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Potomac Valley Chapter
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American Rhododendron Society
Newsletter: Summer 2005

Next Meeting: September 18, 2005

Our next meeting is scheduled at the National Arboretum Administration Building on Sunday afternoon, September 18, 2005. Refreshments and socializing will start at 1:00, the business meeting at 1:30, and the program at 2:00 PM. Guests are always welcome, so please invite a friend.

Don Hyatt will present a slide program on “Landscaping for the Shady Garden”, a humorous look at his 50 years of gardening in the shade with rhododendrons, azaleas, and companion plants.

Fall Banquet: October 22, 2005

Our Fall Banquet to be held at JR’s Stockyards Inn at Tyson’s Corner on Saturday, 10/22/05, from 4:30 to 8:00 PM. Same menu as before, prime rib or salmon, and cost per plate is $35. Registration forms are with this newsletter. Please make sure we have your reservation by October 15. You may write one check for banquet fees and membership dues, but we cannot accept credit card payments.

Our evening speakers will be the entertaining husband and wife team of Rick Ray and Liz Ball from Springfield, PA. Rick and Liz, renowned horticulturists and expert photographers, will give a dual talk titled “Merger Madness.” Don’t miss this humorous account of how two experienced gardeners decided to marry, and then had to tackle the challenge of establishing a new 2-acre garden at their new home. Laugh at how a plant collector and a gardener have managed so far to reconcile two very different approaches to horticulture.

Chapter News:

Potomac Valley Chapter Elections
At the chapter picnic at Margaret White’s house on June 21st, we elected new officers. Please give our new leaders your full support.
President: Jon Wallenmeyer
Vice President: Bob McWhorter
Treasurer: Phyllis Rittman
Secretary: (still open...)
Van Veen Group Order Postponed
Because of the rhododendron plants we are trying to raise for the 2006 Convention, we have decided not to attempt a Van Veen Group order this year. Anyone want to chair the plant committee?

Convention Volunteers Needed
Plans are coming together for the 2006 convention next May, but we will need people to help out. Please volunteer! We will need bus captains, people to stage the plant sale, and much more.

Preston Davis Passes
Sadly, we must report the loss of O. Preston Davis on April 29, 2005. Preston was 94, and a longtime member of our chapter. He will be missed.

Chapter Field Trips

If you could not join us on the chapter field trips this year, you missed some great fun. In May, we took an overnight trip to the Blue Ridge Mountains from Charlottesville to Roanoke. In June, we spent nearly a week repeating the successful 2002 field trip to Roan Mountain and Gregory Bald. On both trips, we were blessed with superb weather, gorgeous flowers, and wonderful camaraderie.

Blue Ridge Mountain Field Trip

On Monday, May 9, eight chapter members met at the Virginia Welcome Center on I-66 where we would begin our first field trip. The journey was to be a practice run for the post convention tour to the Blue Ridge Mountains that we have planned for next May. Our travelers at that point included Paul and Nan Barchowski, Bob and Rosa McWhorter, Richard Mohr, Doug and Anita Burke, and tour guide, Don Hyatt. The Burkes are associate members from Ontario, Canada.

Our first stop was Phran’s Azalea Trails, the lovely garden of Phil and Frances Louer in Haymarket, VA. The Louers have perhaps the largest azalea collection in the region with 8900 plants, some still in pots, but the balance in 200 small beds on five acres of wooded land. Their collection has 2790 different varieties representing 217 hybrid groups. The flowers couldn’t have been lovelier that day, nor the weather.

From there, we headed south to Charlottesville and historic Michie Tavern for lunch. Here we meet up with Jim Duffy and Gray Carter from Eastern Shore, as well as Dave and Virginia Banks who now live in Williamsburg, VA. After a “dietetic” traditional southern meal including their famous fried chicken, corn bread, and peach cobbler, we headed off to Thomas Jefferson’s Monticello to tour both the house and gardens.

The afternoon was getting late, so from there we headed directly to Roanoke for the evening to meet up with other chapter members including Max Byrkit and his wife, and associate members Bill Bedwell, Wally and Jane McKay, and Karel and Betty Bernady, and another ten members from the Middle Atlantic Chapter.

Tuesday morning, we organized carpools and headed out to see Paul James and his exquisite garden filled with choice plants of all kinds. Paul’s manicured garden is about 15 acres in size, filled with rhododendrons and azaleas were in peak bloom, but the James family estate extends to nearly 1000 acres. Paul has a huge collection of Delp and Haag hybrid rhododendrons, many of which we propagated for the 2006 Convention plant sale. The Haag hybrids truly impressive, like a tall white with a green throat called ‘Whitewater, NC’ and delicate pale lavender ‘Smoky Mountain’ with its dark purple blotch. They made stunning companions in the garden.

