Rhododendron Family - Part 3: Native Azaleas

Native Azaleas are less in-your-face showy than other members of the Rhododendron family, but they are my favorite. They are native to the US, unlike the popular Popsicle-colored, evergreen Asian Azaleas that are found in many southern landscape plantings.

The Natives are taller and more open than their Asian counterparts. They are deciduous, losing every leaf in winter. In spring, the flowers appear before leaves.  The vivid yellow, orange, red or pink blooms glow like torches in the woodland areas where they occur naturally. Given the proper soil (moist, acidic) and light (morning sun, afternoon shade), they perform well in home gardens also. When not in bloom, they fade into obscurity. They look best when incorporated into a natural area rather than jammed against a house foundation. A mature plant may reach 10 to 15 feet, so site accordingly.

There are more than a dozen species of native Azaleas. Many are fragrant. Clemson University has compiled a useful fact sheet, listing species, colors and bloom times. Find a link to their information by clicking here.

According to Alabama and Auburn University Extensions, there are several hybrid groups that are more heat tolerant than most: Aromi hybrids, Auburn series, Confederate series, Sommerville series, Strickland Azaleas, and Clarence Towe’s selections. My friends in the nursery world recommend ‘Admiral Semmes,’ a yellow-flowered shrub in the Confederate series as a strong performer. I cannot distinguish a Piedmont Azalea from a Pinxter Azalea. Both have pale pink flowers with protruding stamens that are beyond gorgeous. Bees, butterflies, and hummingbirds flock to all the native Azaleas. Unfortunately, they are also a deer favorite.

Plants may be propagated from seed or root cuttings. I have experienced failures with both, so will be content to purchase mine from a garden center. Native Azalea is the state wildflower of Georgia.

This ‘Admiral Semmes’ (a Confederate hybrid) is in full bloom, with flower trusses that would rival its showier cousins, the Rhodies.

Pinxter Azalea. Photo by Jerry King, Reidville, SC.

Close view of an ‘Admiral Semmes;’ flower.

The bud of a Flame Azalea inspired its name, since they look a bit like candle flames. This photo Image by Rebecca Matthews from Pixabay

Rhododendron Family - Part Two: Azaleas

If the south had a signature shrub, it would likely be Azalea. Anyone who has watched the PGA Masters golf tournament at Augusta National or traveled through Charleston, SC in springtime can identify the gorgeous members of the Rhododendron genus known as Azaleas.

Give Azaleas acidic soil with plentiful organic matter and partial shade. They especially like the filtered shade of tall pines, it seems. Too much shade and they won’t bloom; too much sun and the leaves get crispy. Stressed plants are susceptible to damage from lacewing insects. Azaleas have shallow roots, so should be irrigated in hot, dry weather. They will not tolerate drought or constantly wet, boggy soils. They are not heavy feeders, so little fertilizer is needed. The University of Georgia Extension has an excellent bulletin on selecting and growing Azaleas. Read it by clicking here.

A lanky plant can be made more attractive by removing awkward long shoots. To provide better air circulation, plants can be thinned by removing some of the inner limbs. Use hand pruners or loppers for either job. Electric hedge trimmers produce unattractive round blobs. It is best to do any pruning immediately after petals shed, to ensure that you are not removing buds that will become flowers next year. While I see many examples of Azaleas that have been pruned into a tight hedge, this is not the best use of the plant. Allow them to retain their native irregular shapes and they will look more graceful.

Azaleas come in all shades of pink, rose, red , lavender, purple and white. Many have attractive contrasting freckles. When I worked in a plant nursery, my customers’ favorites were pink ‘George Lindley Tabor’ and white ‘Mrs. G. G. Gerbing.’ (The latter is much more attractive than ‘Delaware Valley White,’ which seems to hold onto its spent blooms forever.) In recent years, a personal favorite are the Satsuki hybrid Gumpo (please, NOT Gumbo) Azaleas. Gumpos are dwarf, reaching only two feet. They have dense, evergreen foliage and bloom a little later than the more “traditional” types. They tend to be uniform in size, making an attractive foundation plant.

Azaleas put on an amazing show in April and May, then fade into obscurity the rest of the year — except rebloomers. The best known of these, Encore® Azaleas, have led nursery sales since their introduction. Encores are aptly named, since they rebloom in the fall, although the autumn show is never quite as spectacular as the spring performance. They tolerate more sun than most other cultivars.

Like other members of the Rhododendron family, all parts of Azaleas are toxic to both humans and pets. Deer prefer to munch on new, young, tender shrubs; they exert less damage on older, tougher specimens.

Rhododendron Family - Part 1: Rhodies

Rhododendrons, Azaleas, and Native Azaleas look different from each other, but all are members of the Rhododendron genus. When I first started learning about plants, I found this terribly confusing. It made me think of the Newhart television show from the 1980’s: “Hi, I’m Larry. This is my brother Darryl. This is my other brother Daryl.”

There are more than 800 species in the Rhododendron (pronounced rho-doh-DEN-dron) genus. This huge family can be divided into three main types. Those known as Rhododendrons have large, leathery evergreen leaves and rounded bloom clusters about the size of a softball. To make a distinction, I’ll refer to these as “Rhodies.” Azaleas and Native Azaleas have smaller leaves and may be evergreen, semi-evergreen, or completely deciduous. Rhodie flowers have ten or more stamens; azaleas have five stamens in their funnel-shaped flowers. This week’s blog will focus exclusively on Rhodies. I’ll discuss Azaleas in the next blog.

Growing Rhodies in the hot, humid southeast can be a challenge. One gardener told me the secret to her success: “Plant it low and it won’t grow. Plant it high and it won’t die.” She planted her Rhodies by placing the rootball in a shallow depression, piling a 4-inch volcano of loose mulch on top, and watering abundantly. Rhodies need acid soil with a high humus content and moist but well-drained soil. They absorb water through their leaves as well as their roots, so they prefer overhead irrigation. Take care to soak the entire root zone. This is one shrub that does not perform well with soaker hoses or drip irrigation since the root zone is not uniformly dampened. Water in the morning so that leaves are dry before temperatures drop at day’s end. This will help to prevent fungal diseases.

Rhodies hate heavy clay soils, so amend the planting area with ground bark or peat moss or both. Partial shade or filtered sun is best. They have an affinity for the shade cast by tall pine trees. Too much sun bleaches and crisps the leaves; too much shade means few or no flowers. Avoid planting in windy areas. Fertilizer is rarely needed unless one wants to increase the growth rate. Any fertilizing should be done after blooms fade, using a product that is labeled “for acid-loving plants” like camellias, gardenias, hollies, and hydrangeas. Use particular care in removing weeds, since Rhodie roots are shallow and resent damage from cultivation. Limit pruning to the removal of spent flower heads. Such removal will prevent the plant from trying to form seeds and will result in a stronger plant. A gangly plant can be made more attractive by pinching the growing tips of limbs to force branching.

In the warm southeast, search for heat-tolerant cultivars like ‘English Roseum (light rose flowers), ‘Roseum Elegans’ (lavender pink flowers) and ‘Nova Zembla’ (red to dark pink flowers). These will range in height from six to ten feet at maturity, with an equal spread.

All parts of the plant are highly toxic to humans and pets.

I inherited this Rhodie with the property we bought, so I don’t know the variety. I love her freckles.

The leaves of this Rhodie are not diseased; they are covered with pollen shed by the oaks and pines overhead.