JARS v54n1 - Rhododendron Diversity: The Challenges of New England

Rhododendron Diversity: The Challenges of New England
Dick Brooks
Concord, Massachusetts

New Englanders have been growing rhododendrons in their gardens and public places for close to a century and a half. By 1873, Mr. H. H. Hunnewell of Wellesley, Massachusetts, had sufficient numbers of these aristocrats of the plant kingdom that he was able to stage an exhibition of his plants on Boston Common for the benefit of the public. By the end of the century rhododendrons were being planted by the hundreds and thousands all over this corner of the nation. Despite the vicissitudes of climate, many of these venerable plants are still flourishing today. But in the intervening years great progress has been made, and continues to be made, in the plants available to the gardening public: the range and variety of the types, their adaptability to different climates and soils, and their landscape value.

The Massachusetts Chapter invites you to come to Boston this spring and experience for yourself the remarkable phenomenon of New England rhododendrons. Your ARS Convention 2000 Committee has lined up a first-rate program of speakers, garden tours, truss show, plant sale, book sale and other events designed to showcase our successful breeding and cultivation of this distinguished genus. You will see that the challenges of raising rhododendrons in a less-than-ideal climate have been met and overcome, and the resulting diversity of plants growing here will astonish and delight you.

Our venue will be the Marriott Hotel in Burlington, Massachusetts, a northern suburb of Boston. Your committee has secured a most favorable room rate for this event ($99 plus tax, vs. the hotel's standard corporate rate of $279), effective from Tuesday, May 23, through Sunday, May 28. The facilities are ample for our planned activities and the location makes for easy access from major interstates. Public transportation to Boston is available two blocks from the hotel.

The Garden Tours

Convention-goers will be able to select from eight different garden tours:

Wednesday May 24:

TOUR A: Arnold Arboretum (half day). The Arboretum, founded in 1872, is the result of a unique collaboration between an educational institution and a municipality; it is at the same time a botanical garden of Harvard University and a public park of the City of Boston. Its grounds were laid out by Charles Sprague Sargent, its first director, and Frederick Law Olmsted, America's preeminent designer of public parks. It remains one of the best preserved of Olmsted's landscapes. In its one-half square mile of grounds the Arboretum displays more than 4,000 species and cultivars of trees, shrubs and vines hardy in USDA Zone 6. Most of the plantings are grouped by plant family, arranged in botanical order along the main drive, making it easy to locate particular groups and to compare plants within a group. Because of the extent of the grounds we will tour the Arboretum by bus, with frequent stops at rhododendron, azalea and their companion plant collections.

R. 'Duke of York'
R. 'Duke of York' at the Arnold Arboretum, an English hybrid introduced
about 1894 and still highly regarded by aficionados.
Photo by Dick Brooks

TOUR B: Weston Nurseries (half day). One of the largest growers in New England, Weston Nurseries, covers 650 acres in the town of Hopkinton (Zone 5). Hundreds of different types of trees, shrubs, vines and perennials are offered in their extensive catalog. But the chief interest for ARS members is in Weston's long-running breeding program for rhododendrons and azaleas. Three generations of the Mezitt family have been pursuing several goals for improving the kinds available to gardeners, not only in New England, but throughout the colder regions of the nation (see article "The Weston Hybrids" in the Fall 1999 ARS Journal).

Thursday May 25:

TOUR C: Cape Cod Gardens (full day). Tour C will include visits to Heritage Plantation and Salishan East, both in the town of Sandwich. Heritage Plantation is well known to rhododendron aficionados as the home of Charles Dexter, who from 1920 until his death in 1943 produced literally tens of thousands of new hybrid rhododendrons. Many of these were subsequently named and distributed. However, Heritage contains not only the Dexter hybrids, but also hundreds bred by Jack and Evvie Cowles while they were horticulturists on the estate from 1959 to 1967. Both the Dexter and Cowles plants are now magnificent mature specimens and should be in full spectacular bloom for our visit.

