40 TREES AND SHRUBS 



usually budded or grafted on stocks of the parent 

 species. 



Ilex (Holly), Magnolia, Populus (Poplar), Platanus 

 (Plane), and Salix (Willow). The Holly is easily 

 raised from cuttings and layers, the second roots 

 readily when layered, and the latter three are pro- 

 pagated in large quantities by winter cuttings. The 

 White Poplar {Populus alba) is an exception, as this 

 can only be increased by root-cuttings. 



Increasing Hardy Shrubs 



The best of our hardy flowering shrubs are grouped 

 under seven natural orders, and a knowledge of the 

 order to which a plant belongs is in most cases a guide 

 to its propagation, as the majority of the species con- 

 tained in an order are, as a rule, increased by the 

 same methods. 



Berberide^. — This contains Akebia and Berberis, 

 which are propagated by seeds, cuttings, or layers. 

 Berberis stenophylla and B. Neuberti do not come true 

 from seed, so that one or both of the other methods 

 mentioned above must be adopted. 



Leguminos^. — In this order such genera as 

 Cytisus (Broom), Genista (Rock Broom), Spartium 

 (Spanish Broom), Ononis, Indigofera, Colutea (Bladder 

 Senna), Caragana (Siberian Pea tree), and Cercis (Judas 

 tree) should be raised from seed, which is the quickest 

 and best method of propagation. Cuttings of certain 

 forms of Cytisus and Genista will root readily, but 

 the plants will sometimes die off just as they have 



