MAINTENANCE 93 



change the nitrites back to nitrates. In regions rich in humus, grounc 

 water often contains organic as well as inorganic matter. Well water 

 may and often does contain plant food which is very valuable in the 

 form of nitrates or ammonia. 



Removing Seed Pods and General Care. Summer care of 

 perennials consists of removing seed stems and dead flowers. It is 

 extremely important to remove dead flowers at once, as formation of 

 seeds weakens a plant. And with many plants, such as the larkspur 

 and foxglove, new flowers also will be produced if the old flowers are 

 removed immediately after blooming. There is a considerable diff'er- 

 ence of opinion concerning the general maintenance of the larkspur. 

 Some persons think that the stock of this plant should be cut down to a 

 height of four inches to six inches immediately after flowering, other 

 persons feel that it should not be cut to a height of less than twelve 

 inches to fifteen inches. The author's personal experience has been 

 that if these plants are cut back immediately after flowering to a height 

 of four inches to six inches new shoots will be developed which will not 

 attain the height of the original plant but will develop excellent flowers 

 during the latter part of September. Support tall-growing plants with 

 neat stakes. In this class are asters, boltonias, and larkspurs. Do not 

 delay the staking until the plants have begun to fall over. Bare 

 spaces among plants in a border should be filled with annuals, if 

 necessary, as this will not only improve the general eff'ect but help 

 also to keep the ground shaded and cool, and provide bright spots of 

 colour after the first flush of bloom among the perennials is over. 

 Bare spaces may be filled by bringing in plants from a reserve garden 

 where they may be held in pots. New varieties of perennials and 

 biennials should be propagated and transplanted to the bed or border 

 to replace plants that run out or begin to fail. Seedlings will spring 

 up from many plants, such as anemones, marguerites, hollyhocks, and 

 campanulas, when seed pods are allowed to form. Such plants can be 

 used to fill up open spaces. 



Diseases of Perennials and Control. Perennials, taken as a 

 class, under fairly favourable conditions are not particularly susceptible 

 to disease. In general, when diseases attack perennial plants, the 

 safest thing to do is to throw them away. Aphis and minor insect 

 troubles may be easily controlled by spraying. 