Salishan East is the garden of Marcia Duplinsky and her late husband, Joe. It is situated on four acres facing Cape Cod Bay. The climate is moderated by the sea, providing ideal conditions for raising the more tender plants, including H4 rhododendrons and even camellias. This spacious and carefully landscaped garden combines rhododendrons with a splendid array of unusual trees and shrubs collected during a number of trips through the United States, England and Scotland.

TOUR D: South Shore Gardens (full day). Participants on Tour D will view the Zone 6 gardens of three avid collectors: Barbara and Gene Gingras, Barbara and Henry Wrightington and Jane and Ian Donovan. The Gingras place is eight acres in extent, of which two acres are devoted to over a thousand rhododendrons, many of them rare Dexter, Consolini and Cowles hybrids, as well as native swamp azaleas. This wonderful rhododendron collection is over 15 years old and still expanding into the adjacent open woodland. Also featured are a stream, trout pond and pastures where Barbara raises prize sheep for show.

The Wrightingtons' garden covers several acres of land originally covered with such a thick canopy that nothing survived in the dense shade. Gradually they began clearing, and over the past twenty years have developed a woodland garden featuring rhododendrons. Ardent plant collectors, they have assembled many named and unnamed Dexter hybrids, as well as hybrids of John Wister, Orlando Pride, David Leach and Weldon Delp. Magnolias, dogwoods and many native wildflowers help to create a most attractive landscape.

Jane and Ian Donovan's garden in Pembroke is the youngest of the three, approaching seven years since the standard builder's landscape was bulldozed and new beds constructed. Look for tree peonies, magnolias, fringe trees, deciduous azaleas and rhododendrons in abundance. Several other minor flowering trees and shrubs dot the property, along with a garden of dwarf lepidotes.

TOUR E: Western Gardens (full day). The tour will visit six private gardens located in the rather rural western suburbs of Boston. Each garden is a unique, passionate, personal collection of species and hybrid rhododendrons, planted under the white pines and oaks characteristic of this part of the state. George Hibben's Zone 6 garden in Lincoln is set in a wooded glade adjacent to a meadow, orchard and an 18-acre pond. There are over 150 rhododendrons, the oldest planted eight to ten years ago. They include species, Dexters, the best of the "proven performers" for New England, and many promising hybrids raised from crosses made by Massachusetts Chapter members. Propagation and growing-on beds are adjacent to the garden, lnterplanted with the rhododendrons are many companion trees and shrubs, including Acer griseum , Callicarpa japonica , Cercis canadensis , Fothergilla major , Hydrangea quercifoiia , Stewartía obassia and Styrax japonicus .

R. 'Dexter's Giant Red' x R. yakushimanum,
Whitney dwarf
R. 'Dexter's Giant Red' x R. yakushimanum , Whitney dwarf, a new hybrid
in the Hibben garden, raised from seed by George Hibben.
Photo by Dick Brooks

Susan Clark grows rhododendrons on a 2-acre Zone 5 site sloping down to the Sudbury River. There are over 150 rhododendrons, including almost forty species and forty azaleas. They are placed throughout the landscape with a wide variety of other shrubs and ornamental trees, about forty different hostas, and a great variety of perennials and wildflowers. Large white pines and red and white oaks provide high shade and frame the views of the beautiful river. The garden reflects the constant tension between greedy plant acquisition and aesthetic principles of garden design.

In the same neighborhood as Susan's, Bill Sweeney's garden is a one and one-half acre site heavily wooded with oaks, maples, birches and pines, at the end of a glacial moraine and above a "kettle-hole" bog. The soil is a mixture of yellow clay and broken granite, making the digging of a planting hole a real challenge. Over the last twenty years the woods have been thinned to permit the planting of about 100 rhododendrons (mainly hardy hybrids and some species), companion plants and under-story trees in an informal array. Plants native to the site include Chamaedaphne calyculata (leatherleaf), Rhododendron canadense and R. viscosum in the bog area.

