THE ASTER, 135 



and both tasks must be pursued assiduously, or the flowers 

 will be below exhibition mark. 



Well-grown plants will usually produce more flower- 

 heads than they can fully develop ; therefore it is a nice 

 point to thin them in good time. The beginner may 

 with advantage remove all the heads save the centre and 

 three side shoots, thus leaving only four heads of bloom 

 to each plant. As experience is acquired, the rule may be 

 varied, and it will be found that French asters require 

 to be thinned more severely than German, which may 

 in a good soil be allowed to carry half a dozen ; but they 

 should never be thinned down to one or two, because while 

 this spoils the appearance of the plants, it does not result 

 in the production of better blooms, for when asters are 

 grown beyond a certain degree of strength they are likely 

 to become coarse. 



In a hot dry season, asters are peculiarly liable to the 

 attacks of " red spider " or acarus, and " green fly " or 

 aphis. A precaution often adopted to prevent this con- 

 sists in covering the bed with a mulch of two or three 

 inches of half-rotten dung. This should be put on as 

 soon as the crown bud is visible, and should be followed by 

 regular and copious watering. The healthy and vigorous 

 growth that this treatment promotes is calculated to keep 

 insect foes at a distance, for the sickly plant is soonest 

 attacked by them. When the young plants are infested 

 by green fly it is safer to dust them with tobacco powder 

 than to use any kind of wash. As a rule, indeed, tobacco 

 powder is always to be preferred, because dry and clean 

 and easily washed off. 



The immense popularity of the aster accounts for the 

 number of varieties that are offered in the seed lists, for 



