PLANTS FOR OUTSIDE PLANTING 425 



thoroughly harrowed. Asters are always propagated by 

 seeds and the best varieties should be selected. The 

 most general practice is to sow the seed in flats or pans in 

 the greenhouse in early spring. As soon as they have 

 germinated, the seedlings are transplanted to flats where 

 they are grown under glass until the season is warm enough 

 to place them in the frames. The plants should be put 

 into the coldframes as early as possible, that they may get 

 well hardened off before being placed in the field. There 

 is then little danger of the plants being chilled. 



That the early varieties may make a good growth be- 

 fore hot weather, it is advisable to set the plants in the 

 field as soon as all danger from severe frosts is over. 

 Plants which have been properly hardened will endure 

 slight frosts. The date for planting, therefore, is gov- 

 erned by climatic conditions; usually being about the 

 fifteenth of May. They are ordinarily so placed in 

 the field that they may be cultivated with a wheel hoe. 

 The rows should be about eighteen inches apart and the 

 early varieties may be placed from ten to twelve inches 

 apart in the row, while the later varieties should be from 

 twelve to fourteen inches apart. 



TUBEROUS-ROOTED PLANTS SUITABLE FOR OUTDOOR ORNA- 

 MENTATION AND FOR CUT-FLOWERS 



714. Cannas (Indian shot), botanical classification. - 

 Order, Scitaminacese (gingerworts) ; genus, Canna (name 

 of oriental origin, but of no special significance) ; the most 

 important species are : indica (a tall growing species 

 introduced into England about 1540) ; iridiflora ; flaccida ; 

 Warsceiciczii ; glauca ; speciosa ; and others. 



715. Varieties of Cannas. Cannas are now classed as 