Next door to Bill Sweeney's is Dick Brooks's eclectic collection of over 800 different rhododendron species and hybrids. Dick has been growing these plants and evaluating their performance at his Zone 5 site, some for as long as forty years. The rhododendrons range from old standbys like 'President Lincoln' to newer Hachmann and Leach hybrids, and species grown from seed (e.g., R. calendulaceum ) to species from the Rhododendron Species Foundation (e.g., R. wasonii ). They occupy the understory of a mature stand of eastern white pines (some approaching the century-and-a-half mark) and are accompanied by a variety of native and exotic wildflowers.

The Brooks garden, Concord,
Rhododendron border in the Brooks garden,
Concord, Massachusetts.
Photo by Dick Brooks

Farther west in the town of Harvard (Zone 5) are two woodland gardens designed by teacher, author and landscape professional Neil Jorgensen. The extensive Chandler garden is replete with fetching vistas of grassy swards, rocky outcrops, ponds, many rhododendrons and an array of groundcovers and perennials. Nearby is Neil's own garden, partly on fairly level ground and partly on a steep hillside, featuring hundreds of rhododendrons and azaleas at varying stages of maturity, as well as sheets of perennials such as Primula japonica and Phlox stolonifera .

TOUR F: Mount Auburn Cemetery (half day): Mount Auburn was established in 1831 by the then newly organized Massachusetts Horticultural Society. As the first garden cemetery in America, it soon became the largest, best planned and best planted public garden in the country. It was the inspiration that led to the development of public parks and gardens throughout the nation. Mount Auburn's ancient plantings, continually renewed with fresh seasonal plants, have attracted visitors from all over the world. We will visit the most historic parts of the garden in a guided walking tour. Those who wish may climb the Mount itself (an easy climb) for a spectacular view of the Boston skyline. A limited number of places will be available in a small van for those unable to walk the tour.

Saturday May 27:

TOUR I: Southern gardens (full day). This tour will visit three unique and distinctive gardens in the benign coastal climate of southeastern Massachusetts and Rhode Island. At the Kinney Azalea Garden, 800 cultivars of azaleas flourish in a unique naturalized setting. This semi-public garden/nursery was founded in 1956 by Dr. Lorenzo Kinney and features mature plants in their stately natural forms. Gables and Glenn Dales share the romantic vistas with rhododendrons, mountain laurel and leucothoe. Giant umbrella pines shelter Exbury, Satsuki and original azalea cultivars, ablaze with color from mid-April to early summer.

The Huie garden of about three acres is on the border between USDA Zones 6b and 7a. Originally the land was a cow pasture with a growth of young native shrubs and trees. Powell Huie cleared the land and built a house in the mid 1960s and began a planting program which over the years included rhododendrons and other ornamentals. At present in the collection are over 500 rhododendron hybrids, including many Dexters. There are also more than 125 different species (the majority less than five years old) which are still being tested for hardiness and adaptability to the area. In the lath house visitors will see an additional ninety species plants that will be moved into the garden after two or more years, if they survive the local climate.

Quite different in character from the woodland gardens described above is the seaside garden of Berthe Atwater. A large property of some fifteen acres, it contains several large shrub borders featuring rhododendrons and azaleas, rock gardens containing dwarf evergreens and rhododendrons, and numerous small trees and shrubs which have been meticulously pruned and espaliered into graceful forms. The hand of a master gardener is evident in each lovingly tended plant and each exquisite detail.

Atwater garden, Sakonnet, Rhode Island
A view in the Atwater garden, Sakonnet, Rhode Island.
Photo by Dick Brooks

TOUR J: Northern Gardens (full day). The destination for this tour is the 6-acre property of Joe Parks in southern New Hampshire (Zone 5A), actually a series of lovely gardens in a variety of settings. There are over a thousand rhododendrons and azaleas here, many of which are Joe's own hardy hybrids; some of these have been or are about to be registered. Two rock gardens and a stunning array of attractive companion plants should also be in bloom for our visit.

