120 HARDY PERENNIAL PLANTS. 



succeed so well here as they do in the cool, moist countries of Europe. 

 Of the tall growing border kinds C. alliarigefoha reaches a height of from 

 2 to 3 feet; flowers white. C. medium, the Canterbury Bell, is a biennial 

 which, raised from seed one year, will flower the next. C. m. calycan- 

 thema has the calyx colored like the corolla, forming the well-known 

 cup and saucer arrangement. C. pyramidalis, although a perennial, is 

 best treated as a biennial. In a young state it should be given the pro- 

 tection of a frame during Winter, and if theplants are raised from Spring 

 sown seed they ought to be large enough to Winter in 5-inch pots. A 

 few should be kept for flowering in pots, as they make exceedingly hand- 

 some subjects for the decoration of the conservatory in Summer. C. 

 persicifolia is the most useful florists' flower in the genus. C. p. alba 

 grandiflora has very large pure white flowers. C. p. alba coronata pro- 

 duces white cup and saucer-shaped flowers. C. p. alba-plena is double 

 white, and while it lasts it is one of the best Summer white-flowering 

 plants. There are also single and double blue-flowered forms. All of 

 them grow about 2i/^ feet high. Plants which remain in the ground 

 over Winter will be benefited by a mulching around the crowns— of leaf 

 soil mixed with short manure. Of C. Trachelium there are double blue 

 and white-flowered varieties; height about 2i/^ feet. C. grandis and C. 

 g. alba are both good; height 3 feet. C. Van Houttei, a hybrid form 

 with dark blue flowers, grows about 2 feet high. Among the many 

 dwarf species C. isophylla and C. i. alba, blue and white, are trailers, 

 and where they succeed they may be used in baskets and vases, but they 

 do not thrive in very dry soil. C. carpatica is probably the most popu- 

 lar of the dwarfs; it is a plant which throws up a great number of 

 stems, forming a dense mound of compact growth usually about a foot 

 high, and when in full flower it is one of the most attractive of hardy 

 perennials. There are several forms having blue, pale blue, lilac and 

 white flowers. C. c. turbinata is dwarfer than the type; very suitable 

 for the front part of an herbaceous border, or for the rockery. C. rotun- 

 difoHa is rather an attractive species, but as a garden form C. r. Hostii 

 is an improvement. 



CATANANCHE CCERULEA— A plant with grayish green, long, narrow 

 leaves, and blue or blue and white flowers borne on long slender stalks. 

 It is of the easiest cultivation, and a desirable herbaceous plant. Sow 

 seeds late in the Fall and keep indoors; they will germinate very early. 

 Prick off into boxes and remove to a cold frame when large enough. 



CENTAUREA— Of this genus C. cyanus is the Cornflower and C. mos- 

 chata the Sweet Sultan. Both are annual in* duration. Seeds will ger- 

 minate in the open ground. C. americana is another good annual species 

 which is sometimes grown for Summer cut flowers; the color is pale 

 rose. C. babylonica is a good species to plant in the back part of an 

 herbaceous border; the foliage is silvery white; flowers thistle-like, 

 bright yellow. The plant reaches a height of from 6 to 12 feet. Increased 

 by division during the latter part of March. C. montana is the peren- 

 nial Cornflower, blooming during the greater part of Summer. There 

 are forms with lilac, rose, red, white and sulphur colored flowers. 



