59 



BLUE HYDRANGEAS. 



There seems to be a general desire 

 among those persons who grow hy- 

 drangeas to possess those which bear 

 blue flowers. This cannot arise so 

 much from the greater beauty of the 

 blue ones, as they are for the most 

 part of a sickly colour, as because 

 they are comparatively rare. It would 

 perhaps not be uninteresting to exa- 

 mine the evidence which has been 

 submitted to the gardening public 

 during the last few years, in order to 

 try and ascertain, if possible, whether 

 there exists any definite mode of treat- 

 ment which will insure the production 

 of blue flowers. 



And here, at the very commence- 

 ment, a great difficulty arises ; for the 

 experiences of gardeners in different 

 parts of the country have been so 

 various, and the facts urged by some 

 are so diametrically opposed to those 

 put forward by others, that at first 

 sight it appears that the different 

 methods adopted for producing this 

 much-desired effect had nothing 

 whatever in common. The most 

 popular recipes for producing a blue 

 colour in the hydrangea appear to be 

 peat mixed with sand, loam, water 

 impregnated with iron, iron filings, or 

 iron scale from a blacksmith's forge 

 mixed with the earth, poor sand 

 below a pan of gravel, lime-water, 

 alum-water, marl, etc. It is to be 

 regretted that no persons well versed 

 in the science of chemistry have car- 

 ried on experiments through a conse- 

 cutive number of seasons, in order to 

 place the matter, if possible, beyond 

 the possibility of a doubt. However, 

 Professor E. Solly, thus reports to the 

 Horticultural Society, in 1842, upon 

 eome experiments made by him : — 



" Two perfectly similar plants of 

 the hydrangea were taken and placed 

 under the same general conditions 

 with respect to light, air, etc., and 

 watered with dilute solutions, the one 

 of carbonate of soda, the other of 

 muriatic acid, commencing with very 

 small quantities and gradually in- 

 creasing the doses. At the beginning 

 of the experiment it was difficult to 



distinguish the one from the other ; 

 they had both the same number of 

 leaves, were nearly of the saoie size, 

 and alike in colour and general vigour, 

 Hoth being remarkably healthy plants. 

 The solutions taken consisted of 1 

 drachm of concentrated muriatic acid 

 and 1 drachrn of carbonate of soda, 

 each dissolved in 50 drachms of 

 water. Of these, at first 1 drachm, 

 diluted with 2 ounces of water, was 

 given to each plant daily, but the dose 

 was gradually increased to 12 drachms 

 of each solution, so that in a month 

 the one had received nearly 5 

 drachms of concentrated muriatic 

 acid, and the other more than half 

 an ounce of carbonate of soda. 

 Under this mode of treatment 

 both plants continued to thrive and 

 flourish, and the blossoms were large 

 and perfect, those formed by the plant 

 treated with muriatic acid being 

 rather the most forward of the two ; 

 they were, however, both of the same 

 colour, nearly blue, although it wa3 

 believed that, had they been left un- 

 touched, the blossoms would have been 

 pink. It is evident that the acid 

 would have a tendency to render cer- 

 tain matters in the soil more soluble 

 than others, whilst the carbonate of 

 soda would have an opposite effect. 

 The acid would render lime, magnesia, 

 bases, and metallic oxides more solu- 

 ble, whilst the carbonate of soda 

 would facilitate the solution of silica, 

 acids, and organic substances in the 

 soil. The result of these experiments 

 is rather against those views which 

 have been formed respecting the blue 

 and red flowers of the hydrangea, in 

 which it is supposed that an absorp- 

 tion of iron or lime was essential to 

 the change." It is unfortunate that 

 there were not three plants in this 

 experiment, one of which was treated 

 with common water only ; for as the 

 effect of the two substances were so 

 different upon the soil, and yet the 

 colour of the flowers was precisely 

 similar, it seems but natural to sup- 

 pose that perhaps neither of them 

 had any effect upon the tint of the 

 D 2 



