FORCING NATIVE PLANTS TO BLOSSOM 361 



these plants will force the best in a temperature that more 

 nearly approximates that in nature. 



An inspection of the column of the normal time of blooming 

 for this locality (Minneapolis) will show that the species tried 

 out can be forced to bloom anywhere from 11 to 17 weeks ahead 

 of time under the treatment given. 



It is reasonable to expect that better and more uniform re- 

 sults could be obtained with proper adjustments of tempera- 

 ture, watering, potting, etc., for in all cases tried very little 

 effort was made to take into account the different habitat and 

 soil conditions to which the plants have become adapted. The 

 results in one or two specific instances will illustrate the im- 

 portance of taking these things into careful consideration. 



The first year the experiment was tried, a flat planted with 

 Asarum canadense gave very satisfactory results. In this case 

 the plants were put in with the rhizomes practically on the 

 surface of the ground and only slightly covered with leaf mold. 

 During the second year a new set of plants was brought in, 

 and in planting, the rhizomes were covered with 1 to 2 inches of 

 soil. Only two blossoms came out and very few leaves were un- 

 folded. In the case of Pulsatilla very good results were obtained 

 the first year, but during the second year no flowers opened. In 

 the latter case, the flower buds were covered with a thin layer of 

 soil and in addition, the plants were watered too freely. Sev- 

 eral similar instances could be cited in addition to these, but this 

 is enough to show that care and judgment in potting and subse- 

 quent treatment must be exercised in order to insure success. 



The foregoing experiments are not comprehensive enough 

 to draw from them the conclusion that all our native perennials 

 can be successfully forced in the greenhouse during the winter 

 season. However, it has been clearh^ enough demonstrated that 

 a goodly proportion of them under proper treatment lend them- 

 selves to successful forcing and that a wealth of fresh material 

 can thus be obtained with little effort and expense. 



THE PLANT WORLD, VOL. 17, NO. 12, 1914 



