Flowers in the honeysuckle genus (Lonicera) and the azalea genus (Rhododendron) are popular garden plants grown for their showy tubular blooms and lush foliage. Though the plants share many similarities, there are also a number of differences between the two types of plants that can help you to choose which one is best suited for your garden.
Azaleas tend to grow as large shrubs, whereas honeysuckles are more frequently seen as dense, spreading and trailing vines. Azaleas reach an average height of 10 to 15 feet and may be pruned to give the plant a more hedgelike appearance. Honeysuckles grow outwards or upwards depending on how they are trained, and usually need support from a structure or larger tree. Honeysuckles may grow just a few feet or over 30 feet, depending on the variety. An azalea makes an excellent specimen shrub or privacy hedge, while a honeysuckle is better suited to a trellis, gate or fence.
Many species of honeysuckle and azalea share similar looking tubular flowers. Azalea flowers, however, tend to be showier and more open and are often larger than honeysuckle flowers. They have long, thin stamens that pop out from the petals. Honeysuckle flowers tend to be narrow and thin, although in the case of the Japanese honeysuckle (Lonicera japonica), the flowers have more of a square shape. While a few azalea species are fragrant, like the swamp azalea (Rhododendron viscosum), most species are not fragrant or not nearly as fragrant as the strong, rich-smelling honeysuckle. Honeysuckle plants have more wildlife value, especially with species like the coral honeysuckle (Lonicera sempervirens), which attract hummingbirds and butterflies with its flowers and songbirds with its fruits.
Azaleas do not grow nearly as vigorously as honeysuckles do, and as a general rule are much less likely to be invasive. Japanese honeysuckle can be highly invasive and is listed as a "severe threat" to native plant life in Tennessee. It is not recommended for Florida or states that receive heavy rainfall. While there are many species of both honeysuckle and azalea that are native to the Northern Hemisphere, honeysuckles tend to have a wider range than azaleas. Many honeysuckles will grow through USDA zones 4 or 5 to 9 or 10, while azaleas are less able to handle frosts and extreme heat and tend to do better in 5 to 9.