QBARS - v11n4 Stepping Stones in Rhododendron History

Stepping Stones in Rhododendron History
By F. W. Schumacher, Sandwich, Mass.

Achievement in plan breeding rarely comes during the life time of a man who had his mind set on certain accomplishments.
Superior results in past history often have been the consequence of breeding work as continued for several generations in the same family as it had been clone in China, especially, and Japan with Azaleas, Camellias and Tree Peonies.
These notes, sketchy as they are, concern recent history.
When Charles O. Dexter in Sandwich started his breeding work within the genus of Rhododendron he was already an elderly man. Well he must have realized the odds against him. He, undoubtedly, was aware of the advantages of making use of breeding work done by others before him. How he proceeded along his way I will try to relate here:
I never met Mr. Dexter in person, what I know about his work was related to me in my frequent contacts with Anthony Consolini. Dexter, in 1922 hired him as a garden helper. He became Dexter's right hand man and confidant and after his death in 1913 had been in charge of disposing of part of his collection.
Consolini, himself a rhododendron breeder in his own right, must have been born with the proverbial green thumb and certainly is endowed with a remarkable gift of memory for past events.
Dexter's work started in 1925 or 1926 by acquiring rhododendron fortunei plants from the nearby Farquhar Nursery in Osterville. Fifteen plants were purchased the first year, about thirty more the following. It is possible to trace the origin of these plants to the Holm Lea estate of the late Professor Charles Sprague Sargent in Brookline, Massachusetts.
Having either been imported from England or grown from English seed there were two Rhododendron fortunei specimens growing in the garden. The plants had been there for many years but never had flowered as the flower buds invariably succumbed to the rigors of winter.
Before going on a vacation Professor Sargent is said to have instructed his superintendent, Charles Sander, to destroy these apparently useless plants. Sanders realizing that he had something good on his hands set out to circumvent this order.
A large barrel was cut in two into which the two plants were transferred. A dugout was prepared in a banking covered with sash and the plants moved in with the approach of winter. The following spring there came the reward of blooming, with Professor Sargent's expression of much pleasure at the result. Seed was harvested and seedlings were grown. Some of these and seed were given to the Farquhars. In the milder climate of their Cape Cod nursery the plants prospered and wintered well.
The original two fortunei plants, after the death of Professor Sargent, are said to have become the property of the Dupont Gardens in Delaware where they most probably still exist.
When after Professor Sargent's death in 1921, his large plant collection had to be sold, Dexter acquired a number of his more tender rhododendron species and hybrid plants growing in tubs. Among them was a tall, leggy plant of the hybrid 'Britannia', which Dexter used with great success in crosses with his fortunei forms. The choicest plant, of Dexter's making, those deep pink and rose fortunei hybrids are the result of these crosses.
The 'Britannia' plant figured in a cross-breeding contest between Dexter and Consolini, with a flower each between them each choose his own pollen parent for the cross, Dexter using a rather tender partner, Consolini (Toni as he is affectionately known to his friends) a hardy red hybrid from his own garden. The resulting seedlings were planted side by side for comparison. It is said that Dexter was the loser, his plants not proving hardy enough to survive winters.
Plants of Rhododendron decorum and Rhododendron discolor in species and several hybrids, all in tubs, also were obtained from the Sargent estate. All were transferred to the open ground and did well in Sandwich.
Populations of seedlings were grown from these plants. Seedlings of alleged decorum and discolor hybrids to the greatest extent turned out to be very similar in habit and flower to the respective parent species. Dexter especially favored and grew numerous seedlings from Sargent's Rhododendron decorum x 'Mrs. C. S. Sargent'. The resulting progeny being remarkable for their vigorous habit and large bright green foliage but lacking the hardiness of the fortunei crosses. Plants are said to have suffered severely in cold winters.
From seed he received from one of the English collectors Dexter raised a population of Rhododendron haematodes which he used on plants of fortunei and discolor extraction. Plants turned out to be tender, however, as regards to sun scorch in summer and winter temperatures. Not much of this material survived. Whether or not it has any value for further development remains to be seen.
After Dexter's death a large portion of his land apart from the main holding was sold. On this property, until fairly recently, could be found, with remnants still existing, some of Dexter's original nursery plots in open field plantings. There, blocks of rhododendrons, Ghent and obtusa forms of azaleas had survived without care. These plots on rather poor, sandy loam are said to have been prepared thoroughly with a clover crop plowed under and with dressing of sheep manure before planting.
After the planting Dexter expressed regret that he had chosen an open site instead of a woodland location. Little did he realize that these plantings ultimately would demonstrate the ironclad hardiness of much of the material used and the scope of variation achievable in plant breeding. Rhododendron fortunei usually represents a stout, eventually tree like plant. Here in one of the plots could be seen many specimens of apparent fortunei extraction which, apart from others, had remained dwarfish in stature with compact, spreading habit as if they had been kept sheared. Some of these with a bronze cast to their foliage, resembling Dexter's fortunei selection No. 9 which he had used in crosses with 'Britannia'. This dwarf material, I believe, should be considered of value as stepping stones for further development and breeding for a dwarf race of plants.
Notwithstanding the rather short period of his life, from about 1926 to 1943 which Dexter devoted to his breeding work, outstanding results and example to others have been his permanent achievement.
Consolini's breeding work along similar lines produced another race of hardy fortunei hybrids of moderate habit from seed imported from England. His haematodes crosses also go back to his own species seedlings which he used on his fortunei plants.
I hope that these notes may cause others who may have knowledge of Dexter's pioneer work to come forth and tell their story