PROPAGATION OF TREES AND SHRUBS 37 



20 percent without treatment but they rooted 88 to 100 percent in sand-peat 

 in 8 to 10 weeks after treatment with indolebutyric acid (50 mg./L, 20 

 hr.). Sand (105) and sandy soil (7, 80) have also been used successfully. 

 To induce more of the rooted cuttings to live through the first winter, 

 sometimes difficult, they should be kept in a warm place and, if possible, 

 growing (105). 



Styrax. S. japonica is not usually propagated by cuttings (104), but un- 

 treated softwood cuttings of that species, 5". americana, and 6". Obassia rooted 

 well if taken here in mid-July, less well if taken in late August. Taken here 

 in late July, untreated cuttings of S. japonica rooted 40 percent in sand, 80 

 percent in sandy soil; and those which had been treated with indolebutyric 

 acid (12.5 mg./L, 18 hr.) rooted 50 percent in sand, 90 percent in sandy 

 soil. Such treatments sometimes merely hasten rooting. Cuttings of 

 S. japonica rooted 1()J pe-Ccut in 8 weeks wilhuut h-eatment and in 3 weeks 

 after treatment (indolebutyric acid 50 mg./L, 4 hr.) (125). December 

 cuttings of S. americana responded to treatment with 4 mg./cc. applied by 

 the concentrated solution-dip method (49). 



Syiiiphoricarpos can be propagated by cuttings of hard or soft wood (51). 

 Untreated cuttings of snowberry rooted well when taken in June, July, and 

 August (44). Similar cuttings of coralberry, untreated, rooted 100 per- 

 cent and best with the basal cut a half inch above the base of the current 

 season's growth (46). Late June cuttings of that species rooted, in 3 

 weeks, 93 percent after treatment with indolebutyric acid (5 mg./L, 24 hr.), 

 27 percent without it (57). Softwood cuttings of snowberry rooted better 

 in sand than in sand-peat, better at 70° F. than at 60° or 80° (116). 



Symplocos paniculata, Asiatic sweetleaf, has been considered difficult to 

 propagate by cuttings (98). Softwood cuttings taken here in early June 

 rooted 58 percent in sand with treatment, 36 percent without it; and 

 similar cuttings in sandy soil rooted 92 percent with treatment (indole- 

 butyric acid 50 mg./L, 24 hr.), 55 percent without it. 



Syringa, lilac. Cuttings of 6". vulgaris root best if taken in spring, May or 

 June here, while new shoots are still growing (49) or very soon after 

 flowering (67, 78, 125). Being very soft, they must be carefully protected 

 against wilting; but taken later, when the wood is harder, they root more 

 slowly and usually in smaller percentages (60). Cuttings taken as late as 

 July are less likely to make good top growth that season (46). Good 

 cuttings are made of shoots, not too vigorous (106), which are not more 

 than six inches long (45). Complete shoots, with the basal cut at the 

 base of the current year's growth (46), root better than parts of shoots 

 (60). 



Lilac cuttings root well in sand (78), better than in sand-peat (44, 56, 

 116). They should be inserted at an angle so that the leaves are almost 

 flat on the sand (45, 60). Shading is more than usually important for 

 such very soft cuttings. Bottom heat has been recommended and cut- 

 tings of two species rooted better at 70° F. than at 60° F. (116). 



The optimum concentration of indolebutyric acid is not exactly the same 

 throughout the season (cuttings taken early are likelj^ to need a some- 

 what greater concentration than those taken two weeks later), nor is it 

 exactly the same for all horticultural forms of 5". vulgaris (60). But their 

 rooting, and tlie rooting of cuttings of other species (60), is usually im- 

 proved by treatment with 20 to 60 mg./L, 24 hr., 2 to 12 mg./gm. talc, or, 

 by the concentrated solution-dip method, 4 to 10 mg./cc. (49). Taken 

 here in mid-June, cuttings of Marie Legraye rooted 22 percent without 



