Transactions of the Horticultural Society of London, Volume 2: 153-155 (1818)

XXXIX. On the Cultivation of Lobelia Fulgens, in Belgium.
Jean Baptiste Van Mons, M.D., of Brussels.
Read March 7, 1815.

This plant, which was introduced into Europe by Baron HUMBOLT, one of the most learned naturalists who ever travelled, was sold in Belgium, only three years ago, for three and four gilders, and in Germany for five dollars; yet it is now so common in our flower markets, that it sells only for a shilling: so simple is its culture, and so easy is it to be increased. This is done by slips and cuttings: it also pushes suckers from the root, and each of these separated becomes one, two, or three plants. The stem also may be divided into as many pieces as there are leaves, and these pricked into a shady border, will each soon become a plant with roots; and the base of the stem, taken up before the frost, is surrounded with two or three circles of roots, as well as an infinite number of rudiments of buds, which finally develop themselves, strike fresh roots, and may be separated about Midsummer. A very strong plant, if not suffered to flower, may be multiplied ad infinitum. The Lobelia Fulgens succeeds perfectly, all the year, in the open air, and I am not even sure, that it is necessary to cover it with fallen leaves of trees, during severe frost; it will also accommodate itself to every soil, but multiplies more in a strong ground, which proves that it enjoys there less health: for a plant often makes great efforts for re-production, previous to its death. We have tried to vary this beautiful plant, by raising it from seed, in order either to acquire double flowers, or to change its colour; but our trials have not been attended with success. We have, however, produced a dwarf variety, the flower of which is more shining; the flowers are likewise nearer each other, and the foliage shorter and thicker in proportion. The Lobelia Cardinalis has already produced a permanent dwarf variety, but which is more liable to perish. There is also another variety of the Fulgens, of a different colour, namely a pale rose-coloured one, similar to that of the Cardinalis. This want of success has nothing surprising in it, the first propagation by seed being still too near nature to produce a variation. This mode of re-production must not therefore be given up, but repeated; the seed should always be taken from the last plants that have been separated from the original exotic. In thus departing from nature, the plant rather yields to art, and falls into monstrosity, which, in artificial gardening, is often the perfection sought for. A plant, transported from its native soil into a climate, where it does not grow spontaneously, when repeatedly propagated by seed, often degenerates, changes its colour, and becomes double. This is the principle of varying plants. It is impossible that a plant, which is so easily multiplied by slips, should not vary, when propagated by seed. A plant once degenerated, that is to say, once sown in a soil which is not natural to it, does not come back by seed to the form it originally had in its native country. Thence the continual variations of species, even in those climates where they grow in the open air. The plants spontaneously growing are distinguished from those that are sown, by the absence of all cotyledons about the young shoots.

* I obtained a few perfect capsules last summer, by fecundating the stigma, and taking off all the suckers as they sprang up.—Secr.

The slips of the Fulgens flower in the first year, but if they are neglected, and suffered to grow into tufts, they are two years before they flower. The plants raised from seed bear flowers in the second year. The seed should be sown, as soon as it is ripe, in earthen pans; the earth should be moistened, and after it has imbibed the water, the seed must be spread over it without being covered. The pans should be sheltered from the frost, and the young plants may be transplanted in April and May. Very few of them remain, more than the second year, without flowering. A little seed is ripened here, at Brussels, when the season is hot, and especially from those plants which flower earliest.* The moment that vegetation stops in the flowering stem, it should be cut off, and suffered to dry. The seed is so like dust, that it might be mistaken for it, and be thrown away. Mr. WITZTHUM, assistant in our botanic garden, has particularly attended to the cultivation of this plant. The Lobelia Cardinalis, which perishes so frequently in sandy soils, becomes strong, and multiplies without any care, in a clay ground; but it flowers in all its magnificence only in the former soil, and is, in this respect, conformable to the habits of the double varieties of Hesperis Matronalis.