36 
species of the European Alps crossed with one of the forms of the Amer¬ 
ican R. minus are excellent dwarf garden plants here. In this country 
the breeding of Rhododendrons for American gardens has never been 
systematically undertaken with full knowledge of the species available 
for the purpose. The field is an inviting one, for these plants and other 
hardy broad=leaved evergreens are greatly needed in American gardens. 
Of the early-flowering Rhododendrons those which have proved most 
satisfactory in the Arboretum are varieties of hybrids of R. caucasi- 
cum, and the Appalachian R. carolinianum. The best of the Caucasi- 
cums are the varieties called “Boule de Neige, ” “Mont Blanc” and 
“Coriaceum. ” The first is a round-topped plant rarely three feet high 
and occasionally six feet in diameter with handsome foliage and snow- 
white flowers faintly tinged with pink in the bud, in compact clusters. 
“Mont Blanc” is a taller and narrower plant with flowers rose-color 
when the buds open but soon becoming white. “Coriaceum” is also a 
more upright growing plant than “Boule de Neige” and in the rusty 
brown under surface of the leaves and in the flowers deeply tinged with 
yellow it resembles the wild plants of R. caucasicum which grow on the 
mountain slopes of the Caucasus. Two specimens of “Coriaceum” have 
been growing in the Arboretum for many years and are among the most 
satisfactory plants in the collection. Rhododendron Smirnowii flowers 
only a little later than R. carolinianum and the Caucasian hybrids. It is 
a plant with which Americans interested in the cultivation of Rhododen¬ 
drons would do well to become acquainted, for it is not only a beautiful 
plant but may prove exceedingly valuable in the production of a new 
race of hybrid Rhododendrons better suited for this climate than any 
which we now have. It is a large shrub with pale gray-green leaves 
coated below with a thick mat of pale felt, and large pink or rose-pink 
flowers in medium-sized clusters. The leaves are not as handsome as 
those of R. catawbiense and its hybrids, and when the plants are fully 
exposed to the sun the leaves sometimes curl up in very hot weather. 
The felt on their lower surface protects them from the attacks of the 
lace-leaf fly from which other Rhododendrons sulfer so seriously here. 
Hybrids of this plant with R. catawbiense hybrids which have been raised 
in England show no trace of the covering of felt on the lower surface 
of the leaves and are less hardy and less desirable plants here than 
their Caucasicum parent. In the Arboretum collection of Catawbiense 
hybrids are plants raised in England, the United States and Germany. 
English nurserymen have been longer engaged than those of other coun¬ 
tries in raising hybrid Rhododendrons and have had a larger variety of 
material to work with and as a rule the English Catawbiense hybrids 
are more desirable plants for this country than at least those in the 
Arboretum collection which have been raised in the United States and 
Germany. Nearly all the colors which have been obtained in the flowers 
of these hybrids will be found among the English plants which are hardy 
in the Arboretum. A list of such plants should include those called 
“Album elegans,” “Catawbiense Album,” “Charles Dickens,” “Atro- 
sanguineum,” “Caractacus,” “Lady Armstrong,” “H. W. Sargent,” 
“Roseum elegans,” “Mrs. C. S. Sargent,” “Henrietta Sargent,” 
“ Everest!anum, ” “Purpureum grandiflorum, ” and “Purpureum ele¬ 
gans.” With these if proper soil and a good position for the plants is 
selected a fine display of foliage and flowers can be obtained. 
