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 