En route to or returning from New Hampshire we will stop at four smaller gardens, each a unique expression of its owner's interests. The 100-year-old Stevens-Coolidge place in North Andover, now a property of the Trustees of Reservations, includes a beautiful formal perennial garden and a walled rose garden. Adjacent to the Stevens-Coolidge place is the much younger garden of Bob and Dana Fox. Only five years old, this garden already is home to 190 rhododendrons and seventy heathers and hostas.

Leslie and Norman Frost's garden, thirty years in the making, is a shaded garden with many mature rhododendrons and companion plants. Finally, Bob and Joan Means' garden in Georgetown is a true plant collector's paradise; rock gardens and woodlands abound in rare and unusual plants of every kind.

Open Gardens

A number of members of the Massachusetts Chapter and the Cape Cod Chapter have agreed to open their gardens for visits by attendees before and after the actual Convention. This may lend itself to one or two days of touring. If you would like to receive a listing and information on these gardens, check the appropriate box on the registration form.

Other Tours

For the benefit of Convention attendees whose interests encompass subjects other than gardens, your Committee has scheduled three other tours.

Friday May 26:

TOUR G: Historic Lexington and Concord (full day). Our Historian/Guide will take us into the town of Lexington, to re-live the beginning of the American Revolution on April 19,1775. After stopping at Lexington Green, the Minute Man statue, the Old Burying Ground and historic houses, we will travel the Old Battle Road to Concord. On our way to the North Bridge and Minute Man National Park headquarters we pass Orchard House (home of the Alcott family), Emerson House, Wright Tavern and the Old Manse. After lunch at the park we will have time for their video presentation and exhibits. Next we return to Lexington to visit Buckman Tavern; we finish the day at the Museum of Our National Heritage, to see a permanent exhibit on the American Revolution and visit the gift shop.

TOUR H: Charles River Dinner Cruise (evening). Attendees will have the pleasure of a ride on historic Charles River and Boston Harbor, followed by dinner on board. We will have a tour conductor who will point out the several historic sites along the route. Each of the distinctive riverboats is appointed with a teakwood bar and moldings, handsome carpets and antique brass fixtures. The tour along the river offers spectacular views of the Boston and Cambridge skylines as we go through the locks and out to the harbor.

Saturday May 27:

TOUR K: Best of Boston (full day). This tour will take us first to the Charlestown Naval Yard to experience a great national treasure, the USS Constitution ("Old Ironsides"). From Charlestown we travel to downtown Boston, viewing the historical sites along the "Freedom Trail," as well as a look at the North End, Back Bay and Cambridge. Lunch will be on Boston Common, our country's oldest park, dating back to the founding of the city in 1630. The Mueum of Fine Arts is next. Over 125 years old, this world class museum has outstanding collections of the art and culture of civilizations worldwide. We may enjoy the museum's Japanese garden and its fine gift shop before returning to our hotel.

In addition to the scheduled tours, attendees may wish to explore Boston's many shopping attractions. Shop on your own by taking Boston's transit system, available from our hotel. The Back Bay provides a rich mix of graceful Victorian and brownstone residences, eateries and chic shopping. Newbury Street has art galleries, cafe/restaurants, boutiques and unique stores. The high-style stores of the Prudential Center and Copley Place complexes are connected by overhead walkways in case of rain. See the city from the top of the Hancock or Prudential Tower. Commonwealth Avenue's tree-lined promenade ends at the famous Public Gardens, home of the famous Swan Boats.

The Speakers

The lecture program for ARS 2000 builds on the diversity of climate that is found in New England for garden cultivation of the Ericaceae. Underlying themes for this year's program include hybrid hardiness, plant conservation in the wild, where we've been with our garden hybrids and, most importantly, what the future holds for our favorite genus.

The theme will be set by Walter Ostrom's keynote address on Wednesday evening. Walter is famous for his extensive garden on the coast of Nova Scotia, and is not only a knowledgeable plantsman but a most entertaining speaker. After a busy day of tours on Thursday, an evening talk by Wayne Mezitt, president of Weston Nurseries, will summarize the nursery's important role in developing hardy lepidotes for the trade. Even more exciting will be Wayne's review of the nursery's new direction to extend the blooming season into summer by introducing fragrant, colorful and mildew-resistant deciduous azaleas. These improved plants must meet the tests of being hardy, decorative in the landscape, and easy to grow by the gardening public.

