1846.] The Laurel and the Plum. 331 



THE LAUREL AND THE PLUM. 



A writer (Mr. J. I. Thomas) in the first No. of the Horticul- 

 turist, p. 34, remarks that the laurel {^Kabnia latifolia) will not 

 flourish on a limestone soil, and that this has been proved by an 

 eminent horticulturist of this state. He goes on to state that this 

 plant will not flourish in soils containing carbonate of lime. Act- 

 ing on this belief, soil was procured from ravines which it was 

 supposed were free from this substance by filtration, which it 

 had been subjected to for centuries. Plants of the laurel being 

 placed in this earth were found to grow and flourish remark- 

 ably well 



In regard to this matter, though we have never found our 

 friend D. Thomas practically in error, yet in this case he is theo- 

 retically so. We were furnished with a specimen of this artifi- 

 cial soil, and found about the same proportion of carbonate of 

 lime as exists generally in western soils. 



The difficulty in cultivating the kalmias and rhododendrons 

 lies in the nature of the root, which spreads widely in a loose 

 soil abounding in vegetable matter. In transplanting, the roots 

 are usually injured, and are set in a soil too compact and too poor 

 in vegetable matter, and if exposed to the sun it invariably dies. 

 The difficulty in cultivating kalmias then is not so much the pre- 

 sence of carbonate of lime, as in the want of a proper quantity of 

 loose vegetable matter to absorb and retain sufficient water natu- 

 rally. A deeply shaded location is another requisite to success. 



It is a mistaken opinion too, that the soluble matters filter out 

 of soils when covered by forests. It is one of the beneficial influ- 

 ences of forest trees and wild shrubs, to maintain soluble matter 

 near the surface. 



Again, a correspondent of the Horticulturist, p. 132, (Mr. 

 John M. Ives) remarks, in speaking of the black wart on the 

 branches of the plum tree, that he has cut out at least fifty ex- 

 crescences, and has not been able to detect a single worm or in- 

 sect. And in another place farther on, "My opinion now is, that 

 it is caused by a diseased state of the sap," and illustrates the re- 

 mark by reference to the excrescences on the Azalea in the spring, 

 which he attributes to extravasation of sap. Now the probabili- 

 ty is, the writer has not looked for insects at the right season. 

 He will find the larva of an insect in the excrescence of the 

 plum in September. It is then mature or nearly so, and may al- 

 ways be found in the excrescence which has been formed during 

 the preceding summer. There is no question, then, as it regards 

 the cause of the black wart upon plum trees, neither is there as 

 it regards the juicy excrescence upon the Azalea; both result from 

 the perforation of insects. In the dry black excrescence the in- 



