CHAPTER X 
RHODODENDRONS FOR THE COOL 
GREENHOUSE 
Rhododendrons are very serviceable in the greenhouse 
and conservatory. When the Sikkim species were first 
introduced they were treated in many gardens as tender 
plants that required to be kept in a minimum tem- 
perature of about 45°. And it is surprising how many 
can be satisfactorily grown in this fashion, if their needs 
with respect to moisture and fresh air are not over- 
looked. Where the outdoor conditions are not favour- 
able to Rhododendrons, provision may easily be made 
for them under glass. This is done at Glasgow, in the 
Botanic Garden ; they have no chance in the open air, 
but a good collection is accommodated and well grown 
in the large winter garden. A house without hot-water 
pipes is suitable for all except the hardiest species, and 
of course the Javanicum race. Borders of light soil, 
liberal ventilation, with plenty of moisture, and shade 
from hot sunshine, are the essentials. If the plants must 
be grown in pots or tubs, it is quite easy to make a 
selection from the sorts that are generally known as green- 
house Rhododendrons. If possible, they should be placed 
out-of-doors for the summer. 
The following species and hybrids are recommended 
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