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PRUNING EVERGREENS. 



No. 576. — Sir, — Will you please let me know the best time to prune old evergreens, 

 and if there is any book published on this subject ? 



W. C. Searle, Clinton, Out. 



Reply by Prof. John Craig, Horticulturist, Central Experimental 

 Farm, Ottawa, On I. 



I do not gather from the question whether the pruning is to be applied to 

 evergreen plants singly, in windbreak form or as hedges. Then, again, it is 

 necessary to know what object the pruner has in view ; whether to increase the 

 vigor of the tree or to check its growth. Evergreens, meaning conifers, can 

 usually be kept in symmetrical form by simply nipping out the terminal bud of 

 any branch which is growing out of proportion with the others. Evergreen 

 hedges should be clipped during the first two weeks in June, and again about 

 three weeks later. 



In pruning evergreens it is necessary to cut back to a strong bud, thus 

 giving the limb a chance to start from the end bud so that it will not mar the 

 symmetry of the branch. One of the best books that I know of on the subject 

 of evergreens is that published by the Orange Judd Co. ; the author of it is 

 Josiah Hooper. 



Pear Leaf Mite— Rose Pierre Guillot. 



!*mt> Sir, — I have some young pear trees in full bearing, which showed symptoms 

 of blight two years ago ; last year the leaves were covered with black spots, also the fruit, 

 besides being much cracked. I send a sample of the leaves this year, and wish to know if 

 there is any remedy for it, or if the trees should be cut down to prevent it spreading ? Is 

 the rose "Pierre Guillot" able to stand the winter, or is it a house plant? An early 

 answer will oblige. Yours, 



J. H. Marshall, Woodlands, Stormont Co., Ont. 



Reply by Mr. John Craig, Experimental Farm, Ottawa. 



The pear leaves received are affected by an insect known to horticulturists 

 as the Pear Leaf mite, Phytoptus pyri. This has been treated by the Entomolo- 

 gist to the Farm, Mr. Fletcher, in the Annual Report for 1891, a copy of which 

 is mailed herewith. No satisfactory remedy has been discovered, but spraying 

 with kerosene emulsion early in June is thought to be the best. The rose, 

 Pierre Guillot, has not been tested in our rose grounds. It is a hybrid tea, and 

 therefore not likely to endure, without injury, our cold winters ; but with a fair 

 amount of protection, I think it could be wintered at Woodlands. It is said to 

 be as hardy as the tender hybrid perpetuals, such as Paul Neyron. 



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