50 MASS. EXPERIMENT STATION BULLETIN 428 



experienced a wet previous summer and fall, a dry previous summer and fall, a 

 winter with almost no snow, a winter with plenty of snow, mild winter tempera- 

 tures, and severe cold winter temperatures. Records of the winter injury on 

 each plant were made each spring, and it was found that there was no correlation 

 between slow growth and winter injury. Each plant has shown injury at least 

 once, and some have shown it after each winter. In all cases injury appeared in 

 the spring, usually in April and two or more weeks after prolonged strong winds. 

 To determine whether wax sprays would prevent winter injury, several plants 

 of Globe arbor vitae were sprayed late in the fall with Dowax 1 part to 4 parts of 

 water. None of the plants showed winter injury, although all plants had been 

 injured in previous winters. 



Study of Herbaceous Perennial Material. (C. J. Gilgut, Waltham.) In the 

 study of cultural requirements and winter hardiness of herbaceous perennial 

 plants, no mulch was used during the winter. There was a good cover of snow 

 and perhaps for this reason fewer plants were lost from winterkilling than during 

 the previous winter when there was no snow and a hay mulch was put on after 

 the ground froze. 



Bearded iris when divided and transplanted about one month after flowering 

 suffered less seriously from winter injury and produced better flowers the follow- 

 ing year than when transplanted later in the season. 



Professional gardeners, landscape men, nurserymen, and the general public 

 continue to visit the gardens regularly to become better acquainted with the 

 newer and better garden plants. Of the thirty-six new acquisitions placed in the 

 gardens for test, many have not been introduced or disseminated to the gardening 

 public. Numerous requests, by visitors and through the mail, for information 

 on varieties, cultural requirements, fertilizers, and suppression of insect pests 

 and fungous troubles were answered during the season. 



DEPARTMENT OF OLERICULTURE 

 G. B. Snyder in Charge 



Weed Control in Fields of Carrots and Parsnips. (W. H. Lachman.) It has 

 recently been found that certain oils sprayed on fields of carrots and parsnips 

 would destroy weeds without harming these crops. Rather extensive experiments 

 at the college as well as many cooperative tests by vegetable growers throughout 

 the State have indicated the value of this method for controlling weeds. 



Oils which, in general, pass the specifications for "Stoddard Solvent" have 

 given good weed control with no deleterious results. Some of the materials which 

 pass these specifications are: Mineral Spirits, Naphtha No. 52, Sovasol No. 5, 

 Stoddard Solvent, Sun Spirits and Varsol No. 2. Another oil, Sovasol No. 75, 

 was found to be a good selective weed killer when mixed with two parts of white 

 kerosene. These oils are used in industry as paint thinners, for dry-cleaning 

 clothes, and as solvents. They seem to be highly selective for members of the 

 Umbelliferae family such as carrots, parsnips, celery, and parsley. The leaves 

 of celery and parsley, however, seem to be more sensitive and under some con- 

 ditions are severely burned by these oils. The sprays completely destroyed young 

 beet and turnip plants. 



Best results were obtained if the oil was applied when the weeds were small 

 and succulent. On a clear, warm day the weeds were often wilted within a half 

 hour after spraying and were dead the next day. Almost all of the common weeds 

 encountered have been completely controlled, with the e.xception of ragweed, 



