40 Making a Rock Garden 



(P. veris), oxlip (P. elatior), bird's eye 

 (P. farinosa), yellow auricula (P. au- 

 ricula), P. denticulata, and P. Cor- 

 tusoides. Similarly, spring bulbs may be 

 employed ; plant them, for the most part, 

 under a ground cover so that the soil will 

 not show when they die down. Of the 

 tulips, single ones of the early and cot- 

 tage types may be used, if in a solid color, 

 but most to be preferred are the species, 

 such as the sweet yellow (Florentine) tu- 

 lip of Southern Europe and the little lady 

 tulip (Tulipa Clusiana). Crocuses are 

 also best in type forms, and the small, sin- 

 gle, yellow trumpet kinds are the finest 

 daffodil material. Single white or blue 

 hyacinths may be used, but better than 

 the stiff spikes of bloom of new bulbs will 

 be the looser clusters of bulbs that have 

 begun to " run out " in the border. Other 

 valuable bulbs are the snowdrop, Scilla 



