PROPAGATION OF TREES AND SHRUBS 39 



frame, rooted more slowl}' but as well finally as did fall and winter cut- 

 tings in a greenhouse (123). Sand-peat (14) or sandy soil (27) gave bet- 

 ter results than sand as a rooting medium. Cuttings of nine varieties of 

 American arbor-vitae responded to treatment with indolebutyric acid (40 

 to 80 mg./l., 24 hr., or 12 mg./gm talc) (61). Cuttings taken here in 

 January rooted 100 percent whether or not they were treated (100 mg./l., 

 16 hr.), but treated cuttings rooted in less time by about four weeks. The 

 only eflfect of treatment (80 mg./l., 20 hr.) of October cuttings of the 

 variety globosa and January cuttings of giant arbor-vitae was, similarly, 

 to hasten good rooting (125). November cuttings of the latter (var. 

 atrovirens) rooted 75 percent in about two months after treatment (50 

 mg./I., 24 hr.), 15 percent without it (57). Such treatments not only 

 hasten rooting but may also increase percentages which root finally. With 

 sandy soil as the rooting medium, cuttings of oriental arbor-vitae which 

 were taken here in December rooted 78 percent with treatment (50 mg./l., 

 24 hr.), 2i7 percent without it; and December cuttings of T. occidentalis var. 

 "Douglasii pyramidalis" rooted 100 percent with treatment, 62 percent with- 

 out it. 



Thujopsis dolabrata, Hiba arbor-vitae. Cuttings do not root readily, but 

 those taken in summer and treated with indoleacetic acid (50 mg./l., 24 

 hr.) rooted 45 percent more in 3 months than did untreated cuttings (113). 



Tripterygium Rcgelii. Hardwood cuttings taken here in late March, buried 

 in sand in a cold cellar for a month, and then lined out in the field, rooted 

 100 percent in 9 weeks whether or not they were treated. 



Tsuga canadensis, common hemlock. Cuttings, if treated, have rooted well 

 when taken in September or October (109), November (24), January 

 (125), March or April (61), and early summer, although early summer 

 cuttings, being soft, are difficult to keep in good condition (49, 126). 

 Summer (49), fall, and winter cuttings of this species (and T. Sieboldii) 

 responded to treatment with indolebutyric acid (40 to 80 mg./l., 24 hr., or 

 12 mg./gm. talc) (61). January cuttings rooted 79 percent in 62 days 

 alter treatment (50 mg./l., 22 hr.), not at all without it (125). Cuttings 

 of the variety pendula which were taken here in early September rooted 83 

 percent in sand-peat with treatment (50 mg./l., 24 hr.), 34 percent with- 

 out it. November cuttings rooted 5 percent without treatment, 65 percent 

 after treatment with indolebutyric acid (4 mg./gm. talc) (24). November 

 cuttings of a dwarf hemlock growing in southern Vermont and making not 

 more than one inch of new growth a year were here made with the basal 

 cut at the base of the two-year-old wood. Best results and most rapid root- 

 ing, 80 to 96 percent in sand-peat in 11 weeks, followed treatment with 

 indolebutyric acid, 100 mg./l., 16 or 24 hr., or 200 mg./l., 8 or 12 hr., 

 rather than lesser concentrations. There was at that time no root'ng 

 of untreated cuttings although all were still living. Summer (44) and 

 winter (125) cuttings have also rooted well in sand. 



Ulmus, elm. Oriental elms (124) and white elm can be propagated by soft- 

 wood, spring, cuttings. New shoots of Siberian elm, taken when they 

 were four to six inches long, rooted in 4 weeks (127). June cuttings of 

 that species and of Chinese elm rooted well in sand (44). Cuttings of 

 Siberian elm rooted best, more than 80 percent, with the basal cut a half 

 inch above the base of the current season's growth (46). Cuttings of 

 white or American elm taken here in early June rooted 94 percent in 5 

 weeks after treatment with indolebutyric acid (50 mg./l., 24 hr.), 23 per- 

 cent in 12 weeks without treatment. Cuttings of Siberian elm rooted 60 



