Plants for a Rock Garden 37 



plants, like certain friends, you enjoy hav- 

 ing for a visit, but do not care to see re- 

 main forever and a day. 



Annuals as a class are not desirable for 

 the rock garden; for one thing, the care 

 of renewal is too great. Biennials are al- 

 most as much care, but in each case there 

 will always be exceptions that are a mat- 

 ter of individual preference. Few, for 

 example, would have the heart to reject 

 the dainty little purple toadflax of 

 Switzerland (Linarla alpina), just be- 

 cause it is a biennial. The main depend- 

 ence, however, must be placed on peren- 

 nials the plants that, barring accidents, 

 last indefinitely. These should be mostly 

 species; if horticultural, do not use the 

 bizarre Darwin tulips, for example, or 

 the Madame Chereau iris. Nor, with rare 

 exceptions, should double flowers be used. 

 A double daffodil looks horribly out of 



