JARS v38n3 - Rescuing the Ghent and Rustica Flore Pleno Azaleas

Rescuing the Ghent and Rustica Flore Pleno Azaleas
Archie Skinner
Reprinted from Journal of The Royal Horticultural Society, November 1983

Archie Skinner, Head Gardener for the National Trust at Sheffield Park in Sussex, writes about rescuing and preserving this old group of plants for which he holds the National Collection.

A writer in a bulletin of the Rhododendron and Camellia group in October 1981, posed the question, "Are we too late to save the Ghents?" - a charming and once popular group of azaleas. Regretfully, we are too late to save but a mere handful. In the nineteenth century there were 200 cultivars. Now, only about two or three dozen remain, so they make a good illustration of the need for the setting up of the conservation body, with special reference to gardens and garden plants - The National Council for the Conservation of Plants and Gardens (NCCPG).
The Ghent azaleas are distinguished by their fragrant, long tubed, honeysuckle-like flowers and good autumn colour. In habit they are more bushy than the mollis azaleas, and their flowering period starts late, at the end of May. This is an advantage as they avoid any late frosts.
The decline of these, the oldest azalea hybrids, was hastened by the arrival of the Knaphill and Exbury hybrids, developed by Anthony Waterer and Lionel de Rothschild, which made a great impact in the 1930s and of course are still popular today. Upon reflection, it is surprising that the dedicated lady gardeners and plants-women, with their good taste, did not take these beautiful Ghent azaleas into their care, to conserve and popularize them, as they have done for so many other, good, but neglected garden plants, e.g. old roses and many cottage garden treasurers. One would have thought, that the elegance, combined with the perfume of the Ghent azaleas would have been particularly pleasing to the ladies.

The history of the Ghents really began with the introduction of the first azalea in 1734 from North America. This was the swamp honeysuckle Rhododendron viscosum , a sweetly scented, white, late flowering native of Virginia. At about the same time R. periclymenoides (nudiflorum) , the pinxter bloom arrived. Both species had been sent by John Bartram, to Peter Collinson, a linen draper in London. (The friendship between these two men was instrumental in introducing quite a number of new plants to our gardens e.g. river birch, Betula nigra , red oak, Quercus rubra and Lilium superbum ). Rhododendron periclymenoides is pale pink to violet in colour, with occasional double flowers being produced. It is found from South Carolina to Tennessee, and also in West Virginia and New England.
The next species from North America, which was to play a part in the production of Ghents, was the brilliantly coloured sky paint flower of the Cherokees, R. calendulaceum , introduced to Europe by the French botanist, Andre Michaux in 1806. This, the brightest of all azaleas may be seen colouring the hillsides of Carolina with its orange flowers.
One of the finest of all rhododendron species first reached this country about 1792, with a further introduction in 1796; this was Rhododendron luteum , the lovely yellow azalea with a delightful perfume and superb autumn colouring, easy and hardy, with a very strong constitution. This species came, not from North America, but from the Caucasus, sent to London by a German, Peter Simon Pallas.

These were the main species used by the hybridizer to produce what were to become known as the Ghent azaleas. The most successful of the early hybridizers was P. Mortier, a baker of Ghent, and two of his hybrids are still obtainable today, 'Ignea Nova' and 'Coccinea Speciosa'. Most of his work was carried out in the 1820s to 1830s. Thomas Rivers, the well known nurseryman of Sawbridgeworth, saw Mortier's hybrids in 1835 and gave an enthusiastic report of them to the Royal Horticultural Society. Mortier later sold his stock to Louis Verschaffelt who continued the work. Similar crosses were made by J.R. Gowen on the Earl of Carnarvon's estate at Highclere.
Among the Ghent azaleas were some which had double flowers, the result of the stamens being converted into petals. These doubles, when crossed with the Mollis azaleas in the late 1800s produced the Rustica Flore Pleno group which has close affinity to the Ghents, and like them, are in need of conservation before it is too late.
At Sheffield Park Garden, we have been interested in saving the Ghents for a number of years, realizing the value of this group, having already in the garden, two large plants, one of 'Bouquet de Flore' and a six foot high (1.8 m) specimen of 'Pucella' ('Fanny') - the beauty and form of which encouraged us to acquire and grow the few which are still available.

