27 
some of them can be kept alive here for a great many years but they 
require special care. The soil in which they grow best has to be spec- 
ially prepared for them; they require shelter from the sun of early 
spring, and a great deal of moisture. Of late years they have suffered 
terribly from the attacks of the lace-wing fly which turns the leaves 
brown and makes them fall prematurely, thus weakening the plant. 
Rhododendrons, like many other plants of the Heath Family, cannot 
grow in soil impregnated with lime; they are not hardy very far north 
of Boston, and south of Philadelphia, except in the elevated regions of 
the interior, it is too hot for them in summer, so that the region in 
the eastern states where these plants can be grown at all is not a 
large one. Here in eastern Massachusetts there are only four species 
of broad-leaved evergreen Rhododendrons which are perfectly hardy; 
these are the native R. maximum, R. catawbiense from the high slopes 
of the southern Appalachian Mountains, R. carolinianum from the 
same region, and R. Smirnowii from the Caucasus, and if we can 
hope for a race of hybrid Rhododendrons better suited to the condi- 
tions of the New England climate than any we now possess, it will be 
obtained by mingling the blood of these four species and by excluding 
entirely the blood of the Himalayan species to which the garden Rho- 
dodendrons of Europe owe a large part of the brilliancy of their flowers. 
Rhododendron Smirnowii. This is a plant from which a good deal 
may be expected. It has been growing in the Arboretum for several 
years and has not suffered from cold or drought. When, however, the 
plant is fully exposed to the sun the leaves often droop and their 
edges infold, and it does better in partial shade. The leaves are pale 
grayish green above and below are thickly covered with pale felt 
which successfully protects them from the attacks of the lace-wing fly. 
The flowers are of good size and of pleasant shades of pink or rosy 
pink, and are borne in large clusters. As compared with the dark 
green leaves of R. catawbiense those of this plant are less attractive, 
but the flowers are much more beautiful in color and are equally large. 
Several hybrids of R. Smirnorvii with varieties of R. catawbiense have 
been raised in Europe, and there are a few of these in the Arboretum 
collection. They have proved to be good garden plants here, flowering 
earlier than R. Smirnowii and producing larger pink flowers; they 
have never been injured in the Arboretum, but as there is only a trace 
of the felt left on their leaves they will probably suffer from the lace- 
wing fly. Rhododendron carolinianum is said to have suffered last 
winter in a few places near Boston, but it was uninjured in the Arbor- 
etum and in several other Massachusetts gardens. It is the most 
beautiful of the dwarf small-flowered Rhododendrons which can be 
grown in this climate and may prove valuable to cross with other 
species. It has now been out of flower for more than two weeks. 
Rhododendron Smirnowii is now at its best. The flowers on R. cataw- 
biense are just opening, and those on R. maximum will not be out for 
another fortnight. The flowers of a few of the Catawbiense hybrids 
are in bloom but most Rhododendrons are late this year, and many of 
them are only beginning to show the color of their flowers through 
the opening bud-scales. 
