Desirable 

 I j Intermediate 

 Less desirable 



Amitrole Picloram Glyphosate Triclopyr 



Rototilling 



Desirability Class by Treatment 



Figure 2 — Community response after 9 years to control treatments 

 for false hellebore by desirability class. 



Disc 

 chaining 



DISCUSSION 



These data suggest that rototiUing produced the most 

 immediate and sustainable reduction of false hellebore. 

 A possible disadvantage is that rototilling is limited 

 to areas accessible by a tractor and to areas with a 

 hmited amount of rock in the top 20 cm of the soil 

 profile. In addition, some form of reseeding will be 

 required afterward, since the weedy vegetation that 

 becomes estabUshed otherwise is Uttle better than the 

 initial false hellebore patch. Tarweed (Madia glomer- 

 ata) was the dominant replacement species after this 

 treatment. The disc chaining treatment produced a 

 similar response; false hellebore stem density was re- 

 duced substantially, but the species replacing it were 

 often undesirable. 



The control achieved by herbicides appeared to be 

 greatest within the first 2 posttreatment years, declin- 

 ing afterward. All of the herbicide treatments would 

 Ukely have been enhanced by reseeding. A vigorous 

 reseeding would probably suppress the recovering false 

 hellebore stand and improve the composition of the 

 posttreatment plant community. The results ft-om 

 this study indicated no significant differences between 

 the degree of control achieved by the different herbi- 

 cides (a = 0.05); however, the picloram treatment re- 

 duced stem density the most after 9 years. Posttreat- 

 ment community structure was also similar among 

 these treatments with a large majority of the species 

 being classified as having either desirable or interme- 

 diate qualities. 



The cutting treatment did not appreciably control 

 the stem density of false hellebore, although a reduc- 

 tion in canopy height and plant vigor was observed 

 during the first years following treatment. A foUowup 

 defoliation treatment may have killed these plants, 

 which were already under apparent stress fi-om the 

 first treatment. The treatment appeared to have 

 stimulated stem production by 1991; hand cutting 

 was the only treatment that produced higher stem 

 densities in 1991 than existed before treatment. 



The lack of true replication in this study precludes 

 definitive conclusions from being drawn; nor can spe- 

 cific applications be recommended for a variety of sites. 

 However, because data relating to control of false helle- 

 bore are so limited, managers have little information 

 on which to base management decisions. Data from 

 this study may provide useful information for control 

 efforts. The nearly 10-year data base helps evaluate 

 treatment longevity. Further work in this area is 

 necessary to provide a better understanding of con- 

 trol options. 



CONCLUSIONS 



Final selection of a control methodology should be 

 made afl^er carefully analyzing the costs of each treat- 

 ment and the potential for recovery of the native com- 

 munity. Where logistically and financially feasible, 

 rototilling or some other treatment that disrupts false 

 hellebore's rhizome would appear to be the best alter- 

 native for control; however, after such a disturbance 



5 



