390 



SCIENCE OF GARDENING. 



Part II. 



in spring, and of herbaceous plants after the season of their flowering, are generally^ to 

 remove from the parent plant the end of the succeeding autumn ; yet many sorts of 

 American trees require two years to complete their roots. On the other hand, some sorts 

 of roses and deciduous shrubs, if their present year's wood be laid down when about half 

 grown, or about the middle of August, it will produce roots, and be fit to separate the 

 succeeding autumn. 



Subsect. 3. Propagation by Inarching. 



2007. Inarching may be described as a sort of layering, by the common _ or slit 

 process, in which the talus or heel intended to throw out fibres, instead of being inserted 

 in the soil, is inserted in the wood, or between the wood and bark of another plant, so as 

 to incorporate with it. It evidently depends on the same general principles as layering ; 

 and all the difference is, that the granulated matter which exudes between the bark and 

 the wood of the talus or heel, instead of throwing out fibres, unites with the wood of the 

 stock or plant to which it is attached, forming a solid ligneous union, which, when the 

 layer or shoot is separated from the mother plant, supplies it with nourishment as the 

 fibres do the common layer. It is the most certain mode of propagation with plants 

 difficult to excite to a disposition for rooting ; and when all other modes fail, this, when 

 a proper description of stock or basis is to be found, is sure to succeed. Professor 

 Thouin (Cours Complet a" Agriculture, &c. art. Greffe) has enumerated thirty-seven 

 varieties of inarching ; but they may all be reduced to two, crown inarching, in which 

 the head of the stock is cut off (fig. 378. a), and side inarching (b and c), in which the 

 head of the stock is left on. With young hardy trees, the first mode is reckoned the 

 best, as the whole effort of the stock is thereby directed to the nourishment of the 

 inarched shoot ; the other is resorted to in propagating delicate trees, and for filling up 

 blanks in branches, and other purposes. 



2008. Preparatory measures. The stocks designed to be inarched, and the tree from 

 which the layer or shoot is to be bent or arched towards them, and put in or united, must 

 be placed if in pots, or planted if in the open soil, near together. Hardy trees of free- 

 growing kinds should have a circle of stocks planted round them every year in the same 

 circumference, every other one being inarched the one year, and when removed, their 

 place supplied by others, so that there will always be, by this practice, stocks of one year's 

 standing ready to receive the shoot. If the branches of the tree are too high for stocks 

 in the ground, they should be planted in pots, and elevated on posts or stands, or sup- 

 ported from the tree, &c. 



2009. Manipulation. Having made one of the most convenient branches or shoots 

 approach the stock, mark on the body of the shoot the part where it will most easily join 

 to the stock ; and in that part of each shoot pare away the bark and part of the wood two 

 or three inches in length, and in the same manner pare the stock in the proper place for 

 the junction of the shoot ; next make a slit upwards in that part of the branch or shoot, as 

 in layering, so as to form a heel, but more of a tongue shape than in layering, and make 

 a slit downward in the stock to admit it. Let the parts be then joined, slipping the 

 tono-ue of the shoot into the slit of the stock, making both join in an exact manner, and 

 tie them closely together with bass. Cover the whole afterwards with a due quantity of 

 tempered or grafting clay or moss. In hot-houses, care must be taken not to disturb the 

 pots containing the plants operated on. 



2010. Seasons for the operation. Inarching, like layering, is commonly performed in 



