336 THE NURSERY-MANUAL 



bloom. These cuttings are slips (page 107) of the growing wood. 

 See the various species, under their respective heads. 



Hovenia. Rhamnacece. 



Propagated by seeds, cuttings of mature wood struck under 

 glass, and also by root-cuttings. 



Howea (commonly known as Kentias). Palmaceoe. 



Increased by seeds in light soil, with heat. See Palms, page 

 377. 



Hoya (Wax-Plant). Asclepiadaceoe. 



Handled by layers and cuttings. The common wax-plant, H. 

 carnosa, is readily propagated by layering ; the long shoots make 

 roots naturally. Cuttings may be taken in spring of firm wood. 

 Some species may be grafted on stronger-growing kinds. 



Humulus : Hop. 



Hunnemannia. Papaveracece. 



Grown from seed; in the East seeds sown early in May give 

 bloom in summer. 



Hyacinthus (Hyacinth). Liliaceoe. 



For the production of new varieties seeds are employed. These 

 are sown the same season they mature, in light sandy soil, and are 

 covered not more than ^ inch deep. In four or five years, or 

 sometimes even longer, the bulbs will be large enough to flower. 



Varieties are perpetuated by means of the bulbels, which form 

 freely on some varieties. These are treated in much the same way 

 as mature bulbs, or they may be handled in pans or flats. They 

 make flower bulbs in two or three years. To increase the numbers 

 of these bulbels, the bulbs are variously cut by the Dutch growers. 

 These practices are described and illustrated on pages 59 and 60, 

 Figs. 46, 47. 



Hyacinths can be propagated by leaf -cuttings. Strong leaves 

 should be taken in early spring and cut into two or three portions, 

 each portion being inserted about an inch in good sandy loam, and 

 given a temperature of about 75. In eight or ten weeks a bulblet 

 will form at the base of the cutting (see page 59). The lower leaves 

 give better results than the upper ones. These bulblets are then 

 treated in the same manner as bulbels. For Hyacinthus candicans, 

 see Galtonia, page 316. 



