174 Experiments on the Colours of the Hydrangea Hortensis. 



Plants sent to Covent Garden for some years, by Mr. 

 Smith of Dalston, and some which were sold by other Gar- 

 deners in the vicinity of London, were known to bear very 

 perfect blue flowers ; these plants were shifted in the winter 

 from the common compost in which they grew, into bog earth, 

 and the transition was successful in its operation. I accord- 

 ingly removed plants into pots filled with the bog earth of 

 Hampstead Heath ; but to my great mortification, they still 

 retained, when in flower, the original colour. I am, however, 

 assured, that by shifting the plants from loam or compost, 

 into the bog earth used in the nurseries round London, they 

 will blow blue ; and I hear that Mr. Smith still succeeds 

 with this practice. 



What I failed to effect by experiment, I at last obtained 

 by accident ; a Hydrangea, which I had turned out into a 

 particular border of the shrubbery at Kenwood, produced 

 blue flowers two years successively. The soil which caused 

 the plant thus to change, was a pure pale yellow loam, incli- 

 ning to a light bnck earth, such as is used for Pine-Apple 

 plants, and which is found in abundance on Hampstead Heath, 

 from whence I have since taken it for the same purpose, with 

 equal success ; and Mr. Morgan has informed me, that he 

 has always made his Hydrangeas produce blue flowers, by 

 planting them in similar loam, from a common in the neigh- 

 bourhood of North Mimms Place in Hertfordshire. I have 

 also lately learned, that, in gardens and shrubberies, where 

 the borders are formed of this sort of loam, the Hydrangeas, 

 which are turned out into them, always blow blue. 



Having thus attained my object, 1 continued to grow my 

 Hydrangeas, some with red, and some with blue flowers, 



