Rhododendron: Rivals of the Rose

rhododendron med

“Rhodora! if the sages ask thee why

This charm is wasted on the earth and sky,

Tell them, dear, that, if eyes were made for seeing,

Then beauty is its own excuse for being ”

— Ralph Waldo Emerson, “The Rhodora” in “Poems,” 1847

In May of 1834, Ralph Waldo Emerson began a new journal while visiting his mother in Newton, Massachusetts. No doubt inspired by the profusion of flowers in bloom at the time, his first entry was “The Rhodora,” a verse that was later published in his first book of poetry.

Emerson subtitled “The Rhodora” with “On being asked, Whence is the flower?” and he ended the poem by answering this question:

“Why thou wert there, O rival of the rose!

I never thought to ask, I never knew:

But, in my simple ignorance, suppose

The self-same power that brought me there brought you.”

“The Rhodora” is an early expression of Emerson’s thoughts about the connection between humans and nature, ideas he developed further in his well-known transcendentalist essay “Nature” (1836).

It’s certainly not difficult to understand why Emerson saw a higher power in the brightly colored rhododendron flowers, or why he described them as a “rival of the rose.” In fact, “rhododendron” comes from the Greek “rhodon” (rose) and “dendron” (tree), perhaps originally referring to Rhododendron species that can grow as tall as trees.

The ancient Greeks and Emerson may have been surprised to learn there are about 900 species in the Rhododendron genus that have originated in many parts of the world, a few of which are China, Japan and the United States.

The Rhododendron genus includes evergreen and deciduous rhododendron and azalea species. The two types of plants are typically distinguished by the number of stamens in their flowers: rhododendrons have 10 or more stamens, and azaleas have two stamens.

North America has 28 native species of rhododendron, most of which grow in the northeastern and southeastern States. In the Pacific Northwest, there are three native rhododendron species — two rhododendrons and one azalea.

R. albiflorum is a white or yellow-flowered rhododendron that grows wild at higher elevations, but it resents transplanting and is difficult to grow in gardens.

Much more amenable to cultivation is our native Rhododendron macrophyllum, a rhododendron species that can grow up to 24 feet tall in shadier sites. The shrub/small tree keeps its large, leathery, light-green leaves for 2-3 years before replacing the foliage. Commonly called the Pacific rhododendron, R. macrophyllum bears many clusters (also called trusses) of pink, bell-shaped flowers during April and May.

A particularly garden-worthy native is R. occidentale, or western azalea, a deciduous species that has fragrant, white flowers tinged with pink and gold and reaching 5 inches across. The shrub can grow up to 10 feet tall.

However, most of the rhododendrons blooming in our area right now are among the 20,000 rhododendron and azalea hybrids that have been cultivated before and since Emerson wrote “The Rhodora.” Rhododendron species are easily crossed, so evergreen and deciduous cultivars are available in a plethora of colors, sizes, fragrances, cold hardiness, heat tolerance and pest resistance.

Gardenia, a garden design website (www.gardenia.net), recommends R. occidentale as well as a number of rhododendron hybrids for the Pacific Northwest region that have earned recognition by the American Rhododendron Society:

? R. ‘Christmas Cheer’ – early-spring bloom; long-lasting pink flowers; evergreen; drought tolerant

? R. ‘Dora Amateis’ – mid-spring bloom; compact; white, scented flowers; evergreen

? R. ‘Gibraltar’ (azalea; mid-spring bloom; bright orange, frilled flowers; mildew-resistant; deciduous

? R. ‘Girard’s Fuchsia – azalea; mid-spring bloom; vibrant purple; narrow, glossy leaves; semi-evergreen

? R. ‘Hino Crimson’ – azalea; mid-spring bloom; compact; scarlet-red flowers; shiny, dark-green leaves turn bronze in winter

? R. ‘Homebush’ – late-spring bloom; round clusters of rose-pink, semi-double flowers grow on tips of upright branches; deciduous foliage provides fall color; mildew-resistant

? R. ‘Ken Janeck’ – mid-spring bloom; compact, multistemmed, mounding growth habit; pink, frilled flowers; dark, evergreen leaves

? R. ‘Mary Fleming’ – mid-spring bloom; compact; creamy, wavy-edged flowers tinged with pink; small, dark-green leaves turn bronze in fall; evergreen

? R. ‘Percy-Wiseman’ – mid- to late-spring bloom; rounded growth habit; flowers pass through shades of creamy white to red, pink and purplish-pink for long-lasting display; glossy, dark evergreen leaves)

? R. ‘PMJ Elite’ – mid- to late-spring bloom; vigorous bloomer; vibrant, reddish-purple flowers; glossy, dark evergreen leaves turn reddish-purple in fall

? R. ‘Ramapo’ – early to mid-spring bloomer; exceptionally cold hardy and heat tolerant; compact; light violet-purple flowers; fragrant, evergreen leaves

? R. ‘Rosebud’ – azalea; mid- to late-spring bloom; compact; vigorous bloomer; rose-pink double flowers; evergreen

? R. ‘White Lights’ – azalea; late-spring bloomer; abundant pale-pink, fragrant flowers; deciduous leaves turn bronze in fall

? R. luteum (pontic azalea) – late-spring bloomer; bushy growth habit; bright, golden-yellow, scented flowers; deciduous foliage turns colors in fall

? R. schlippenbachii (royal azalea) – mid- to late-spring bloomer; fragrant, saucer-shaped, light pink flowers grow on branch tips; deciduous foliage turns bronze in fall; well-balanced, branching structure creates winter interest

Whatever rhododendron species or hybrid is selected, it will need the right growing conditions to thrive. These include: partial or dappled shade, moist, acidic soil (pH 4.5-5.5) with lots of organic matter, good drainage, wind protection and mulch to protect the plant’s shallow roots.

After removing a nursery-bought rhododendron from its container for transplanting, look for roots that have grown into a thick mass. Make vertical slits through the root mass with a knife and tease apart with your fingers. Water the root ball before planting, then add compost, more water and a top layer of mulch.

Keep in mind that nursery-grown rhododendrons have most likely been forced to bloom for selling purposes; don’t be surprised if your transplanted Rhodie skips a year before blooming again.

Pruning rhododendrons is usually unnecessary, other than removing dead or damaged branches; however, deadheading the faded flowers will encourage new growth.

To rehabilitate large, overgrown rhododendrons, cut the branches 6-12 inches above the ground right above a latent bud or bud cluster, add compost and mulch, and keep the plant roots moist but not wet.

Common problems with rhododendrons can usually be traced to improper placement and inadequate growing conditions, particularly soils with poor drainage that can lead to root rot, powdery mildew, leaf spot and other diseases. Weakened shrubs are also more susceptible to invasions of insect pests, such as aphids, borers, leaf miners and white flies.

It’s important to note that all parts of all types of rhododendron are poisonous to humans and pets (also horses). The toxicity of the plant is probably why it represented “danger” in the Victorian language of flowers. There have been cases of accidental poisoning when people consumed “mad honey,” which contains a neurotoxin from rhododendron nectar.

Ralph Waldo Emerson most likely was unfamiliar with the rhododendron’s hallucinogenic effects, yet he saw God in “the purple petals, fallen in the pool, [that] made the black water with their beauty gay.”

Rhonda Nowak is a Rogue Valley gardener, teacher and writer. Email her at Rnowak39@gmail.com. For more about gardening, visit her blog at http://blogs.esouthernoregon.com/theliterarygardener/ and check out her podcasts and videos at https://mailtribune.com/podcasts/the-literary-gardener, and her website at www.literarygardener.com.

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