On the banks below Paul’s house are some of his older plantings. The lovely light yellow ‘Barbara Hardgrove’ near the greenhouse really attracted attention, but so did his wonderful collection of conifers and huge rhododendrons towering overhead like Dexter’s ‘True Treasure,’ a rich warm pink with a contrasting dark blotch.

Paul also has many of the Todd hybrids. Most only carry numbers and have not been introduced. The colors are pale yellow, pink, or white, and many are strongly fragrant since they are hybrids of ‘Dexter’s Spice’ or ‘Dexter’s Peppermint.’

Most of Paul’s Delp hybrids are located on an adjacent hill, so we followed the wide grassy paths that flank the steep slopes past many mature rhododendrons to see them next. The Delps are quite varied, and we saw beauties with tight trusses in lovely shades of pink, white, red, or purple, some with strong blotches like ‘Big O’ and ‘Spot Magic’. There were others with rich warm tones like the yellow ‘Delp’s Stardust’ or a peach blend with spots called ‘Magic Moods.’

Many of us returned to Paul’s lovely rock garden to admire it many horticultural treasures. It is filled with dwarf plants, wildflowers, ferns, dwarf conifers, and Japanese maples. Tall specimens of orange and yellow R. calendulaceum seemed to frame every view, and we admired the huge evergreen azaleas, too. Like many of us, Paul said that this May’s bloom was one of the best ever in his garden, and we felt so fortunate to be able to see the display on such a perfect day.

Paul and his wife Barbara had prepared some refreshments for us on their deck that overlooks the James estate. We could gaze out on his lovely garden to the mountain peak in the distance, all of which is part of their property.

In the afternoon, we returned to Roanoke to pick up cars, and head for home. The trip was such a great experience. We certainly want to thank Paul and Barbara James, as well as Phil and Frances Louer for sharing their gardens with us.

Rather than heading straight home, several of us decided to travel slowly north along the Blue Ridge Parkway, planning potential stops for the post convention tour. We ate a late lunch at the excellent Peaks of Otter Lodge, and after looking over the facility decided that this peaceful location would be a perfect place to spend the night on next year’s post convention tour. We have now booked all 63 rooms for the 2006 Blue Ridge Tour.

Roan Mountain / Gregory Bald

Our second chapter field trip was a to Roan Mountain and Gregory Bald. This was a repeat of the same itinerary we took in 2002, but members of the Ben Morrison Chapter of the Azalea Society of America joined us this time. The Fall 2005 issue of the ARS Journal will have an article about our prior trip.

It is always difficult to predict the bloom in the mountains, so we had set June 13-17 for this year’s adventure. Unfortunately, we had a late spring and the season was going to be late, but we still expected to see some flowers. As time drew near for departure, many of us were apprehensive since the remnants of a tropical storm from the Gulf had moved into the Southern Appalachian Mountains. The forecast was for it to linger there for some time, but we decided to take our chances.

When we arrived in Elizabethton, TN, Sunday afternoon, the winds were gusty and it was still raining. Don Hyatt decided to check the azalea bloom on Roan, and drove to Carver’s Gap to hike up 5800-foot Round Bald. The weather was awful, the worst he had experienced there. Winds were 50 miles per hour with stronger gusts, and it was hard to see the trail as dense clouds, rain, and fog whizzed by. It was even hard to breathe. The R. catawbiense and R. calendulaceum were starting, but most of the open flowers had been ripped off by the wind. There were still buds to open, though.

Some people decided not to come, we had a rather large group anyway including Bob and Rosa McWhorter, Gabrielle and Bill Scott, Karel Bernady, Dale and Carol Flowers, Jerry Hudgens and his brother Len, Vijay and Shelly Chandhok from Pennsylvania, Barbara Bullock and her boyfriend Tom, David Goodkind, Dave and Eileen Holm, Joe Miller and Adrien, a teaching assistant from Senegal who was staying with Joe for the summer. Bob King, his wife Kelly, and son Mark would join us the next day.

We decided to postpone the hike into the Roan Highlands for at least one day. Since the storm was moving north, decided to explore the southern stretch of the Blue Ridge Parkway on Monday instead. The next morning, we headed south to Asheville where we enjoyed a lovely sunny day.

We made many stops, including a hike to a waterfall at Graveyard Fields. By late afternoon we found ourselves on Wayah Bald, south of the Smokies. The view of the mountains from the observation tower was excellent. We enjoyed the fragrant R. arborescens that was opening, and R. calendulaceum was in full bloom everywhere.

