Complimentary 
NEW SERIES VOL. II 
NO. 9 
ARNOLD ARBORETUM 
HARVARD UNIVERSITY 
BULLETIN 
OF 
POPULAR INFORMATION 
JAMAICA PLAIN, MASS. JUNE 23. 1916 
Summer-flowering American Viburnums. For many flowers the 
Arboretum is indebted in early summer to four American species of 
Viburnum which have been used in large numbers in its borders and 
roadside plantations. The earliest of these, V. dentatum, is already in 
bloom; it has handsome dark green leaves conspicuously toothed on 
the margins, and broad flat clusters of white flowers which are followed 
in early autumn by bright blue fruits on erect stems. This is a com- 
mon roadside and meadow shrub in the northeastern part of the coun- 
try. The second of these four Viburnums, V. cassinoides, is also in 
bloom. It is a native of swamps in the northeastern part of the coun- 
try where it sometimes grows twenty feet high with slender straggling 
stems. In cultivation it forms a broad, low, round-topped bush, and 
has proved one of the handsomest of all the Viburnums introduced in- 
to the Arboretum. The leaves are thick and lustrous and vary greatly 
in size and shape. The flowers are slightly tinged with yellow and 
are borne in wide slightly convex clusters which also vary greatly in 
size. The fruit is larger than that of the other summer-flowering 
American species, and at first yellow-green later becomes pink, and 
finally blue-black and covered with a pale bloom, fruit of the three 
colors occurring in early autumn in the same cluster. In the Vibur- 
num Collection, near the junction of the Bussey Hill and the Valley 
Roads, there are a number of plants of this Viburnum selected to 
show the variation in the shape of the leaves and in the size of the 
flower-clusters. The third of these summer flowering Viburnums, V. 
venosum, resembles in its general appearance V. dentatum but it flow- 
ers two weeks later, and the young branchlets and the lower surface 
of the leaves are thickly covered with a coat of stellate hairs. This 
Viburnum is found growing naturally only in the neighborhood of the 
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