212 PRACTICAL PLANT PROPAGATION 



RH OD ODENDR ON Continued 

 Grafting in coldframes. 



"Briefly, I will explain how Rhododendrons can also be grown in 

 coldframes under double glass in Summer. By double glass I mean an 

 ordinary close fitting coldframe which is made for propagating pur- 

 poses. Inside of this coldframe another layer of sash is placed, so that 

 plenty of moist heat can be accumulated underneath the lower one. 



"The operations involved in growing the wild stock, or Rhododendron 

 ponticum, for propagating purposes are of course always the same. 

 Only the stock must be potted late in Spring for Summer propagating. 

 July is the time for grafting and plants receive nearly the same treatment 

 as if grown in the greenhouse in Winter. Only be a little more careful in 

 protecting the plants against the sun, as the leaves soon burn under 

 double glass. 



"The first week or so the grafted plants should not be disturbed at 

 all, and afterward the water, which gathers underneath the glass on the 

 inside sashes, should be allowed to run off, by daily lifting the sash for 

 a moment. In about three weeks the plants must be aired a little 

 every morning, and when another week is passed they must be moved, 

 some of the wild stock be cut off, and the new plants replaced in their 

 former position. 



"They should now be aired more freely every day, until the cion is 

 grown well onto the wild stock. When the plants are that far advanced 

 all the wild stock can be removed and the plants can be stood in an 

 upright position. The lower sashes are of no more use and can be taken 

 away entirely. 



"Leave the plants under single glass for another two weeks, then 

 these sashes can also be taken away. From then on, all they need is 

 protection from the sun, and, when Winter comes to be shielded from 

 snow and frost. 



"In Spring these plants can be planted in the nursery, at the same 

 time as the Rhododendrons which are propagated in the greenhouses 

 during the Winter." 



LAYERING. Speaking also of Rhododendrons, Van Cleef continues 

 in The Florists' Exchange, for May 26, 1917: 



"A large percentage of Rhododendron catawbiense, R. Cunninghami 

 and several other hardy kinds are produced by layering, as they form 

 roots more quickly by this method. 



"In growing Rhododendrons by layering it is advisable to select the 

 stockiest plants obtainable. If large specimens can be obtained they 

 are preferable, as they have many branches that can be used imme- 

 diately. Plant them with the intention of allowing them to remain in 

 the same place for several years, as parent plants should not be dis- 

 turbed. Use manure in abundance, and plant at such a distance that 

 the layers do not interfere with each other. Set the parent plants early 

 in the Fall, so that they have a chance to establish themselves thoroughly 

 before Winter comes. It is well to give them a little protection in 

 Winter, by strewing abundant manure around them to protect the 

 roots, and placing boards overhead to guard against frost and early 

 Spring sun. These boards can be removed in the middle of ^April, as 

 by that time the plants are pretty well used to the sun. 



"Time. The best time to layer Rhododendrons is in either early 

 Spring or Midsummer, before the sap begins to flow and after the first 

 growth has settled a little. Early Spring is preferable, however, as 

 the layers root more readily when the plant is actively growing, and 

 the soil is usually in a better condition as to moisture. By the time 

 the first growth is settled the weather usually is very hot and the soi 1 

 would have to be moistened artificially. One good rain does more goo d 

 than five artificial sprayings. 



