Culture of Hydrangea hortensis at Potsdam. 273 



Art. XII. On the Culture of the Hydrangea hortensis. as prac- 

 tised in the Potsdam Gardens. By M. G. A. Fintelmann. 



Sir, 



The finest hydrangeas which I saw in my late tour in Bri- 

 tain and Ireland, were in the Moncrief Garden, Perthshire ; 

 but still they were not so fine as we grow them here. 



The soil we prefer is what we call moor-erde, neither mo- 

 rass nor bog, but perhaps peat; because, in England, you 

 apply the term peat to very different soils. This soil is found 

 where rotted leaves and branches have lain for a century in a 

 shady valley, and formed there a moist place with black 

 earth, something like what you would call a bog, and on 

 which the native plants, for the greater part, cannot grow for 

 want of light. When this earth is collected, turned over, dried, 

 and reduced to powder, the colour is of a bluish black, the 

 consistence soft, spongy, and loose ; rather wet, but not very 

 much so. When we cannot get this soil, we take the mould 

 formed by the rotted peat or turf used here as fuel. 



Cuttings of the last year's shoots are put in the ground 

 early in the season and shaded, and they very soon strike root. 

 In the month of September we take them up, and pot them in, 

 small pots. The following spring we shift them into larger 

 ones, and cut them down to two or three eyes. They flower 

 in the following July, with a bunch or corymb for every bud 

 that is left. 



Every future spring, the preceding year's branches are 

 shortened to two eyes ; and when the plants become too large 

 for pots, they are taken out and separated. It is almost un- 

 necessary to observe that, in the growing season, the pots are 

 kept moist, and in the shade ; but it may be proper to state 

 that the most experienced practitioners prefer the shade of 

 trees to the shade of a wall, a hedge, or a building ; from 

 which, I think, we may conclude that the leaves of the 

 hydrangea consume a good deal of carbonic acid. 



To render the flowers of the hydrangea blue, we have no 

 fixed plan ; nor, after all that has been said on the subject, do 

 I believe the cause of the change known. We now and then 

 find a soil which, by accident, effects this ; and this soil, I have 

 always observed, contains a good deal of oxide of iron. We 

 have here a large hydrangea growing in this soil, in the open 

 ground, which is protected during winter with a wooden box. 

 In 1823 it was 5 ft. high, and 28 ft. in circumference, and bore 

 453 flowers. It has since died. 



Vol. V. — No. 20. t 



