10 FARMERS'* BULLETIN 826. 



After examining and regrubbing the different areas comprising the 

 68 acres of larkspur on the entire range selected in 1915, it was esti- 

 mated that the work had been at least 95 per cent effective. On one 

 area of 7.6 acres, containing both willows and open weed areas, only 

 125 plants could be found, against an original number estimated at 

 over 8,000. 



In regrubbing Plots 1, 2, and 3 during 1914 and 1915, it was found 

 that TO per cent of the plants came from roots which had not been 

 effectively grubbed, 25 per cent were seedlings, and 5 per cent were 

 mature plants which had been overlooked during former grubbing 

 operations. On Plots 2A, 3A, 4, and 5, regrubbed in 1916, 44 per 

 cent of the plants found were seedlings, 20 per cent were plants which 

 had been overlooked in grubbing the previous year, and 36 per 

 cent came from roots improperly grubbed. 



The plants coming from improperly grubbed roots showed lack 

 of vigor. They usually came from parts of roots which had been 

 split off from the main root in grubbing or from shallow lateral 

 roots which had been cut not more than an inch from where they 

 left the main crown. Several plants were dug, however, that came 

 from roots which had been cut off at least T inches below the surface 

 of the ground. AYhile most of the regrubbed plants were lacking in 

 vitality, they undoubtedly would have been able to hold their own 

 in competition with other species and produce seed. 



Extensive work in the eradication of larkspur by grubbing on 

 other National Forest ranges shows results only slightly less effective. 

 On the Fishlake National Forest, in Utah, larkspur was grubbed 

 from 55 acres in September, 1915, and June, 1916. Approximately 

 80 per cent of the larkspur was killed by the first grubbing. In 

 September, 1916, a careful examination of the grubbed areas showed 

 that approximately 90 per cent of the surviving plants were grow- 

 ing from roots which had not been eradicated completely. A large 

 percentage of the plants were growing from roots which had been 

 struck a slanting stroke, cutting one side of the plant only 1 inch 

 or less below the surface of the ground. Inefficiency from this cause 

 can readily be eliminated by greater care in the work of eradication. 



On the Sevier National Forest, in Utah, larkspur was eradicated 

 from an area of 5 acres in July, 1916. A careful examination of the 

 grubbed area in September, 1916, showed that approximately 90 

 per cent of the larkspur plants had been killed. Eighty-five per cent 

 of the plants still growing came from roots improperly grubbed. 

 Further examination of the work showed that where the grubbing 

 was done after the men had had some experience 95 per cent of the 

 plants were killed. 



On the Durango National Forest, in Colorado, larkspur was 

 grubbed from an area of 55 acres, in September, 1915, and from 



