35 
faded, for they are of a disagreeable rose-purple color which has spoiled 
the flowers of many of its hybrids or of their varieties like the hardy 
and popular Everestianum. The flowers of R. carolinianum, one of the 
first species to flower here, are fast fading. This little shrub of the 
southern Appalachian Mountains, although distinguished only a few 
years ago, is becoming popular in northern gardens where it grows 
well under the shade of trees and in full exposure to the sun. It is a 
plant rarely three feet high, with small, dark green and compact clus- 
ters of pink flowers. There is a form with white flowers. The other 
Appalachian species, R. minus, blooms after the catawbiense hybrids. 
This shrub has been in cultivation for more than one hundred years, 
usually under the name of R. punctatum. Although a larger plant than 
R. carolinianum, with slightly larger pink flowers, it is not as good a 
garden plant for the flowers, like those of R. maximum, are hidden 
by the shoots of the year which rise above them. R. coriaceum, which 
came to the Arboretum thirty years ago from the Kanphill Nursery in 
England, resembles R. caucasicum of the mountain slopes of the Cau- 
casus. The shape of the leaves, the covering of brown felt on their 
lower surface, and the white flowers on long pedicels in few-flowered 
clusters do not greatly differ from those of the wild plant in shape and 
size. In the Arboretum R. coriaceum is now between three and four feet 
high and broad with erect stems; it flowers abundantly every year and 
the leaves and flower-buds are not injured by the cold of eastern Mas- 
sachusetts. It flowers, however, nearly two weeks later than the plants 
which are usually considered hybrids of R. caucasicum, although noth- 
ing very definite appears to be known of their origin. The best of 
these plants which have been grown in the Arboretum is called Boule 
de Neige and is believed to have been raised in France. It is a low, 
broad round-topped bush which is perfectly hardy and every spring is 
covered with flowers which are as white as it is possible for flowers 
to be. This is the earliest evergreen Rhododendron to flower in the 
Arboretum with the exception of the plant called Christmas Cheer, 
which is said to be a hybrid of R. caucasicum and the Indian R. arhor- 
eum, and every year loses its flowers by spring frosts. Boule de Neige 
is considered the handsomest and most satisfactory of the early-flower- 
ing Rhododendrons which can be grown in this climate. Almost as good 
is the plant called Mont Blanc with flowers which are pale rose color 
when the buds first appear but soon become pure white. The hand- 
some red-flowered Jacksohi too often loses the flower-buds in severe 
winters. The Caucasian R. Smrrnowii is as usual in good condition this 
spring and none of the Rhododendrons which can be grown here have 
more beautiful pink flowers. The thick coat of pale yellow felt which 
covers the lower surface of the leaves protects them from the attacks 
of the lace-wing fly which has in recent years done so much damage 
in this country and Europe to the leaves of Rhododendrons and Kalmias. 
A few hybrids of R. Smirnowii crossed with hybrid Catawbiense varie- 
ties have been raised and among them are plants of considerable prom- 
ise, although none of them retain the covering of felt on the lower 
surface of the leaves of their Caucasian parent. Still rare in American 
gardens, R. Smirnowii deserves the attention of planters of Rhododen- 
drons. It will probably prove valuable in breeding a race of Rhodo- 
dendrons suited to the climate of the northeastern United States. 
