Japanese honeysuckle, or Lonicera japonica, is a perennial woody vine with Asiatic origins, as its name implies. American honeysuckle, or Lonicera americana, is also a climbing, woody vine that belongs to the same honeysuckle family but is less invasive than its Japanese cousin. The two have distinct differences you can identify yourself.
Look at the leaves. Japanese honeysuckle has pairs of two leaves directly opposite each other, 2- to 3-inches long, oval and semi-evergreen. American honeysuckle leaves are also paired, semi-evergreen and oval, but slightly smaller, at 1 to 2 inches.
Check the flowers. If the honeysuckle is in its flowering stage, the two plants produce very different flowers. Japanese honeysuckle has finger-like petals on two opposite sides of the flower, which are white and fragrant, and occur in pairs. American honeysuckle flowers are more colorful, ranging from cream to pink and even occasionally yellow. Their petals appear in elongated whorls around a center and are also very fragrant.
Look for any fruit. If it's late summer, the fruits also appear different. Japanese honeysuckle bears black berries that are small, shiny and close to the stem of the vine. American honeysuckle has orange, round berries.
Look at the overall vine. Older, established Japanese honeysuckle stems are brown and often have peeling strips of bark. They are also hollow when cut across with a knife. American honeysuckle stems remain green and flexible, unless dying.
Check with an expert. If still in doubt, take a sample of the plant to a nursery or county agricultural extension office for identification. There are several hybrid honeysuckles in the United States that an expert may be able to tell you more about.