In January, 1968, while I was Director of the Strybing Arboretum in San Francisco,
R. leucogigas flowered for the first time in the Western Hemisphere and
a detailed account was published in the October Issue of the
A.R.S. Quarterly Vol. 23, No. 4. Because of the fragrance, texture, form and size
of the flowers, this new species, discovered by Dr. Sleumer in W. New Guinea,
has a tremendous potential for the hybridist. Unfortunately, it lacks the necessary
hardiness required for less equable climates than its tropical homeland. Nevertheless,
attempts were made to combine the fine qualities of this new arrival with hardier species,
but to no avail. If any reader knows of a successful cross between any of the Malesian
species and their hardier relatives, I would appreciate hearing from them. According
to records of the Royal Horticultural Society, there were crosses made between members
of the Fortunei Series and certain "Javanicum Hybrids". In 1885, R. 'Pearl' received
an F.C.C. It was a cross between R. 'Princess Royal' (jasmanicum x javanicum)
and R. griffithianum. About the same period, Mr. Noble introduced
R. 'Lord Wolseley' which was a cross between R. 'Duchess of Teck' (a
griffithianum hybrid) and R. javanicum. To my knowledge, neither is
in cultivation today.
As I had hoped, the progeny from the cross ('Sir Geo. Holford' x R. leucogigas)
made at Strybing has the shorter inter-nodal growth and more compact habit of
'Sir Geo. Holford', the seed parent, plus the heady fragrance of R. leucogigas,
the pollen parent. In a recent letter from Dr. John Evans, he enclosed the
color transparency illustrated on the color page and describes it as follows
"this is the best truss of your cross of 'Sir Geo. Holford' x leucogigas.
There are three of them now planted out in the new rhododendron area just past
the succulent garden (in Strybing Arboretum, S.F.). They are growing well and
we expect that they will become large vigorous plants... The flowers are fragrant,
the truss is 1 1 inches across with an excess of 24 corollas". He also stated
that out of eight plants in the Arboretum, two survived during the December, 1973
freeze when temperatures dropped to 23 degrees F. Obviously, Malesians are not
for general garden use along the Pacific slope. However, consider the possibilities
for the florist industry. Many of them are delightfully fragrant, i.e.
leucogigas, konori, zoelleri, and many have brilliant color
combinations unknown in their hardier relatives. In others, the flowers have
great resistance to hot weather. For example, A. W. Headlam, writing from Australia,
stated that R. laetum flowered in January when temperatures ranged from
94 to 110 degrees F. Yet when the flowers finally dropped in mid February, the
color (a rich daffodil yellow) had intensified rather than faded. In habit,
the Malesians range from low pendulous plants, as in R. rarum, to small
leaved erect heath-like plants, as in R. womersleyi, and handsome foliage plants as in
leucogigas and konori. In addition, Malesians are native at latitudes
between 15 degrees north and 15 degrees south where daylight is almost equal to dark
and where there is relatively little variation in seasonal temperatures. Consequently,
mature plants tend to flower, put on new growth, and flower again the same year.
Peter Sullivan, at Strybing Arboretum, is creating some very exciting hybrids
as are some of the growers in Australia. Michael Black in England has suggested that
R. kawakamii, a member of the Vireya Section and native to Formosa at 7000 ft.
altitude, may be compatible with the Malesians and, if a successful cross were made,
would provide a measure of hardiness to the exotic species from Malesia. Species
belonging to the Stamineum and Irroratum Series occur in Malesia and might provide
the bridge. Disregarding the possibility of combining hardiness with the beauty
of the Malesians, is it not possible that the hybridist would re-arrange the many
desirable qualities of these Malesians and produce a low, compact highly colored,
fragrant race of Rhododendrons suitable for pot culture and which would flower
more than once a year? Perhaps in time they would replace the ubiquitous Chrysanthemum!
