis.

Another part of a botanical name is the “cultivated variety,” or cultivar. Whoever discovered or created the plant decided that it was special enough to have its own name. And the cultivar is also special enough to be maintained by cuttings, grafting, line-bred seed propagation, or tissue culture. The cultivar name, which appears after the species or variety name, is the only part of the botanical name that isn’t in italics but is always enclosed with single quotation marks. For example, Lychnis coronaria ‘Angel’s Blush’.

Common names

Of course, ordinary people don’t go around using long Latin botanical names in everyday conversation. Instead, they use a sort of botanical nickname, called a common name. Common names are less formal and easier to pronounce than botanical names. They’re also less precise.

Often, the common name describes some distinguishing characteristic of the plant. For example, the plant called blue star has, well, starry blue flowers.

Finding that several unrelated flowers share the same common name isn’t unusual at all. Unfortunately, regular English flower names are often just as silly as their highfalutin Latin cousins, if for different reasons. For example, two distinct plants share the name “mock orange,” and at least five different plants go by “dusty miller.” At least three unrelated perennials are called coneflowers: Echinacea purpurea, flowers in the Rudbeckia genus, and those in the Ratibida genus. On the other hand, many plants have no common name! Go figure.

The long and short of it is that you need to pay some attention to plant names — if only to avoid buying and planting the wrong plant.

Fertilize by number

When you buy a commercial fertilizer, its analysis appears on the label with three numbers. These three numbers are helpful because they let you know the amounts of nutrients (N-P-K) that are in a particular fertilizer. For example, a 100-pound (43 kg) bag of 5-10-10 fertilizer consists of 5 percent nitrogen (5 pounds, or 2.3 kg); 10 percent phosphorus (10 pounds, or 4.6 kg); and 10 percent potassium (10 pounds, or 4.6 kg). Altogether, the bag has 25 pounds of plant-usable nutrients. The remaining 75 pounds (34 kg) usually consists of only carrier, or filler. A small amount of the filler may contain some plant-usable material.

Any fertilizer that contains all three of the primary nutrients — N-P-K — is a complete fertilizer. The garden term complete has its basis in laws and regulations that apply to the fertilizer industry: It doesn’t mean that the fertilizer literally contains everything that a plant may need.

You don’t need a degree in botany to have a lovely garden. But you do need to understand some fertilizer terminology:

  • Chelated micronutrients: These compounds bind to certain plant nutrients and essentially deliver them to the plant roots. Nutrients that plants require in minute quantities — such as iron, zinc, and manganese — are often available in a powder or liquid chelated form.
  • Foliar: You apply these liquid fertilizers on a plant’s leaves, and the leaves absorb the nutrients directly. Although a plant’s roots also can absorb the nutrients in most foliar fertilizers, those absorbed via leaves have a quick effect.
    Don’t apply foliar fertilizers in hot weather because leaves can become damaged.
  • Granular: These fertilizers are the most common and most often sold in boxes or bags. Most granular fertilizers are partially soluble. For example, a 10-10-10 granular fertilizer is best applied to the soil about a month prior to planting in order for the nutrients to be available at planting time. You also can get special formulations, such as rose food or azalea food. These specialized fertilizers supply nutrients over a longer period of time than liquid or soluble fertilizers but not as long as slow-release kinds.
  • Liquid: Some fertilizers come as liquid in bottles and jugs. On a per-nutrient basis, liquid fertilizers are more expensive than most dry fertilizers. Most liquid fertilizers need further dilution in water, but a few are ready-to-use. Liquid fertilizers are easy to inject into irrigation systems, which is the reason many professional growers prefer them.
  • Organic: These fertilizers are often made from dead or composted plants and animals. As a general rule, half the nutrients in organic fertilizers are available to plants the first season.
  • Slow-release: These fertilizers release the nutrients that they contain at specific rates in specific conditions over an extended period, some as long as eight months. Slow-release fertilizers are very useful for container plants that otherwise need frequent fertilizing.