Complimentary 
NEW SERIES VOL. VIII 
NO. 12 
ARNOLD ARBORETUM 
HARVARD UNIVERSITY 
BULLETIN 
OF 
POPULAR INFORMATION 
JAMAICA PLAIN. MASS. JUNE 23. 1922 
Summer Flowering Shrubs. After the middle of June the number 
of trees and shrubs that bloom in the Arboretum rapidly decreases, 
but there are still the Lindens to flower, and the flowers of several 
shrubs make the Arboretum interesting in the last days of this month. 
The following are a few of the conspicuous plants at this season of 
the year: 
Rhododendron maximum, the only evergreen Rhododendron which 
grows in the northeastern states, with an extensive Appalachian range 
southward to Georgia, is one of the handsomest of the broad-leaved 
evergreen plants which can be grown in this climate. The flowers are 
pink and white or nearly white and, like those of some other late-flow- 
ering Rhododendrons, are more or less hidden by the branches of the 
year which usually make a considerable part of their growth before the 
flowers open. R. maximum grows well in any soil not impregnated 
with lime and flourishes in shade and when fully exposed to the sun, 
but when growing in open positions it is often seriously injured by the 
lace-wing fly which was first brought to New England on plants of this 
Rhododendron collected in the south. Hybrids of R. maximum and R. 
catawbiense hybrids have been raised. One of the earliest and best 
known of these hybrids, R. delicatissimum, has lustrous foliage and 
white flowers tinged with pink which open two or three weeks before 
those of R. maximum and are not hidden by young branches. This 
hybrid is one of the hardiest, handsomest and most desirable of the 
large growing Rhododendron which can be planted in Massachusetts. 
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