PROPAGATION OF HARDY TREES 39 



shrubs, and later on for evergreens. The actual 

 time depends upon the season. 



Where seed is not expressly mentioned below, it 

 must be understood that this is the natural, and in 

 many cases the best, way to propagate. 



The following trees can only be raised from seed 

 to do any good afterwards, though a few of them 

 will throw up suckers, which can be taken off and 

 replanted : sEsculus (Chestnut), Ailantus, Alnus 

 (Alder), Arbutus, Betula (Birch), Carpinus (Hornbeam), 

 Carya (Hickory), Castanea (Sweet Chestnut), Celtis 

 (Nettle tree), Fagtis (Beech), Fraxinus (Ash), Gledits- 

 chia (Honey Locust), Juglans (Walnut), Laburnum, 

 Liquidambar, Morus (Mulberry), Prunus, Pyrus, Quercus 

 (Oak), Sophom, Ulmus (Elm), and Zelkova. The varie- 

 ties of any species of the above, and, in fact, of nearly 

 all hardy trees, must be budded or grafted on the 

 species they are forms of, but an exotic species 

 should never be worked on the native representative 

 of the genus e.g. ALsculus flava should not be budded 

 on the Common Horse Chestnut, as the latter is far 

 too strong a stock for the smaller-growing -^Esculus. 



Acer (Maple) and Tilia (Lime or Linden) can be 

 raised from seeds or by layering, the Lime especially 

 being largely propagated from layers, which soon 

 form strong young trees. The varieties of Maple 

 are best worked on stocks of the species they 

 belong to. 



Cratcegus (Thorn), Calalpa, and Robinia (Locust 

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

 if seeds cannot be got. Any of their varieties are 



