Whether you saw it on a hike, in a magazine or in your neighbour backyard, using a field guide is the best way to identify a mystery plant. As the name implies, field guides are intended to be used in identifying plant or animal species out in the field. However, as long as you can recall enough information about the shrub, it is not always necessary to have one at hand.
Revisit the shrub. Take note of leaf shape, thickness and arrangement. Sumac varieties have compound leaves, meaning that there are more than one leaflet attached to a single stalk. The aromatic sumac, with clusters of shiny red berries, has only three leaflets on each stalk. Smooth sumac, on the other hand, can have 11 to 31 pinnately compound leaflets that look similar to the branches of a fern. Its berries grow in extremely dense clusters and are covered with sticky hairs. If it is needle-leaf shrub, there is a good chance that it is a Canada yew. The fruit of these common decorative shrubs is actually a seed that resides in a protective cup that looks like a round, red berry.
Look for additional characteristics particular to the plant and write them down. Has it ever flowered? Does it emit an aroma? The red elderberry, or stinking elderberry, develops white flowers in early spring that grow in pyramid-shaped clusters. The shiny berries grow in sprays, or clusters, and the plant gives off a rancid odour when crushed. Indian tribes have been known to use elderberry residue as insect repellent. Small details can make a big difference in narrowing the thousands of plants described in a field guide.
Consider geographic location and time of year. The U.S.Department of Agriculture's plant hardiness zone map categorises trees and shrubs based on their adaptability to annual minimum temperature ranges. Other resources might be arranged by state, region or even country. The smooth sumac is the only shrub that can be found in all 48 contiguous states.
Locate a field guide to trees and shrubs in your area. Libraries and small bookstores will have these on hand from a number of different publishers. Keep in mind that trees and shrubs are typically grouped together in a single guide. The main difference between the two is that shrubs are typically less than 13 feet in height and have several perennial stems that extend from the base.
If time is an issue, there are a number of electronic field guides available on the internet. eNature offers an easy-to-use electronic wildlife guide that has carefully reviewed information on over 6,000 plant and animal species. The visual search engine allows you to narrow shrubs by leaf type, fruits and nuts, habitat and region. Use the information you have collected and narrow the possibilities. Like most plants, shrubs are primarily separated into deciduous species that lose their leaves in the winter and evergreen varieties that do not.
Never ingest fruits or berries from a plant unless you can make a positive identification. Even then, consume only small amounts at a time until you are sure that your body doesn't react. Be careful when handling the plant, especially if you are still unfamiliar with it. Some species may have small thorns or a poisonous coating that can cause an allergic reaction.