NEW AND BEAUTIFUL ROCK PLANTS 105 



planted for July flowering ; villosum is another good 

 summer-blooming yellow species. Ordinary soil. 



HOUSTONIA CffiRULEA. A minute plant with pale 

 blue flowers in late spring ; there is a white variety, alba ; 

 the species serpyllifolia has lavender flowers in May, 

 but there is also a white form. Ordinary soil. Propaga- 

 tion by division. 



; HUTCHINSIA (NOCC^JA) ALPINA. A low-growing 

 white Alpine, blooming in spring. Any light soil. Propa- 

 gation by seeds in spring. 



IBERIS (PERENNIAL CANDYTUFT). Valuable 

 plants, owing to their adaptability to various soils, 

 vigorous growth, and abundant blooming. Semper- 

 virens is perhaps the best known of the perennial rock 

 Candytufts, and of this there are several good varieties, 

 such as plenum (double), superba, Perfection, Snow- 

 flake, Climax, Little Gem and Garrexiama ; all are white- 

 flowered ; the last is one of the best, as the flowers are 

 very large. Gibraltarica is very popular, with its pale 

 pink flowers, but it is not perfectly hardy ; and 

 corifolia, with large white flowers in early summer, 

 evergreen, is also widely used. Jucunda, three inches 

 high, with pink flowers in May, is less familiar than the 

 others named. Propagation by seeds and cuttings in 

 spring. Ordinary soil. 



IRIS. See Border Plants. The smaller Irises, such as 

 persica, reticulata, histrio, histrioides, pavonia (Peacock 

 Iris, not hardy), Gatesii, Bucharica, sisyrinchium, Sind- 

 jarensis and pumila, are well adapted for the rock garden. 



LEONTOPODIUM ALPINUM (EDELWEISS). Too well 

 known to need description. Quite easy to grow, but 

 liable to die out in wet winters unless protected with 



