2G EXPERIMENTS ON HYDRANGEA HORTENSIS. 



ARTICLE II. 



NOTICE OF EXPERIMENTS ON THE CULTIVATION OF HY- 

 DRANGEA HORTENSIS, IN CHANGING ITS FLOWERS FROM 

 THEIR ORDINARY ROSE COLOUR TO A BEAUTIFUL BLUE. 



BY MR. J. KURSSNER, LONDON. 



As the subject of transforming the flowers of Hydrangea Hortensis 

 from rose to blue is daily becoming of considerable interest, and, as 

 it well deserves, may be considered one of the most beautiful experi- 

 ments in horticulture, I beg to lay before you a statement of instances 

 by which it has been attained, and also of others in which the success 

 has been but partial or altogether unsuccessful, in hope that those 

 cultivators interested in this and similar experiments may have, as 

 conveniences may present, an opportunity of testing the efficacy of 

 the means now stated, and which, should they but offer additional 

 evidence, or lead to a development, of the true cause in producing 

 such a beautiful effect, will, I trust, be found of some value in aiding 

 the investigations of others, either with natural soils or chemical 

 applications. 



The first instance which came under my personal observation 

 occurred in the establishment of Mr. Hartman, at Minister, in Alsace, 

 France, where my friend the gardener was induced, in hope of 

 success, to try the effect of planting them in highly-pulverized char- 

 coal, which had lain unused for nearly twelve years, presenting the 

 appearance of black soil, and which, to his gratification, proved 

 invariably successful in producing flowers of a fine blue. In addition 

 to three parts of the charcoal was added one of common garden soil. 

 The plants were potted in the autumn ; and, being restricted to the 

 same composition whenever re-potted, each following season has been 

 attended with similar success. 



A second instance is published by an eminent lady horticulturist 

 in France, who possessed splendid specimens, which for fifteen years 

 were grown in different situations in one garden, without any differ- 

 ence in treatment, and during which time constantly produced flowers 

 of a rose colour ; but for the last five years have changed (without 

 any alteration in situation or treatment) to a decided blue; and in 

 the year 1841 have again varied, in some of the plants producing 

 blue and rose-coloured flowers on the same stem, and at one time; 

 thus offering a satisfactory answer to the supposition, that the separate 



