338 THE NURSERY-MANUAL 



Hyssop (Hyssopus officinalis). Labiatce. 



Grown from seed sown in spring, either in drills where the plants 

 are to stand or broadcast in nursery-beds. It may also be prop- 

 agated from cuttings or division in spring or fall; greenwood 

 cuttings may be started in shade in early summer. 



Iberis (Candytuft). Cruciferce. 



The annuals and biennials are increased by seeds in spring or 

 autumn. Autumn-sown plants should be slightly protected during 

 winter ; these will bloom from spring to July while spring-sown plants 

 bloom from July to September. The sub-shrubby sorts are in- 

 creased by seeds sown in spring, and by divisions and cuttings 

 taken in September and put in sand, in a cold propagating-frame. 



Ilex (Holly). Aquifoliacece. 



Propagated by seeds, which should be stratified. They are often 

 cleaned of the pulpy coat by maceration. The seeds rarely ger- 

 minate until the second year. The evergreen species may be in- 

 creased by cuttings of ripened wood under glass. Varieties are 

 perpetuated by graftage. The veneer-graft, on potted plants, is 

 usually employed, but other methods may be successful. Budding 

 is sometimes practiced. /. Aquifolium and 7. opaca are mostly 

 used as stocks. 



Illicium. Magnoliacece. 



Increased by seeds ; also by cuttings of young ripened wood. 

 Imantophyllum : Olivia. 



Impatiens. Balsaminacece. 



Grown from seeds. The indoor species may be grown either 

 from cuttings or seeds ; cuttings usually root freely. See Balsam. 



Incarvillea. Bignoniaceas. 



Propagated by division and by seed. 



Indigofera (Indigo). Leguminosce. 



Multiplied by seeds, and by cuttings of young shoots under glass 

 in light heat and hardwood cuttings in winter. 



Inula. Composites. 



Seeds usually grow readily, giving blooming plants the second 

 year. Old plants may be divided. 



