FLOWERING SHRUBS 53 



Now that the forcing of lilacs for cutting has reached such large 

 dimensions, we ought perhaps to allow ourselves a brief reference 

 to it. Forcing is best begun with the year, little being gained by an 

 earlier beginning. First, the plants should be subjected only to a 

 moderate temperature until they have become healthily active, at 

 which stage they may go into the forcing house with a temperature 

 of 70 to 80. When the truss expands and the flowers are about 

 to open, they will come a better colour and last longer if they are 

 removed to a house of 60, this slight hardening being all-round 

 beneficial. The following are good forcing varieties : Singles : 

 Charles X, lilac ; Marie Legraye, white ; S. de Louis Spathe, 

 purple ; C. B. Van Nez, blue. Doubles : Mad. C. Perier and Mad. 

 Lemoine, white ; Michael Buchner, purple ; Pres. Grevy, blue. 



VIBURNUM (GUELDER ROSE) 



Of all the Viburnums, and there are many, we have only to 

 do with the single and double forms of the variety " opulus," com- 

 monly known as the " guelder rose," or " the snowball." Some 

 of the others are very pretty and carry handsome bunches of berries 

 after blooming ; also, the greater part are admired for their autumn 

 colours ; but it is " the snowball " which is the really marketable 

 plant, simply because it is best known. 



The bloom of V. opulus is really very remarkable, for it resembles 

 a miniature close-packed spherical hydrangea. Coming sometimes 

 the size of a cricket ball, each truss is comprised of hundreds of 

 florets, which make a white fluffy ball. In the garden, planted by 

 itself, or with others in the shrubbery, it is very striking about the 

 time of Whitsun. Grown in pots and forced, it may be had in 

 abundance for Easter, and a great many are grown for this special 

 purpose. The double form, V. opulus sterile, is exceedingly hand- 

 some, and its flowers, when forced or even in the open, have all 

 the pure whiteness of snow. Cuttings may be taken from forced 

 plants in April and struck as greenhouse subjects, in heat ; or, as 

 is more usual, they are taken with other hard-wooded cuttings 

 in July and August and treated with them, as explained in 

 Chapter III. 



