225 
' GARDENING AS A SCIENCE. 
I No. X. 
We recur to the subject of the Colouring of Flowers, as the few observations 
i which appeared in the Number of this Magazine of August last, upon the blue tint 
1 of Hydrangea hortensis, have excited some attention, and particularly in a quarter 
' which claims the earliest notice. In a word, we have been favoured with two 
communications of a nature so interesting, that we consider it just, not only to the 
I very able and practical cultivator who made them, but to the public, to lay before 
i our readers the substance of the letters, in order to induce experiments, which may 
! bring to issue a question that has been debated during a course of many years. 
Before we proceed further, it may be advisable to refer to the authority of 
Loudon on the introduction and general culture of Hydrangea, as we find them 
detailed in an early edition of his valuable Encyclop£edia of Gardening, page 864, 
No. 6476 ; for therein are embodied all that the best authorities had, till then, 
\ advanced upon the subject of change of tint. 
The native place of the Hydrangea is stated to be unknown — but it is commonly 
cultivated in the gardens of China and Japan, whence it was introduced to Kew 
by Sir J. Banks in 1790." Mr. Loudon thus alludes to what he considered 
varieties. Soon after it was introduced, some plants were found with blue 
flowers, which some supposed were produced by salt or saltpetre, and others by 
oxide of iron. The yellow-loam of Hampstead-heath, and some other places, and 
some sorts of peat-earth, are found to produce this effect ; but the cause is not yet 
ascertained. Dr. Daalen, of Antwerp, finds that turf-ashes, and still more effec- 
tually those of Norway-spruce, the wood generally used for fuel by him, applied to 
the roots of Hydrangea produced the blue colour of the petals (Short Tour, 122). 
According to Busch of Petersburgh, the Hydrangea will be turned blue by 
watering the young plant, the summer before, with alum-water. Our gray- 
coloured earth, under the black moor-earth, has the same effect, being combined 
with aluminous salt." (Horticultural Transactions, vol. iv., p. 568). 
Upon the foregoing data, most of the speculators in our modern Horticultural 
publications have rung their changes. Nothing new, in a word, has been adduced 
— and we may add, that a very early authority, Mr, Hedges, a reputed successful 
cultivator, observed If they (Hydrangeas) are expected to blow hlue^ they must 
be planted in pure yellow loam!' 
All these methods have been tried, and we remain just as we were ; blue 
flowers have been observed ; but they who experimented for themselves, have 
almost invariably met with disappointment. 
Here we arrive at the point at which we started, when we wrote the few 
remarks that appeared in August, and which elicited the observations we now 
refer to. 
VOL. X. — CXVIII. GG 
