42 TREES AND SHRUBS 



are best worked on stocks of the species they 

 belong to. 



Cralcegus (Thorn), Catalpa, and Robinia (Locust 

 tree), can be raised from suckers or root-cuttings, 

 if seeds cannot be got. Any of their varieties are 

 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^E. This contains Akebia and Berberis, 

 which are propagated by seeds, cuttings, or layers. 

 Herberts 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, Indigo/era, Colutea (Bladder 



