1871.] NOTES ON RHODODENDRONS. 201 



are destroyed by spring frosts, and this even in the mildest seasons 

 and most favourable situations. For the full development of their 

 beauty, therefore, the shelter of a greenhouse is absolutely necessary ; 

 and they will richly repay their occupancy of the best place that can 

 there be assigned to them, as they are undoubtedly the most interest- 

 ing plants it can contain, especially during the spring months, either 

 while in bloom or making their new growths, when they are singularly 

 attractive and interesting. 



The conditions necessary for the successful cultivation of greenhouse 

 Rhododendrons are at once simple and easily supplied, and few plants 

 are less exacting upon the care and attention of the cultivator. 



In common with the outdoor members of the genus, they delight 

 in a rich fibrous peat soil, which, with the addition of more or less 

 sharp sand to make it sufficiently porous, alone should be used for 

 their cultivation in pots. 



In the preparation of the soil for potting, the turf should be chopped 

 down to the requisite fineness with the spade, so as to retain all the 

 fibre it contains ; and as it must be pressed as firmly round the ball 

 as possible, care should be taken that it be well aerated, and only used 

 in a dryish mellow state. To insure perfect drainage, a thin layer of 

 moss or rough peat should be put over the crocks before the finer soil 

 is introduced. 



The size of the shift must always be regulated by the habit and 

 vigour of the individual plant, as well as by the state of the roots. In 

 no circumstances is a large shift desirable ; it is far better that it 

 should be moderate, and repeated at such intervals as the growth of 

 the plant and the spread of the roots render necessary. Apart 

 from the importance of having them in as small pots as is consistent 

 with their real wants, there is the possibility of the soil, from the 

 necessity of frequent watering, becoming sour and sodden — a condition 

 most prejudicial to their health, particularly in the case of such as are 

 naturally slow-growing and weakly in their habit. In shifting, the 

 ball should never be disturbed more than is necessary for the removal 

 of loose soil, and on no account should the roots be torn off or muti- 

 lated. Of all the seasons of the year we prefer the spring for 

 repotting, immediately after blooming, and when they are beginning to 

 give indications of growth ; the roots then at once take to the fresh 

 soil, and the increased nutriment enables them to make rich luxuriant 

 shoots, and consequently full and well-developed flower-buds. 



During the growing season, the temperature of an ordinary green- 

 house, except in the cases of a few of the more tender kinds, will be 

 found amply sufficient; at this period they require an abundant 

 supply of water at the roots, and a frequent sprinkling overhead. 



