Identifying plants feels a bit like getting lost in a foreign city. You can state the basic problem: What is this? You're solid on the basics -- you know bud and bloom colors. Then your guide asks about nodes or leaf shape (let alone whether your sheath is pubescent or glabrous) and, without taking a step, you're lost all over again. The tools for practical plant identification appear in elementary school, then tend to vanish until serious college botany classes. Fortunately, an increasing number of practical tools for home gardeners make plant identification more manageable.
To most home gardeners, standard plant taxonomy is a unique combination of Latin, Greek and useless aggravation. While the necessity of being able to distinguish one kind of peony from another may be apparent (and occasionally interesting), a gardener wishes for a system that talks more about planting conditions, disease precautions and overall care. As more than one gardener has fumed, the plant is being acquired for the garden, not for the family tree. On the other side, gardeners learn that distinctions between plant varieties can make a big difference in their use. Friends from across the country discussing "Indian pinks" may eventually discover that a local name describes two completely different plants. Consulting taxonomist Susyn Andrews notes that oil from one variety of lavender makes fragrant perfume, while oil from a similar variety causes heart palpitations. (For her amusing and down-to-earth defense of taxonomy, see Resources.)
Practical Plant Parts
More critical than a full course in taxonomy, knowledge of plant parts facilitates a gardener's discussions with growers and other experts. One good source of a plant-parts vocabulary is your local County Extension service. Whether you enroll in Master Gardener classes or simply request fact sheets, Extension services can provide excellent tools for plant identification, including useful vocabulary. Texas A&M University Extension, for example, publishes an online weed-identification guide that uses and illustrates a large but basic practical plant-parts vocabulary. This vocabulary can be put to good use in describing a mystery plant to "Mr. Smarty Plants," an online service of the Lady Bird Johnson Wildflower Center in Austin, Texas.
A Picture's Worth
When possible, photographs are a good tool for identifying plants. Especially with rare or native plants, photos solve the problem of transporting the plant itself for identification. Ideally, photos capture a plant at more than one stage (in seedling, in growth and in bloom, perhaps even going to seed). From County Extension services to the Lady Bird Johnson Wildflower Center's "Green Guru," botanists working from photographs can often come very close or directly on target in identifying a mysterious plant.
Physical Examination Options
At times, physical examination of a plant is quick and easy to manage. A new weed or a plant displaying an unfamiliar disease, for example, can be packaged according to directions and mailed to one of the sites listed by the University of Oregon Extension's Plant Disease Clinics. Similar clinics, whether publicized as classes or provided as mail-in services, are conducted by County and University Extensions all over the country. Classes and clinics include information about plants referred to as "non-native," "introduced" and "invasive."
The USDA Plants Database can be used online in several ways to identify plants. Nearly all plant fact sheets contain photographs -- often a variety of photos of the plants growing in situ. Searches can be organized by state, natives, environment (wetlands, prairie), common name (blanketflower) and other variables (shade, xeriscape). The National Arboreteum in Washington, D.C. maintains a herbarium, gardens and research facilities. The Arbor Day Foundation maintains photo and data archives on many varieties of trees, along with printed guides for identification.
Identifying an unfamiliar plant may provide just the occasion you have been waiting for to visit your local botanical garden, nature center or native plant garden. Many local organizations possess a surprisingly wide knowledge of regional plants and reliable identification sources. Whether you want something red for that sunny spot on the deck or need to know what's trying to ground-cover your lawn, local centers may be a great place to start.