12 MASS. EXPERIMENT STATION BULLETIN 382 



affect their rooting (50), but that when a solution 1:1,000,000 was used to 

 water sand in which treated cuttings of Japanese yew and Pfitzer juniper 

 had been planted twelve days previously, their rate of rooting was sig- 

 nificantly increased (103). Vitamin B,i, in a solution of 1:5,000,000, sim- 

 ilarly applied to sand once a week, hastened rooting and caused cuttings 

 to retain leaves better in the case of about one-third of the species with 

 which it was used (98). 



In anj^ case, or without regard to the explanation, the addition of loam 

 to sand has a good effect on rooting of cuttings of some species. Whether 

 or not the results would be even better if the loam were first sterilized 

 was not determined, but the risk of trouble from that quarter may be 

 less great than might be expected. It is interesting to note that cuttings 

 of woody plants sometimes root better in old sand — sand which has been 

 used for rooting cuttings and is probably contaminated, certainly not 

 clean — than they do in new, fresh sand (113), and that cuttings of azaleas 

 (44) and Erica (105) rooted better in a medium in which they had pre- 

 viously been rooted or grown than in one freshly prepared. 



Insertion of Cuttings and Their Subsequent Care 



Cuttings are inserted firmly in the rooting medium, usually as deeply as 

 possible without burying the leaves. Leafy cuttings of most woody plants 

 are likely to do best if inserted slantingly, not vertically, for, in the slant- 

 ing position, inore of the leaves are near or upon the rooting medium 

 where there is less danger of the air being too dry. If there is much top 

 growth before rooting or transplanting, cuttings so set may not have 

 straight stems, but that risk is slight except with the most actively grow- 

 ing material. 



To help prevent wilting, cuttings in bench or frame are usually shaded 

 with cheesecloth or whitewashed glass and sprinkled with water several 

 times a day, a practice which is likely to give better results than heavier 

 and less frequent waterings. Good temperatures of the air are 70° to 80° 

 F. days, 60° to 65° F. nights (130). Bottom heat, 70° to 72,° F. often 

 hastens rooting (49). It was used here in fall, winter, and spring but, 

 because of high air temperatures, not in summer. Bottom heat at 70° to 

 75° F. gave better results than at 80° to 85° F. with cuttings of Japanese 

 yew and Pfitzer juniper (103), and temperatures of 75° to 80° F. are known 

 to be too high for best rooting of cuttings of some other species (49;). 



The most effective temperatures for rooting treated cuttings are between 

 70° and 80° F. and root-inducing substances are without much eft'ect if 

 cuttings, after treatment, are given a low temperature (49, 58), 60° F. or 

 lower (61). 



Treated cuttings need no less care than untreated, although, if treat- 

 ment is effective, they may not need it for so long a time. 



Results with Individual Species 



Abelia grandiflora. Softwood cuttings root readily, but treatments with 

 indolebutyric acid (10 mg./L, 24 hr., or 2 mg./gm. talc) (61) may hasten 

 rooting. Taken here in early August, they rooted 100 percent in 7 weeks 

 without treatment, in 4 weeks with treatment (12.5 mg./l., 24 hr.). Root- 

 ing of July cuttings was similarly hastened by treatment with Hormo- 

 din (102). 



