Hydrangea HortensisGarden Hydrangea
It appears to be a point not yet fully determined, whether the present plant exhibits the appearances belonging to it in a state of nature, or those which are in a certain degree the effect of accident, or of art; in its fructification it certainly is not so completely barren as the Guilder Rose, Viburnum Opulus, cultivated in our gardens, since it has most of its parts perfect; yet as none of the authors who have seen it in China or Japan (where it is said not only to be much cultivated but indigenous) describe its fruit, we are inclined on that account to regard it, in a certain degree, as monstrous.
It will appear by the synonyms, that authors have entertained very different opinions as to what this plant really is; Jussieu following Commerson makes it an Hortensia, Thunberg a Viburnum, Loureiro, ridiculously enough, a Primula, and Dr. Smith an Hydrangea.
In the original description of the characters of the genus Hydrangea by Linnæus, there is no mention made of two different kinds of florets, as in the Viburnum, nor has any author that I am acquainted with described the Hydrangea arbor. as producing such; yet, to my great surprise, in a plant of this sort which flowered in my garden at Brompton in July 1797, three of the Cymæ, and three only, threw out each of them from their circumference a very different flower from those in the centre, smaller indeed, but very similar to the flowers of the Hydrang. hort. see Pl. 437. In 1788, Mr. Walter published his Fl. Carolin. in which he describes a second species of Hydrangea, which he calls radiata, having very distinctly, as in the Viburnum, two different kinds of florets in the same Cyma, this variation in the florets is added by him to the generic character: the similarity which exists between the flowers of Mr. Walter's Hydrangea radiata, and those of the present plant sufficiently justify Dr. Smith in making it an Hydrangea; the appearances observed by Loureiro on dissecting the germen, and our discovery of the existence of two different kinds of flowers in the Hydrangea arborescens, tend still more to confirm its propriety; we may add, that in the very habit of these several plants there exists a considerable similarity; still, however, it is only by ripe seed-vessels of the present plant, that this doubtful matter can be satisfactorily cleared up; but it will not follow, that if it be not an Hydrangea it must be a Viburnum.
This magnificent and highly ornamental plant, according to Dr. Smith, was introduced from China to the royal garden at Kew, by Sir Joseph Banks, Bart. in 1790; it was imported by Mr. Slater about the same time, with whom it is said to have first flowered in this country.
If room were allowed us, it would be superfluous to describe minutely a plant now so very common; suffice it to say, that from a strong perennial root, rise a number of half-shrubby, irregular, somewhat spongy stalks, strongly spotted when young with purple, from one to three feet high, terminated by large bunches of flowers, at first green, then rose-coloured, and finally green a second time; these are the most common changes to which they are liable: but it will sometimes happen that a plant which has produced red flowers one year, shall produce blue another, though growing in the same pot; this we saw happen in the year 1796 to a plant in the possession of the Countess of Upper Ossory, whose refined taste and superior judgment have in several instances contributed to render our works more acceptable to the public: the coloured changeable part of the flower is regarded as the calyx, in the centre of which is the corolla, containing the stamina, &c. all varying greatly in point of number; besides these, there are other flowers without any calyx, but the parts which they contain do not seem to be more perfect than those of the others, nor more productive of ripe fruit.
Since the introduction of this plant, trials have been made in regard to its hardiness, and it is found to survive mild winters if planted in very warm sheltered situations; but in others, both stalks and leaves are liable to be killed by slight frosts, though the roots are not; if persons are anxious to have it in the open border, the best mode will be to cut down the stems at the approach of winter, and cover over the root with rotten tan, or some light substance; in the spring fresh stalks will shoot forth, but it is more common to keep this plant during winter in a green-house or well secured frame; by artificial heat it may be brought to flower in April or May, without such, it begins to blossom about June, and continues in bloom till October; when successfully treated, it will acquire the height of three feet, and produce bunches of flowers supremely magnificent: such plants in pots are admirably adapted for decorating court-yards, balconies, &c. unless carefully cut in, it is apt to grow too large for the green-house, therefore it is proper to have a succession of young plants from cuttings, which strike very freely; this plant loves water, is indeed almost an aquatic, a rich soil, and plenty of pot room.