The site we chose for planting is a sloping bank facing south east, and sheltered by Scots pine and oak (although shelter is not a prerequisite as the Ghents are hardy) with an acid soil (pH5.5).
The area was completely covered in Gaultheria shallon , which looked a formidable task to clear, but proved not so difficult once started. The main concern was to make sure the roots were completely eradicated as they are liable to regenerate.
In our planting scheme we have endeavoured to arrange the colours so that the brightest and heaviest colours are at the bottom of the bank, and nearest to the viewer, with the softer, paler colours towards the top of the bank. There will be a need, at a later date, to open up the comparatively close planting, but at the present time it does provide shade and a better effect with massed colours.
There is no room here for descriptions of all the Ghents we have planted, so I will restrict my selection to a few which are still available, some familiar, but others which are not so well known, but obtainable from a few specialist nurseries.
The best known and most easily obtainable of the Ghents is 'Coccinea Speciosa'. Its flowers are bright orange with a yellow flare, the long protruding stamens are an attractive feature. It also has good autumn colour. The award of the AGM in 1968 is ample proof of its value in late May and early June.
'Bouquet de Flore' is a personal favourite, and, like the former, one of the oldest Ghent hybrids. It will eventually make a large graceful shrub, six foot high (1.8m) and as much across, bearing a wealth of honeysuckle-like flowers in early June, of a soft pink with a yellow stripe.

A double Ghent, worth growing for its rich autumn colour alone, is 'Raphael de Smet.' Its summer display of white double flowers, tipped pink, is an added bonus, which together make it a shrub worthy of the AM it received as long ago as 1893.
Another double Ghent which has received high acclaim is 'Narcissiflora' with well formed sweetly scented, silvery yellow flowers, and bronze autumn colouring.

A shrub which will reach ample proportions, eventually seven feet high and wide (2.1 x 2.1 m) is 'Pucella' with rose magenta flowers at the end of May, but a colour not easily placed; so it may be planted as a specimen on the lawn to advantage.
In the Rustica Flore Pleno group, there is a particularly charming cultivar 'Aida' with rose pink, scented flowers, enhanced by fresh green foliage which emerges at the same time.
'Norma' is bright deep pink from red buds, its double flowers forming a nice round truss. A cultivar, once well known, but now alas, not often seen is 'Gloria Mundi' which has particularly good autumn colour. Its flowers are bright orange with a yellow flare, and like 'Coccinea Speciosa' shows the influence of Rhododendron calendulaceum in its breeding.
This brief description of a few of our collection, will, I hope stimulate interest in this charming group of azaleas. Apart from the few listed in specialist nursery catalogues, I feel there are still a number to be rediscovered in the older gardens, perhaps even labeled, but overgrown, where the owners do not realize the rarity of their plants. The acquisition of these old cultivars does become more difficult, as smaller numbers remain to be found. The help of friends is essential to "spread the word" and we are grateful to them.

Ghent azaleas in the National Collection
The following Ghent azaleas are now in the collection at Sheffield Park: 'Pallas', 'Sang de Gentbrugge', 'Milton', 'Bouquet de Flore', 'Prince Henri de Pays-Bas', 'Aida', 'Coccinea Speciosa', 'Coccinea Major', 'Corneille', 'Emile', 'Pucella' ('Fanny'), 'Versicolor', 'Narcissiflora', 'Nancy Waterer', 'Altaclarensis', 'Raphael de Smet', 'Ignea Nova', 'Freya', 'Unique', 'Phoeas', 'Daviesii', 'Gloria Mundi', 'Norma', 'Decus Hortorum', 'Grandeur Triomphante', 'Josephine Klinger', 'Homebush', 'Charlemagne', 'Sully'.