76 MASS. EXPERIMENT STATION BULLETIN 388 



and proliferation of roots. Roche 202 treatments gave variable results — from 

 to 100 percent rooting. As in the case of most treatments, best rooting was 

 at 65° F. 



Hormodin Powder No. 2 brought 83 percent rooting at 70° P., but fell to 66 

 percent at 65°. Hormodin Powder No. 3 gave best rooting at 65° — 100 percent. 

 Root development with powder treatments was much inferior to that produced 

 by immersion treatments of indolebutyric acid. The results with Hormodin 

 Powder No. 3 were generally paralleled by Formula No. 66. 



Tsuga canadensis vars. pendula and minima. Results of treatments suggest 

 these varieties propagate readih'. The records approximately parallel those for 

 T. canadensis. 



Tsuga canadensis var. Beaujean. Preliminary tests of twelve lots suggest that 

 this variety does not propagate so readily as those mentioned above. 



Generally, indolebutyric acid has shown definitely superior results to other 

 treatments in these trials and at low concentrations. A constant temperaure 

 of 65° F. appears optimum throughout the trials, with the exception of Hormodin 

 A at 30 BTI at 75°. Cuttings rooted best when taken soon after the first pro- 

 tracted cold weather of the season. 



Tests will be continued in 1941-42 with indolebutyric acid in vaiious forms at 

 minimum concentrations and optimum temperatures. 



Propagation of Mountain LaureL (Harold S. Tiffany, Waltham.) Preliminary 

 trials in 1940 gave indication of a low percentage of rooting from hardwood cut- 

 tings of mountain laurel, Kalmia latifolia, taken in mid-January. Treatment with 

 indolebutyric acid in the form of Hormodin A at 60 BTI units for 16 hours gave 

 20 percent rooting, while fairly high concentration of the salts gave only 10 

 percent. These roots developed in a sand medium; no roots developed in a 

 medium half sand and half peat, or in peat alone. 



Since successful propagation of the best white and deepest pink variations of 

 mountain laurel would be of decided value, a program of winter propagation 

 trials was carried out during 1940-41. Three series of cuttings were taken: 

 December 19-26, 1940; January 30-February 6 and March 13-20, 1941. Thirty- 

 eight treatments (plus other varied trials) in lots of six cuttings each for 'each 

 series were duplicated at constant temperatures of 65°, 70°, and 75° F., and in 

 an unheated bed averaging 60°. These were as follows: honey, 25 and 50 percent 

 solutions; Formula No. 66 and Hormodin No. 3; Hormodin A at 45, 60, 75, 90, 

 120, 150 BTI solutions; indolebutyric, indoleacetic, naphthaleneacetic acid salt 

 solutions at concentrations of 10 mg./lOO c. c. through 80 mg./lOO c. c. (10 unit 

 progression); Roche 202 at unit strengths of 50, 100, 200, 300; and an untreated 

 lot. 



While rooting percentages of the previous season's tests were perhaps slightly 

 bettered {33 percent), it appears from these results that the propagation of 

 mountain laurel from hardwood cuttings ma\' not be feasible. 



The twenty-eight plants rooted did not continue root development after 

 transfer to pots, seeming to hold only growth that had been made in the rooting 

 medium. The cuttings rooted in 1940 also exhibit an equal lack of normal 

 vitality. 



Propagation of Lilac. (Harold S. Tiffany, Waltham.) The time of taking cut- 

 tings of the common lilac, Syringa vulgaris var. Andenken an Ludwig Spaeth, 

 has been varied from May 28 to July 1. In no instance have rooting percentages 

 been as high as for those taken in late May at the time the flowers are about half 

 way into bloom. At this time the new growth is about 6 to 8 inches long, making 

 for good-sized plants when rooted. Rooting percentages of the 1200 cuttings 

 taken for test June 10, 1941, about two weeks after the optimum time, fell off 



