Complimentary 
NEW SERIES VOL. IX NO. I 
ARNOLD ARBORETUM 
HARVARD UNIVERSITY 
BULLETIN 
OF 
POPULAR INFORMATION 
JAMAICA PLAIN. MASS. MAY 1. 1923 
Compared with those of recent years it is a “late spring” in the 
Arboretum after a winter remarkable in the large amount of snow 
which has fallen and which has covered the ground continuously from 
the middle of December to the middle of March. The deep cover of 
snow has successfully protected low growing plants; it has protected, 
too, field mice which have injured some valuable shrubs by stripping 
the bark from their stems and branches. The cold was not unusually 
severe. Covered by the deep snow the ground was free or nearly so 
of frost during the winter, and in March there was promise of an ex¬ 
ceptionally early spring, but on the morning of March 29th the ther¬ 
mometer registered two degrees below zero and the prospect of an 
early spring was ended. Fortunately this extreme cold at the end of 
March had not been preceded by days of high temperature, and com¬ 
paratively little damage to plants in the Arboretum was caused by it. 
Rhododendrons with persistent leaves have suffered here more than any 
other plants by the low temperature at the end of March. There are 
dead branches on many plants of the Catawbiense Hybrids which have 
grown uninjured here for years; and some of the large plants of the 
native Rhododendron maximum have suffered even more than the Cataw¬ 
biense Hybrids. The hybrid Rhododendron myrtifolium {R. hirsutum x 
minus) which has been growing in the Arboretum since 1885 and has 
never before lost a leaf or a flower-bud, is now badly injured. It is 
interesting that a related hybrid, R. arbutifolium, the R. Wilsonii of 
many gardens {R. ferrugineum x minus) is uninjured, as is R. minus it. 
self. Uninjured, too, are R. catawbiense, the Caucasian R. Smirnozii, 
the Japanese R. Metternichii, and R. Wateri, the hybrid of one of his 
1 
