PLANTS FOR ROCKERIES. 



101 



G. pneumonanthe (Wind-flower), Britain ; height 

 6 to 12 inches ; tlowers deep blue : August. G. 

 septemfifla (Crested Gentian), Persia; height 6 

 to 18 inches ; flowers azure blue : June and July. 

 Position moist ; soil, sandy peat. G. verna (green), 

 Britain ; height 3 inches ; dense ; flowers blue, 

 and blue shades: April and May. Position dry; 

 soil sandy loam, with pieces of limestone freely 

 added ; fix firmly ; division and seeds. All the 

 Gentians are impatient of disturbance. 

 G ER ANIUM (Gran e' s- bill) . — G. cinereum (grey), Py ren ees ; 

 height 6 inches ; flowers pale red, with dark stripes. 



G. argenteum (silvery), Northern Italy ; height 3 

 inches ; flowers pale red : June and July. G. 

 cristatuin (crested), synonym. G. albanum, Tauria ; 

 height 12 inches ; flowers purple : May. G. lan- 

 castriense, Britain ; height, 9 inches ; striped : 

 June. G. sanguineum (bloody), Britain ; height 

 12 to 18 inches ; flowers blood red : summer. G. 

 striatum (streaked), South Europe ; height 12 to 

 15 inches ; flowers pink and veined : May to October. 

 Positions dry, common garden soil; division and seed. 



GypsoPHiLA REPENS (creeping), synonym. G. pros- 

 trata, Alps of Europe ; height 6 inches ; flowers 

 white and pale rose : July to September. Position 

 somewhat dry, soil loamy with mortar rubbish 

 or limestone, chippings added ; division, cuttings 

 , and seed. 



Helianthemtjm (Sun Rose). — H. formosum (Fig. 53), 

 also known as Cistus formosus, Portugal ; height 

 4 feet ; flowers yellow with black spot at base of 

 petals : summer. Position dry, sheltered parts of 

 rockwork ; calcareous loam ; cuttings and seed. 



H. ocymoides (Ocymum-like), South "Western 

 Europe ; height 1 foot to 3 feet ; flowers white, 

 yellow at the base : summer. Position warm and 

 dry, sandy soil, cuttings and seeds. H. tuberaria, 

 synonym globularisefolium (truffle sun rose), shores 

 of the Mediterranean ; forms large hairy leaves ; 

 height 9 inches ; flowers citron yellow : summer. 

 Position dry, fissure in the full sun, good soil. 

 Division and seed. H. vulgare (common sun rose), 

 Britain ; height 6 to 9 inches ; flowers yellow : 

 spring and summer. There are several varieties, 

 most of which can be raised from seed. Position 

 rougher parts of rockeries, common soil. 



HousTONiA COERULEA (Bluets), Virginia ; height 3 to 4 

 inches ; close growing ; flowers light blue, some- 

 times white, abundant : early summer. Position 

 sunny fronts, leaf soil and sand. 



HuTCHiNSiA ALPiNA (alpine). Central Europe ; height 

 1 to 3 inches ; flowers white : spring. Sunny 

 exposed position, sandy soil ; division and seeds. 



Iberis (Candytuft). — I. corifolia (coris-leaved), gar- 

 den hybrid ; height 1 foot ; flowers white : May 

 and June. I. gibraltarica (Gibraltar) ; height 1 

 foot to 2 feet ; llovvers white, suft'used with pink or 

 red : early spring. I. Tenoreana (Tenor's), South 

 West Europe ; height 6 inches ; flowers purplish 

 or whitish. I. sempervirens (evergreen), South 

 Europe ; height 9 to 12 inches ; flowers pure 

 white: spring and summer. Positions well ex- 

 posed, ordinary garden soil. Cuttings, divisions 

 and seeds. 



Iris (Flag). — I. cristata (crested), Eastern United 

 States ; height 6 inches ; flowers pale blue, throat 

 and crest deep yellow : April and May. Position 



Fig. 53. Helianthemuji FoEMOStrji. 



warm, open spots ; rich light soil ; oft'-sets and 

 seeds. I. nudicaulis (naked stem), synonym. I. 

 biflora, South Europe ; height 4 to 5 inches ; 

 robust ; flowers bright violet purple : April. 

 Ordinary garden soil ; division. I. pumila (dwarf), 

 Europe ; height 4 to 5 inches ; flowers bright lilac 

 purple: April. Position, flatter parts of rockwork ; 

 ordinary garden soil ; division of rhizomes. I. 

 pumila lutea, alba, coorulea and atro-cojrulea are all 

 good varieties. I. reticulata (netted). Southern 

 Europe ; height 3 to 6 inches ; flowers brilliant 

 purple : early spring. Position well-drained 

 slope ; sandy soil ; division of tubers and seed. 

 Leontopodium (Lion's-foot). — L. alpinum (alpine), 