By now, the tropical storm had moved into the Ohio Valley, and the forecast for Tuesday was clear skies. We returned to Elizabethton and planned for our hike along the Appalachian Trail in the Roan Highlands the next day.

We rose early and drove up to Carver’s Gap where we would begin our hike. The weather was cloudy at first but soon became spectacular, sunny and clear with great visibility. We saw the Roan Rhododendron Gardens first, and then took out for our hike along the Appalachian Trail.

As we reached Engine Gap, the flame azaleas that Don had seen on Sunday night in tight bud had begun to open and were lovely. We strolled among those for quite some time. Don shuffled between three cameras trying to photograph every leaf and flower, but eventually realized that he had dropped his glasses somewhere among the tall grasses and flame azaleas on that enormous bald.

After a vain search for Don’s glasses, we continued out to Jane Bald and Grassy Ridge for lunch. We were surprised to meet Paul James and his brother’s family on the trail. They had come to enjoy the azaleas and incredible views, too.

We missed the big R. catawbiense bloom this year. The buds had apparently been damaged by a late freeze and never opened fully anyway. Many of the rhododendrons were lovely, though.

While Don went into Johnson, TN, to get new glasses the next morning, the rest of the group headed south to Vivian Abney’s East Fork Nursery to buy native azaleas. Later in the day, some hiked to Clingman’s Dome in the Great Smoky Mountain National Park, while others relaxed along rushing streams. We reconvened in Townsend, TN, that night for the Gregory hike.

Thursday morning we rose early so we could be on our way by 6:00 AM. It is a long hike, and an early start means more time on the bald. We did stop to appreciate sunrise over Cade’s Cove before starting the four-hour ascent to the bald.

Peak bloom on Gregory was probably two weeks away but we were not disappointed. The azaleas bloom on the bald usually from June into July, so we knew we would likely see some of those famous plants in flower on this trip.

Many of the earlier blooming varieties were at perfection. We found azaleas in the full color range: white, pink, red, orange, and yellow.

Those of us who have been to Gregory before saw plants in bloom we had not seen before. Some showstoppers this year included a huge 8 to 10-foot plant with glowing flowers of yellow and golden orange. We called that one ‘Tequila Sunrise.’ We admired an exquisite pale pink and white, and a plant with double flowers! We had never seen any doubles on Gregory Bald before.

The entire trip was fantastic, and we returned home with sunburns, sore muscles, photographs, and great memories. Our chapter now has many more Roan and Gregory Bald tour guides.

Rhododendron calendulaceum: Variations in the Wild
by Donald W. Hyatt and George K. McLellan

The following is an excerpt from an article written for the 2005 Yearbook of the Rhododendron Species Foundation.

Rhododendron calendulaceum has always been one of the most highly prized of our American native azaleas. Probably the first to appreciate its beauty were the Cherokee Indians who called it the ”Sky Paint Flower” because its colorful blooms could mimic a brilliant sunset. William Bartram wrote of the species in his 1791 book Travels:

“The epithet fiery I annex to this most celebrated species of azalea, as being expressive of the appearance of its flowers which are in general the colour of the finest red lead, orange, and bright gold, as well as yellow and cream colour; these various splendid colours are not only on separate plants, but frequently all the varieties and shades are seen in separate branches on the same plants; and the clusters of blossoms cover the shrub in such incredible profusion on the hillsides, that suddenly opening into view from dark shades, we are alarmed with the apprehension of the hill being set on fire. This is certainly the most gay and brilliant flowering shrub yet known...”

R. calendulaceum is an extremely variable species, and as Bartram noted, the variation seen in the wild is quite pronounced. Such wide diversity creates a real challenge in trying to identify unusual forms since every plant is unique. By contrast, some rhododendron species are much more uniform, such as R. maximum where entire hillsides in the wild may appear as though they were planted with a single clone.

The salient feature of R. calendulaceum is surely its fiery flower color in shades of yellow, orange, or red. Orange is the most common with pure red being rare, but one should not assume that there are but three color forms of this species. The range is a continuum from light lemon yellow, through deeper butter yellow and rich gold, to innumerable shades and intensities of orange, to orange-red, brick red, and even scarlet. Some plants have flowers of apricot, peach, or salmon. Others may be blends of several colors, possibly brushed with secondary pigments like pink or red. People have reported white forms of R. calendulaceum, but not having observed these directly we cannot judge and they may be natural hybrids with other species.

