You might want to identify an outdoor plant for many reasons. Maybe you're wondering if those berries are toxic to your new puppy, or maybe you need to tackle the best control strategy for those weeds that keep popping up in your garden. Perhaps you want to better understand and connect with the natural world. Whatever the reason, just grab a field guide from your public library to get started.
Plant identification requires few tools to get started. Field guides, many of which are available at the public library, provide illustrations or photographs of plant species, along with descriptions and further information about geographical range, habitat and behavior. Identification keys help you to identify a species by leading you through a series of choices based on your observations of the plant's characteristics. A good key will help you to narrow down the species or at least the family.
Plant identification relies strongly on your powers of observation. Most people begin by describing the shape of the plant's leaf or the color of its flowers. Don't forget to note its size; the arrangement of the leaves and flowers; the presence of any seeds, fruit or cones; and the scent and texture. If you don't want to drag along your field guides, make notes, draw sketches or take photographs. When you have your field guide in hand, your records will help you to distinguish between similar-looking species without second-guessing your memory.
Note any habits or behaviors that you observe. For example, many plants flower for only a short time each year, or leaves change color in the fall. Also note where you saw the plant. When consulting your field guide, make sure that this information matches up. It is unlikely, for example, that a grass that grows at the edges of lakes is what is growing in the vacant lot next door. Confirm that any possible matches occur in your geographical range as well.
Botanical texts, even those intended for laypeople, can sometimes present technical terminology. On his website Backyard Nature, naturalist Jim Conrad suggests the technique of leapfrogging for budding naturalists. Use the glossary of your field guide or key to look up words you don't know. If the definitions also contain words that you don't know, look those up as well. Soon, you will be more comfortable with botanical terminology and better able to decipher whether a description represents your plant.
According to the Botanic Gardens Conservation International, about 400,000 known plant species exist. No field guide or identification key is going to name them all. When you can't find a species, the USDA National Agricultural Library recommends at least trying to identify the family to which the plant belongs. Besides being a possible gateway to locating the species, the family classification may provide valuable information that helps you to better understand the plant you have found.