MODES AND PRINCIPLES OF PROPAGATION. 49 



advances the whole trench is filled. The rooting is from 

 the base of the new shoots as noted in mounding (51). 

 In the fall after the leaves drop, the layered shoots are cut 

 apart half way between the sets of growth. In spring 

 layering of single shoots and twigs the operation is usually 

 delayed until the bark will peel. A ring of bark is then 

 taken off at the point to be covered in pots or in the earth. 

 This favors more rapfd rooting, as the process of healing 

 'begins at once. But as a rule such plants as the grape, 

 climbing honeysuckle, tecoma, and passiflora put down in 



FIG. 20. Spring layering of the grape. 



spring will root without ringing or twisting. In spring 

 layering of branches of the rose, spiraea Van Houtteii, 

 and other shrubs, where the twigs were twisted before 

 laying down, it is found in autumn that many have not 

 rooted, but have formed a large callus. If such shoots are 

 made into callused cuttings and buried over winter they 

 will grow readily as cuttings the next spring. This is also 

 true of twisted summer layers that fail to root. 



In summer layering of the climbing roses and shrubs 

 the ones that callus and fail to emit roots will also grow 

 as cuttings if buried and planted the next spring. 



