96 



THE FAKM. 



garden immediately after the spring frosts (which would destroy the 

 flower-buds), the usual way is to put them under a hot-bed frame until 

 the shoots strike out from the tubers ; thus advanced in their growth, 

 they should be put toward the end of May into strong rich loam, deeply 

 and well pulverized. The herbaceous stem soon lengthens, and requires 

 a strong and high iron stake or frame to support it. 



The first winter white-frosts destroy the beauty and vegetation of the 

 plant, which should be cut down without delay. The tubers ^re then 

 to be dried in the open air a few days before they are put by ioto a 

 garret or dry store-room of any kind. 



The multiplication of the Dahlia by tubers is the most common and 

 convenient mode of culture. But grafting on the tubers is also em- 

 ployed. 



To effect this, a young shoot of the variety which is to be propagated, 

 is prepared at its lower extremity with the knife, in the usual wedge 

 manner, and inserted into a slit opened on one side of the tuber. This 

 is then put under glass into earth deep enough to cover the grafting- 

 point, and left there until the parts have united and the scion has 

 pushed out new leaves. The hand-glass over it shohld then be gradu- 

 ally removed. 



New sorts can also be grafted on the stem of a Dahlia in full growth, 

 just under the axil of a leaf, tying the bud and shoot to the stem with 

 a bit of woolen thread. 



By grafting thus in July, flowers of different colors may be produced 

 in the following autumn on the same stock. 



Dahlias are also raised from cuttings, stuck under glass, in June and 

 July. 



But a great number of varieties are obtained by impregnation of the 

 species, of which the crossings may be without end. 



By this mode the most brilliant and beautiful varieties may be gained 

 amidst a multitude of very inferior sorts. All is uncertainty in this 

 respect, but by the other modes any particular kinds can be multiplied 

 every season. 



GDAfTO, AS A MANURE. ITS COMPONENT PARTS, AND IMPORTANT USES IN 



THE GARDEN. 



« 



Guano, now estimated as one of the most highly-fertilizing manures, 

 appears to have been long known among the Peruvians, by whom it has 

 been used for ages. It is the excrementitious deposit of the numberless 

 sea-birds with which the islands from which it is procured abound, and 

 on which rain or humidity are equally unknown. By chemical analysis, 

 it is found to contain about one fourth part of uric acid in combination 

 with ammonia ; it is also found to contain oxalic acid in combination 

 with ammonia and potassa, and phosphates of ammonia, of lime, and of 

 potassa. 



Guano, thus rich in ammoniacal salts, acts particularly favorably on 

 vegetation. By abstracting the carbonic acid from the atmosphere, it 

 is the means by which the primary principles, as starch, mucus, etc., are 

 formed, of which the body of the plant is constituted. 



