35 
little European species, there are only nine species of this great genus 
of several hundred species, hardy in this climate, and there is little 
hope that another species able to support this climate will be found. 
The poverty of our gardens in this plant appears when the Arboretum 
collection is compared with that in a garden in Cornwall in England, 
in which some three hundred and sixty species are growing and in 
which on a day in May sixty-five species have been in flower. Such a 
collection, and perhaps even a better one, can be made in a garden in 
the neighborhood of Portland, Oregon, or in some favorable place on 
the shores of Puget Sound, but the sooner it is realized that northeast¬ 
ern North America is not a good Rhododendron country in any broad 
sense the better it will be for the gardens in this part of the United 
States. For the last seventy years a large amount of thought, labor 
and money have been expended in attempts to cultivate these plants 
in the New England and Middle States; during this time many hun¬ 
dreds of thousands of these plants, principally hybrids of the Ameri¬ 
can R. catahwiense, have been imported from Europe but the collections 
of Rhododendrons in the eastern states at all satisfactory or compre¬ 
hensive can be counted on the fingers of one hand. In this climate 
unfortunately only a few of the Catawbiense hybrids, which are the 
popular Rhododendrons here, can be grown. The American parent of 
these hybrids is perfectly hardy, but the influence of the tender Him¬ 
alayan species with which it has been crossed has made most of the 
varieties of this hybrid unsuited to this climate. The influence of the 
tender R. poyiticum, the stock on which these plants have been almost 
universally grafted in European nurseries, may account in part for the 
fact that plants of these hybrids which have lived here for thirty or 
forty years have then died without any other apparent cause. If ever¬ 
green Rhododendrons are ever to become hardy and permanent features 
of eastern gardens we must give up trying to make European-grown 
plants successful here, and confine our efforts to the few species which 
are hardy here and to crossing these among themselves in the hope of 
obtaining hybrids which will be able to grow here permanently. Some¬ 
thing can be accomplished by the selection of seedlings For example, 
the flowers of R. catawbiense are of a peculiar shade of magenta which 
does not harmonize with any other color but white. Comparatively few 
seedlings, however, of R. catawbiense have ever been raised and prob¬ 
ably not much attention has ever been paid to selecting from among 
the plants growing on the high Appalachian peaks individuals with 
flowers of unusual colors. R. catawbiense is perhaps the hardiest here 
of all Rhododendrons; the habit is excellent and the leaves are hand¬ 
somer than those of the other hardy species. Improvement in the color 
of the flower is all that is needed to make it a first rate plant for this 
climate. It is doubtful if this can be accomplished by crossing it with 
other species, but through patient selection it may be improved and 
possibly a white-flowered form discovered. Hybrid Rhododendrons are 
hardier or less hardy than their parents. The few hybrids which have 
been made between R. catawbiense and R. maximum, the hardiest of 
all Rhododendrons here, are less hardy than their parents. On the other 
hand by crossing some of the Catawbiense hybrids with R. Metternichii, 
a delicate Japanese shrub, a race of hybrids has been produced in Eng¬ 
land which is quite hardy in the Arboretum; and the hybrids of the two 
