78 MASS. EXPERIMENT STATION BULLETIN 388 



spring of 1940 and given a severe test the following winter without the benefit 

 of winter protection. 



The only 100 percent survivors after a winter during which a lasting blanket of 

 snow offered good protection, were the varieties Mme. Edouard Andre, Elsa 

 Spath, and Duchess of Edinburgh. Over 75 percent of Comtesse de Bouchaud 

 lived; 66 percent of Henryi; and 50 percent of Romona and montana var. rubens. 

 The species ascotiensis, crispa, langiUica var. obttisiuscula, and the varieties Belle 

 of Woking, Gipsy Queen, Mrs. Cholmondeley, Nelly Moser, Ville de Lyon, and 

 Ville de Paris were entirely winterkilled. 



While the number of plants was insufficient for a thorough test, and although 

 the test represents but a single winter, the hardiness of the plants of Mme. Edouard 

 Andre, Elsa Spath, and Duchess of Edinburgh is promising. 



Powdery Mildew on Garden Phlox. (Harold S. Tiffany, Waltham.) A spray 

 control program of Bordeaux mixture 1-1-50, Hammond's Copper Solution 

 1-150, Basi-Cop 1-50, and Wettable Sulfur 23^^-50 was applied to plantings 

 of Phlox paniculata from May to the time of flowering. Applications were 

 made at intervals of 7 to 10 days. 



Hammond's Copper Solution, with no residue, was again superior in both 

 control and appearance to Bordeaux Mixture, which left some residue on the 

 plants. Wettable sulfur gave better results than did Basi-Cop. 



Factors Influencing the Hardiness of Evergreens. (Harold S. Tiffany, Waltham.) 

 Records of terminal growth averages on Taxiis haccata repandens after the first 

 season of cultural treatments showed a definite correlation of growth with treat- 

 ment. Sod with no cultivation afforded fairly normal growth, yet the plants lost 

 much of this growth by the next spring. Cultivation wath no fertilizer gave a 

 normal amount of growth, and these plants suffered least from winter injury. 

 The spring application of nitrate of soda at the rate of 300 pounds per acre gave 

 the most growth, yet the plants were not injured comparably. As expected, 

 greatest winter injury came from manure, 15 tons per acre applied in May and 

 in August. 



Winter injury is calculated by (a) the number of terminals entirely winter- 

 killed, (b) terminals killed approximately two inches from tip down, (c) tip 

 injury to the bud with approximately ten needles killed, and (d) number of re- 

 tarded terminals after growth has started. After trying several methods of 

 measuring winter injury, this means appears to hold fairly constant. 



In 1941 additional fertilizer was given with the late August application of 

 manure for still further contrasts. A cover crop of annual r^'e grass was planted 

 in August on the nitrate of soda plot to check growth early and encourage harden- 

 ing after a rapid early growth. 



The dry 1941 season consistently lessened growth averages by approximately 

 25 percent. An exception to this was plants of Taxus canadensis stricta, which 

 showed more average growth than in the previous season in all plots. Explana- 

 tion may be that the plants had not become fully established at the end of the 

 first season of treatments, or that they withstand drought better than either 

 Taxus baccata repandens or Taxus cuspidata. 



Propagation of Mugho Pine. (Harold S. Tiffany, Waltham.) A series of cut- 

 tings of Mugho pine, Pinus mugo var. Mughus, was given preliminary tests in 

 1939-40, and the work for 1941 was based on the results of these tests. 



Lots of five cuttings each of one-year wood taken in January were placed in 

 open benches, in a rooting medium' of one-third peat and two-thirds sand, with 

 temperatures averaging 65° and 62° F. Dip treatments consisted of Formula 

 No. 66 and Hormodin No. 3; immersion treatments, of honey 25 and 50 percent 



