PROPAGATION OF TREES AND SHRUBS 31 



after treatment with naphthaleneacetic acid (30 mg./l., 12 hr.), the most 

 effective root-inducing substance for this species, 20 percent without it 

 (82). Similar cuttings responded to indolebutyric acid (2 to 5 mg./gm. 

 talc, or, by the concentrated solution-dip method, 4 mg./cc.) (49). 



Prunus glandidosa, dwarf flowering almond, is not difficult to propagate by 

 untreated softwood, July, cuttings (14, 44), made with the basal cut at 

 the base of the current season's wood (46) and planted in sand-peat (14). 



Prunus incisa can be propagated by softwood cuttings taken with a heel 

 early in the season or when the new shoots are about three inches long 

 (105). Rooting of late summer cuttings was improved by naphthalene- 

 acetic acid (25 mg./l., 24 hr.) (113). 



Prunus japonica. Late June cuttings, untreated, rooted about 50 percent 

 when made of tips, not basal parts, of young shoots (70). 



Prunus Laurocerasus, cherry laurel, is easily propagated by late summer 

 cuttings (7). Untreated cuttings taken here in early August rooted more 

 than 90 percent in sand-peat in seven weeks. January cuttings rooted 80 

 percent in 34 days after treatment with indolebutyric acid (40 mg./l., 

 6 hr.), not at all without treatment (119). 



Prunus maritima, beach plum. Softwood cuttings taken here in late June 

 failed to root without treatment. They rooted 43 percent in sandy soil 

 after treatment with indolebutyric acid (12.5 or 25 mg./l., 20 hr.), less 

 well in sand or sand-peat or if cuttings were taken later. 



Prunus Padus, European bird cherry. July cuttings rooted 32 percent with- 

 out treatment, 52 percent after treatment for 20 hours with a solution of 

 Auxilin containing indolebutyric acid 22 mg./l. (69). 



Prunus pseudocerasus. Softwood cuttings, made of entire young shoots, are 

 successfully taken when such shoots are about three inches long (105). 



Prunus subhirtella, Higan cherry. Softwood cuttings have been taken with 

 some success in early June (55). Taken here near the last of that month, 

 they did not root if untreated, but rooted 50 percent in sand-peat in 4 weeks 

 after treatment with indolebutyric acid (25 mg./l., 20 hr.). 



Prunus tomentosa. Hardwood cuttings rarely root but softwood cuttings 

 root fairly well (127) in sand-peat or sandy soil. Untreated cuttings rooted 

 63 percent in sand, 80 percent in sandy soil when taken here in late May, 

 less well if taken a month later. Rooting is better if most of the leaves 

 are left on the cuttings (126). Taken here in mid-June, cuttings rooted 

 100 percent in sand-peat in 3 weeks after treatment with indolebutyric 

 acid (40 mg./l., 6 hr.), 35 percent in 7 weeks without treatment. 



Prunus triloba, flowering almond. Cuttings root best if ma^le of new shoots 

 taken in spring (128) or when they are about three inches long (105). Root- 

 ing of July cuttings of the variety plena was improved by treatment with in- 

 dolebutyric acid (50 mg./l., 4 hr.) (125). 



Pseudotsuga taxifoUa, Douglas-fir. Late winter cuttings rooted 80 percent 

 in sand-peat after treatment with indolebutyric acid (50 mg./l., 24 hr.), 

 less well without treatment or when taken in fall and early winter (43). 



Pterocarya, wing-nut. The species, or some of them, can be propagated by 

 late-summer cuttings made of young shoots with a heel (80). Cuttings of 

 P. stenoptera rooted 90 percent in 3 weeks after treatment with Hormodin A 

 (20 B T I units), not at all meanwhile without treatment (118). 



Puerarta Thunhergiana, kudzu-vine. Cuttings are decidedly respotisive to 

 treatments with potassium permanganate. Those treated 30 minutes with 



