64 CALIFORNIA GARDEN FLOWERS. 



propagation have been handed down from most ancient times and consti- 

 tute an important branch of horticultural wisdom. It is encouraging, how- 

 ever, to the beginner to be assured that most plants do readily accept 

 multiplication by self-rooting or foster-rooting of severed parts, whenever 

 the gardener's art meets its humor, and therefore it becomes necessary to 

 know general conditions which are essential, also to study the way of the 

 plant one wishes to handle successfully. 



Next to knowing methods which meet the "disposition" or "affinity" of 

 the plant, the essential conditions to be provided are moisture and heat 

 followed by light, as the development of green tissues becomes desirable. 

 These are the same which secure the growth of a plant from a seed; in 

 fact, they are causative of all plant growth. The growth of a young plant 

 from the seed or from a severed part differs, however, from the general 

 vegetative action of an established plant from the very fact that it is not 

 yet established and furnished with tissues to sustain cell-action during tem- 

 porary adversity ; it can only hold life in its cells amid a favoring environ- 

 ment and during a certain period of time according to its own degree of 

 resistance and which is largely determined by its own disposition and 

 substance. 



The presence of adequate and yet not excessive moisture is a prime 

 requisite. The arch-danger of a severed part of a plant is "drying-out"; 

 another danger is "drowning out" the latter much the less, because certain 

 growths are favored by excessive moisture while others are ruined by it. 

 And this is true whether it be a cutting in the soil or a bud or scion in 

 place, for either of the latter may be dried up by a scant sap-flow or 

 "drowned" by too great a flow. All these facts show that for all severed 

 parts which are expected to grow inadequate moisture is destructive, and 

 excessive moisture may be. 



The second requisite, heat, is important, but variation in its occurrence 

 is less injurious. Still, the degree of heat favorable for different forms of 

 growth should be carefully heeded and arranged for. Heat in connection 

 with proper moisture causes cell-activity or growth, and the absence of a 

 proper degree of heat reduces the resistance of the tissues to decay germs, 

 which are always ready to invade and destroy them. 



Roughly, the relation of heat and moisture in the growth of a young 

 plant from a severed part of an older one may be stated in this way : 



The harder, or more dormant, the tissues of the cutting, bud or scion, 

 the less may be the moisture required to resist drying out, and the lower 

 the heat required to induce growth which may be deferred for some time 

 without injury. 



The softer, or more active, these tissues, the greater the moisture needed 

 to prevent drying out, and the higher the heat required to induce quick 

 start of growth processes which cannot be long deferred without inviting 

 decay of the tissues. 



