156 BEAUTIFUL FLOWERS 



given when the pot rings hollow on being rapped, and never when 

 it sounds dull, whether it be twice a day or twice a month. 



Liquid manure will never be required by seedlings or cuttings, 

 or by young plants which have not filled their pots with roots. 

 It can only be used with benefit on plants that are established in 

 their pots, and have pushed roots right through the soil. Even 

 then it should never be given in strong doses. Where the pro- 

 prietary powder manures are being used, they may either be 

 sprinkled very thinly oveY the surface of the soil twice a week 

 and watered in, or made into liquid manure by stirring an ounce 

 in a gallon of water, and using twice a week. 



Insect Enemies. The best of plant cultivators are troubled 

 by insect enemies, although perhaps less severely than the worst. 

 Green-fly (aphides) is no respecter of plants. It will work more 

 havoc on a weak specimen than on a strong one, but it will make 

 a strong one gradually weaker, and may even kill it. It attacks 

 almost all kinds of plants. It will fasten on Roses, Cinerarias, 

 and Tulips with equal gusto. Have you a Mare*chal Niel on the 

 wall of your conservatory? Beware lest you find, when you cut 

 a bunch of flowers, that the stems are covered with a dense mass 

 of wriggling green insects, which cause you to throw down the 

 cluster, on the point of raising it to your nose for a long, ecstatic 

 sniff, in disgust. Green-fly moves to the attack swiftly. You may 

 be sure one day that a particular plant is free, but you can- 

 not be sure that it will not be overrun three days later. The 

 insect increases at a tremendous rate, and unless checked in an 

 early stage of its attack, speedily becomes master of the situation. 

 And green-fly is not the only pest. Mealy-bug is another plant 

 enemy, more offensive even than aphides. It clothes the stems 

 and foliage with a filthy white mass, making them disagreeable to 

 handle, as well as unhealthy. It does not spread so fast as green- 

 fly, but it is just as dangerous, because it is much more difficult 

 to destroy. It has a way of insidiously attacking roof plants, 