Vital to success with our favorite plants in New England is the concept of hardiness. While hardiness may not be an overriding concern in the warmer parts of our growing area, it is central to the selection of plants for most gardens. On Friday morning we'll explore this issue through a lecture by Dr. Jon Valigorsky, who gardens in USDA Zone 4 in western Massachusetts at the New York state border. Next will be a panel discussion, moderated by Richard Bir, to address ideas and issues about rhododendron and azalea hardiness.

Following the panel discussion, the program will feature a series of short talks that will highlight many facets of rhododendron and azalea development and gardening. There will be talks on pruning, control of insect and disease problems, the new little-leaf mountain laurels, conservation of our eastern native azaleas, propagation and introduction of native plants into the garden, and the late Dr. Gustav Mehlquist's work in developing better plants for us. Most talks will be repeated once during the day.

Among the featured speakers will be Robert Childs, an Extension Specialist at the University of Massachusetts, an interesting, informative speaker whose special interests include Integrated Pest Management. Richard Jaynes is nationally known for his work with the genus Kalmia , and as the author of the definitive book on the subject. Dr. Sandra McDonald has long been involved with ARS activities, on the Editorial Committee, on the Research Committee, and as author of numerous articles in the Journal (for example, see "Magic on the Mountain", in the Spring 1996 issue, for an account of the native azaleas on Gregory Bald). Richard Bir is with the North Carolina State University Extension Service, and is an expert on the flora of the southeastern U.S. Laura Chappell is a past president of Connecticut Chapter ARS and the owner of Chappell Nursery in Lebanon, Connecticut, where she has grown and offered many of Dr. Mehlquist's introductions. M. S. Viraraghavan of Kodaikanal, India, is retired from government service as Director of Agriculture and Horticulture as well as Secretary in the Food and Agriculture Department; his collection of rhododendrons includes many vireyas and hybrids of R. arboreum .

On Friday evening, as an alternative to the optional Charles River Dinner Cruise, there will be a talk by Jonathan Leonard summarizing the 20th century work with elepidote rhododendrons in Massachusetts by Charles Dexter, Tony Consolini and Jack Cowles. Jonathan, who has studied and worked with these plants for many years, will suggest where we should be going with this wonderful gene pool at the beginning of the 21st century.

After a full day of tours on Saturday, Kenneth Cox, noted plant explorer and nurseryman, will entertain us after the banquet with a talk entitled "Nuclear Bombs and the Sacred Valley of Tsari."

Sunday morning will feature a potpourri of programs for several audiences. Keith Adams, a New Zealand native, will speak on vireya conservation in the wild. Brian Maynard of the University of Rhode Island will speak on innovative propagation methods and deer control. ARS Executive Director Dee Daneri will lead a Society Issues Forum. And longtime Massachusetts Chapter member and hybridizer Tony Knights will moderate the perennially popular Breeders' Roundtable.

Plant Sale

The Convention plant sale will emphasize New England hybrids and other choice plants. We have a number of suppliers currently growing plants, and eager to participate "under the big top" (the sale will take place in a large tent just outside the entrance to the hotel).

R. 'New Century'
R. 'New Century', a new hybrid by Weston Nurseries, Hopkinton,
Massachusetts, to be featured in the Convention plant sale.
Photo by Weston Nurseries

Weston Nurseries, noted for hybridizing New England hardy rhododendrons and azaleas, will feature three new introductions. 'New Century' is a compact growing elepidote with glossy dark green foliage and yellow flowers (see description in the Spring 1999 Journal). Wayne Mezitt says that 'Landmark' is the best near-red lepidote that he has yet seen; the flowers are a brilliant dark pink that appears red from a distance (see description in the Fall 1996 Journal). 'Millennium' is a deciduous azalea with viscosum/prunifolium ancestry; it blooms in July with fragrant red flowers. The bluish-green foliage with silvery undersides is mildew-resistant (see description in the Spring 1999 Journal).

