12 ROSTER COMPANY INC., BRIDGETON, N. J. 
RHODODENDRON CULTURE 
The importation of Rhododendrons from Europe was stopped in 
1919 by quarantine 37. Since then, Koster Nurseries have been pro¬ 
pagating Rhododendrons in large quantities, and during the past 20 
years have grafted over one-half million Hybrids. Our plants are 
known throughout the United States for their superior quality and 
hardiness. Our plants are grafted on hardy understock by expert 
propagators and must not be confused with inferior seedling types of 
Rhododendrons. They have been produced under open field culture 
and have compact tops and splendid root systems. If given the proper 
conditions, these healthy and vigorous plants will thrive without cod¬ 
dling or nursing. 
LOCATION. Rhododendrons can be grown in practically any 
situation with the exception of those spots entirely in the shade of big 
trees or on a steep bank facing south in the brilliant sunlight. In 
the former case, the plants are deprived of the sunlight essential to 
good health. While in the latter they suffer from drought during the 
hot weather, and sun injuries in the winter when the leaves are 
frozen. A northern, western or eastern exposure is especially desir¬ 
able as the plants are less likely to receive the direct winter sun on 
their frozen leaves. Cool, moist positions suit them best, and provided 
the ground is well drained, they will flourish in comparatively wet 
spots. Partial shade is very beneficial rather than otherwise, if it can 
be obtained without planting too near the roots of strong growing 
trees. The Rhododendrons on Koster Nurseries are growing out in the 
open fields in full sunlight and will thrive in quite adverse locations. 
SOIL. A well drained acid soil containing plenty of leaf mold 
is ideal for Hybrid Rhododendrons. In limestone or heavy clay soils it 
is necessary to trench the ground to a depth of two feet, discarding 
the ilmestone soil and replacing with good fibrous loam that has been 
mixed with decayed leaf mold or peat. For best results, one third fi¬ 
brous loam, one third peat or decayed leaf mold and one third rich, 
slightly acid top soil should be used. In the heavy clay soils, bottom 
drainage should be provided by using sharp sand or cinders. Fresh 
stable manure should be avoided in spring prepared soil but a good 
quantity may be encroached in the soil if it is done the fall previous 
to spring planting, 
PLANTING. The ground should not be too wet and the plants 
should be thoroughly trodded in when planting. If the soil can be 
properly prepared for Rhododendrons, it is impossible to tread Rhodo¬ 
dendrons too firmly since, when the root is removed the fibrous nature 
of the soil will make it rise right back up again. The plants should 
be planted at the same depth as they have been in the nursery or a 
trifle deeper. The ground mark on the stem being a sufficient guide 
for this. If the roots are at all dry, they should be thoroughly soaked 
before planting by standing them in water for one-half hour. One 
and one-half times their height is a good distance to plant Rhododen¬ 
drons apart. Here on Koster Nursery, plants two feet high are plant¬ 
ed about three feet apart. Planting can be done favorably during the 
months from September 1 to June 1, especially when the ground is 
frozen or very dry, 
CARE. Two year old or older grafted Rhododendrons are passed 
the difficult stage, and require only ordinary care. For established 
plants, a yearly top dressing of well rotted cow manure applied in 
November and covered with six inches of oak leaves will provide food 
that will maintain a healthy, vigorous ground during the next spring 
and summer growing season. The removal of flower set buds as soon 
as the booms are over, will promote growth and flowers for the next 
season. There are few enemies of Rhododendrons and their prevent¬ 
ion is easier than their cure. Towards this goal, the following spring 
campaign is highly recommended. A dormant, one per cent miscible 
oil spray applied in early March. A nicotine and soap spray applied in 
early May a,nd Borrdeau^ piixture plus arseni? lea^ applied in July, 
