Spring is incomplete without the bold and soft hues of azaleas in your home garden. These spectacular plants are prevalent and have dominated yards and countless gardens in North America. These plants originated in Asia and made their way to the US via Europe around two hundred years ago. Since then, according to the American Azalea Society (ARS), over 10,000 different cultivars, or cultivated varieties, have been registered or named. The high demand for cultivated azalea can be attributed to its small manageable dwarf sizes, diverse attractive colors, deep green leaves year-round, and adaptability to the climate, making them easy to grow.
However, there are equally beautiful native azaleas in North America that are seldom seen in home gardens and are still not as well-known as their Asian cousins. To find them, it would be best to wander from the landscaped yards into the woods. In this post, I talk about the extraordinary beauty and ecology of native azaleas, as they require more attention and care from the gardening community.
What are native azaleas?
Azaleas are members of the heaths (Ericaceae) plant family, which includes cranberry, blueberry, and huckleberries. Because there is often confusion among people between azaleas and rhododendrons, it is much easier to remember that all azaleas are rhododendrons, but that all rhododendrons are not azaleas. In fact, azaleas belong to the genus Rhododendron. Azaleas native to North America are usually medium-sized or tall shrubs with soft, deciduous leaves, funnel-shaped flower lobes, and long tubular flowers with stamens extending beyond their showy petals. There are eighteen North American native azaleas (visit the American Azalea Society and American Rhododendron Society to learn more).
Why grow native azaleas?
Native azaleas display shades of white, orange, pink, red, and yellow throughout the spring and summer. Although most people associate azaleas with spring, several native ones bloom in mid and late summer. It is often noticed that azaleas in their natural habitat show some staggering in their flowering timing, and their flowering durations usually range between 15 to 20 days. So, if you carefully select species based on their flowering timing, you can have azaleas bloom in your home gardens for at least four to five months. Unlike the evergreen cultivated ones, native azaleas have exceptional fall color before they shed their leaves for winter. Most native Azaleas can reach heights of 4’-8’ and can be used in hedgerows and as the background to other flowering dwarf shrubs. Some of the common native azaleas in the woodlands of Maryland, Virginia, and DC are smooth azalea (Rhododendron arborescens), swamp azalea (Rhododendron viscosum), pinxter azalea (Rhododendron periclymenoides), coast azalea (Rhododendron atlanticum) and early azalea (Rhododendron prinophyllum).
Besides the colorful hues in your green space, growing azaleas will also help maintain the native pollinator network in your local environment. Native azaleas can sustain a variety of fauna through their flowers; they are attractive to bees, butterflies, moths, and hummingbirds. The quantity and quality of nectar and pollen among these plants are often observed to be higher than in the cultivated ones. In general, they have a high amount of concentrated nectar and string-like pollen threads that help attract myriad forms of floral visitors native to North America.
Some azalea species have attractive warm orange and red flowers, and birds can detect warm colors easily. At the same time, insects, including bumblebees and smaller bees (e.g., Andrena sp.), are attracted to light pink, purple, and white palettes. Certain native species, such as sweet azalea and piedmont azalea, have a strong sweet fragrance. Besides providing a sweet smell, their fragrance also helps attract night pollinators such as moths. Nectar volume among the azalea flowers is relatively low compared to its nectar concentration; therefore, the migratory ruby-throated hummingbird makes occasional visits, as birds usually prefer flowers with high voluminous nectar. Their unique floral characteristics also attract diverse butterflies, recognized as potential pollinators for these species. Commonly observed butterflies are eastern tiger swallowtails (Papilio glaucus), silver spotted skippers (Epargyreus clarus), and great spangled fritillaries (Speyeria cybele). The flapping of butterfly wings helps transfer pollen from the male to the female organ and facilitates successful reproduction in these plants. Therefore, growing different shades of native azaleas in your yards and home gardens will be a good idea to support native pollinators.
Native azaleas are also relatively free of pests and diseases compared to cultivars, making them low-maintenance plants. They do not require regular pruning and are moderately slow growers. However, knowing the ecology of these species may be helpful for plant growers. For example, in the forest, these plants are mostly found as an understory of other tall hardwood trees like oaks and chestnuts; therefore, they will do well in less light and shaded areas in the home gardens. Most of them require moisture with good drainage and humus-rich acidic soil. You can learn more about the detailed requirements of the conditions preferred by these plants at the American Azalea Society.
It is never too late to add these cool plants to your home garden.
By Shweta Basnett, Fulbright Postdoctoral Fellow, Department of Entomology, University of Maryland. Visit her website for more information about her current research.