R. 'Landmark' and R. 'Blue Baron'
R. 'Landmark' and R. 'Blue Baron', new hybrids by Weston Nurseries,
Hopkinton, Massachusetts. 'Landmark' will be featured in the Convention plant sale.
Photo by Weston Nurseries

The Massachusetts Chapter's Plants for Members program (PFM) raises a thousand or more plants every year from cuttings taken from the choicest plants in members' gardens. This year these plants, many of them now husky two-year-olds, will be available to Convention attendees and will provide us with a tremendous selection of interesting kinds.

In addition to PFM, several Massachusetts Chapter members are raising plants for sale at the Convention. For example, Dick Brooks's hybrid 'Crimson Constellation' will be introduced (see description in the Fall 1994 Journal). Some of the better Ghent azaleas will be offered, including 'Narcissiflora', bred before 1873 and still one of the best and most sought-after deciduous azaleas.

R. 'Crimson Constellation'
R. 'Crimson Constellation', a hybrid by Dick Brooks of Concord, Massachusetts.
It will be introduced at the Convention plant sale.
Photo by Dick Brooks

From Van Veen Nursery comes 'Sonny's Love', a lepidote with double to triple hose-in-hose flowers, grown from seed gathered in Sitka, Alaska, and rated hardy to -25°F. Also from Van Veen are a number of "oldies but goodies," including 'Boddaertianum', 'Broughtonii', 'Clementine Lemaire', 'Madame Cochet' and 'Van's Old Port'.

Dick Jaynes of Broken Arrow Nursery in Connecticut will have selections of his mountain laurels for sale. These will include 'Madeline', the first double-flowered (hose-in-hose) mountain laurel, and 'Meteor', a new introduction with flowers of light pink marked with pale burgundy and deeply cut lobes, indicative of its 'Shooting Star' parentage. There will also be a dwarf Japanese winterberry, Ilex serrata 'Koshobai'.

Kalmia latifolia 'Madeline'
Kalmia latifolia 'Madeline', a new cultivar with
double flowers, discovered in a New Zealand garden,
will be featured in the Convention plant sale.
Photo by M. J. Chappell

Blanchette Gardens in Carlisle, Massachusetts, already famous locally, is becoming well-known outside of New England as a prime source for choice, new and rare varieties of companion plants. Leo Blanchette has selected several of these to offer at the Convention; they will include at least ten different Polygonatum (Solomon's seal), including P. hirtum , P. odoratum 'Grace Barker', P. curvistylum , P. oppositifolium , and P. zanianscianense . There will also be several rare trilliums and some newer astilbe varieties.

Finally, Chappell Nurseries in Lebanon, Connecticut, is supplying several of the newer Mehlquist rhododendron introductions, including 'April Mist', 'Connecticut Yankee', 'Ingrid Mehlquist' and 'Scarlet Romance'.

Silent Auction

There will be a tempting silent auction of rare plants, valuable gardening books and other items donated by generous individuals.

Other Sales

A wide selection of books will be offered to Convention attendees, as well as other items such as T-shirts with the distinctive Massachusetts Chapter logo.

Truss Show

Convention attendees are encouraged to bring cut blossoms of their choicest rhododendrons and azaleas to enter in this judged show. A hotel refrigerator will be available to hold your entries in good condition until show setup time. If you plan to bring entries, check the box on the registration form to receive the show rules, classes and trophy details.

Photo Contest

Photographers are invited to bring samples of their work to exhibit. If you plan to participate, check the box on the registration form to receive the rules and categories.

Public Workshop

As part of its educational outreach commitment, the Massachusetts Chapter is planning a day-long workshop on Saturday, May 27, while Convention attendees are away on tour. This will cover the basics of successful rhododendron culture, and will be directed toward non-ARS members. It is hoped that by this introduction local gardeners will be encouraged to join and enjoy the benefits of ARS membership.


We think you will agree that the program we've planned is outstanding and we look forward to welcoming old friends and new to New England in May!