MOUND LAYERING 79 



by either bending the branch to the ground or by hilling up 

 the soil around the young shoots. The chief advantage of 

 layering lies in the fact that the parent plant supplies water 

 and food for the young plants until they are able to sustain 

 themselves. It also has the advantage of being an extremely 

 simple operation and of being more certain than most of 

 the other methods of vegetative propagation. Layering is 

 practised chiefly on the hard-wood plants, because her- 

 baceous plants are usually more readily propagated from 

 cuttings. Theoretically nearly all of the woody plants can 

 be multiplied by layering, but in practice this process is 

 confined for the most part to vines or to those plants having 

 long, slender shoots. The chief reason for the selection of 

 this class of plants is because of the ease in bending. Bending 

 is more easily performed on such plants as the brambles, 

 the grapes and occasionally the currants. Nevertheless 

 many similar plants are often increased by layering, and 

 even the apple, the quince and the pear may be so propagated 

 if the proper medium is supplied to the layering wood. In 

 layering, the roots are not, as a rule, developed in proportion 

 to the stem and their place of development is not prede- 

 termined, but is fixed by some external agent or stimulant, 

 as for example the contact with moist soil. Warm, moist 

 soil will act as a stimulus in some species and will induce 

 the formation of roots, while in other species and by far 

 the greater number, root formation is greatly facilitated by 

 the wounding of the stem where the new plant is wanted. 

 Such wounding causes adventitious buds to form. 



Mound Layering. — Occasionally the stems of plants cannot 

 be readily bent to the ground for layering. In such an 

 event a mound of earth is heaped about the plant, which 

 stimulates the formation of roots on the previously pre- 

 pared shoots, and this is called mound layering. Plants for 

 this purpose are usually first prepared by heading back in 

 the spring, with the result that a large number of young 

 shoots will be produced about the crown of the plant. The 

 following summer a mound of earth is placed about these 

 young shoots. Rooting will be facilitated if the shoots are 

 first injured in some way, as twisting, girdling or ring- 



