170 THE PRINCIPLES OF FLORICULTURE 



given, cell development is checked, and the cutting be- 

 comes hard and woody. Rapid growth cannot go on, and 

 the young plantlet becomes stunted and weakened. Cut- 

 tings should never be left too long in the propagating 

 bench. 



REPRODUCTION BY GRAFTING 



Within recent years, reproduction by grafting has come 

 into popular favor in greenhouse work, particularly with 

 rose-growers. For many years, all roses forced were 

 grown on their own roots. There was an apparent lessen- 

 ing of vitality in the plants and consequently a lower pro- 

 duction. 



An attempt was made to graft tea roses and hybrid teas 

 on various kinds of native rose stocks. After many fail- 

 ures, a satisfactory union finally resulted from the cions 

 on the manetti stock. This stock is grown extensively 

 in England, Scotland and France. This method of grafting 

 roses was first introduced by Alexander Montgomery at 

 the Waban Rose Conservatories in Natick, Massachusetts. 

 135. Advantages of grafted rose stock over own-root 

 stock. For several years, there has been much contro- 

 versy between the advocates of using grafted stock and 

 those of using own-root stock. A consensus of opinion 

 favors grafted stock. The reasons are as follows : 



(a) Freedom from attacks on roots by nematode worms. 

 Attacks from nematode worms are very likely 

 to occur when roses are grown on their own roots. 

 This rarely occurs on grafted stock, hence healthy 

 plants are produced and a consequently larger 

 output is assured. 



(6) A longer blooming period because of increased 

 vitality in the root system, so that plants may 