In addition to the corolla color, the blotch of R. calendulaceum is a totally independent hue. Some flowers have broad areas of intense gold, orange, or yellow that can completely fill the dorsal petal and extend to adjacent petals. In some plants, the blotch may be the nearly same color as the corolla and barely noticeable. The pigment in the blotch is usually more intense than the base corolla color, noticeably opaque, and sometimes textured.

Like many native azaleas, the buds of R. calendulaceum are often a deeper color than the open flowers, but not always. We have noticed that some flame azaleas have a tendency for the flower color to deepen with age, a transition that can be very startling at times. Flowers on these plants may open clear yellow, but soon deepen to shades of orange or even deep rose red as they complete their color shift. At times, the full range of colors can be present on the same plant, or even within the same flower truss. We suspect the color shift is affected by light since flowers on a plant that open in shade seem to show less color change than those in brighter locations.

The genetics of flower-color expression in R. calendulaceum is undoubtedly complex, and surely multiple genes and multiple pigments must control the expression we see. Some of the lighter yellow and orange forms can develop an independent pink flush in the flowers. This can create lovely new shades, but can also make some other flower colors look muddy. Many plants do not show this tendency, and colors remain pure.

R. calendulaceum is known to be tetraploid, and thus has twice as many chromosomes as our other East Coast native azaleas. Research indicates R. calendulaceum is an allotetraploid, where chromosome doubling was the result of a merger of two distinct species rather than doubling of a single form. R. calendulaceum has one set of genes from the orange-red R. cumberlandense (bakeri) and another set from the rose pink R. prinophyllum (roseum). Perhaps the pink flush we see in some flame azaleas is due to R. prinophyllum, just reminding us its genes are around.

R. calendulaceum and R. cumberlandense are easily confused in the wild since they often grow in the same regions and have a similar color range. R. cumberlandense usually blooms later, after the foliage has fully expanded, and the color tends toward the orange-red to red tones rather than the orange to yellow hues that prevail with R. calendulaceum. There are many characteristics used to tell these species apart, but we have noticed a difference in the clarity of color between the two species. In general, the flower color of R. cumberlandense is usually a cleaner hue, rarely muddied by secondary pigments sometimes seen in R. calendulaceum. We concur with Skinner’s observations in his article “In Search of Native Azaleas”. When comparing flower color of R. cumberlandense to the flame azalea, he noted the former had “a color luminosity, in the filtered sunlight, that the other wholly lacks.”

Flower size in R. calendulaceum is quite variable in the wild. Although the typical corolla diameter is 2 to 2.5 inches, we have found plants with small blossoms less than an inch across, to giants with corollas exceeding 3 inches in diameter. Of course, flower size is controlled by environment, so it might not be fair to compare without growing plants under identical conditions.

Flower shape can vary significantly from plant to plant. Individual blossoms can be star-shaped with rather narrow petals, to round with broad petals, and everything in between. As the corolla widens into petals beyond the floral tube, that portion can be funnel shaped, flat, or even reflexed. Petal margins can be wavy, ruffled, flat, or frilled. There are rare strap-petal forms, too.

In several locations, we have found double flowered forms of R. calendulaceum, but the degree of doubling can vary. The stamens have become irregular petal parts, and often have anthers attached.

Plant habit is quite variable. Some plants are tall and willowy, especially those in light shade or at the boundary of a forest clearing. They can reach heights of 15 feet, possibly more. On the open balds, the largest plants we see are usually half that height. Plants growing in full sun are typically more robust, putting on 8 to 12 inches of new growth in a season, with the most vigorous growth usually originating from the base of the plant. Perhaps the reason azaleas in open locations do not reach larger sizes is that winter exposure seems to eventually kill some of those older branches. Recurrent loss of woody stems keeps them from getting as tall as plants growing in sheltered spots.

In addition, we have observed occasional plants that appear very compact to almost dwarf, some growing but an inch or two each year. Of course, we wonder if the dwarf habit would continue to be expressed if that plant were growing in a different environment. We have also seen plants that appear to be prostrate with obvious horizontal branch structure whereas others nearby are upright.

The variation in this species is amazing. We have observed innumerable color forms, variations in flower shape and size, plant habits from dwarf to robust, and widely varying blooming times.

Standing on the top of 6684-foot Mount Mitchell, the highest peak in the eastern United States, we have gazed out on the innumerable mountain ranges that extend in all directions to five different states and wondered, “What other rare forms of this spectacular species might be hiding in remote locations?” Some of those azaleas are cloaked in heavy shade now and may have to wait for decades, perhaps centuries, before the canopy opens up again so they have sufficient light to flower heavily and reveal their charm.

Copyright © Donald W. Hyatt