Tilotson's Journal of Horticulture 3: 54 (January 1868)
WHITE LILACS FOR WINTER
The white lilacs of the Paris flower-markets have long been famous, not only on account of their delicacy, but also the profusion in which they are produced. The following remarks from a correspondent in Paris will explain how they are obtained:—
"If there be one flower more than another indispensable to the Paris flower-market in winter and early spring, it is the white blossoms of the lilac. Large bunches of it may be seen in every flower-shop as early as the month of January, and it is always associated with the early violet and the forced rose. This lilac is the common kind, and yet it is produced perfectly white. The French florists have tried the white variety; but they do not like it: it pushes weakly, and then does not look of so pure a color as the ordinary kind, which, in its normal state, bears lilac-colored flowers. They force this common lilac in great quantities in pots, and to a greater extent planted out, as close as the plants can be stood, in pits, for the purpose of furnishing flowers for cutting.
"The plants that are intended for forcing are cut round with a spade in September, to induce them to form flower-buds freely; and they commence to force early in the autumn. They, at first, judiciously introduce them to a cool house: but, after a little while, they give them plenty of heat; and, when once they are fairly started, they get from 25° to nearly 40° C. (say from 77° to 100° Fahrenheit.) At the same time, abundant humidity is supplied, both at the root and by means of the syringe; but the chief point is, that, from the day the plants are put under glass, they are not allowed to receive a gleam of light, the glass being completely covered with the paillassons, which are the neat straw-mats so much used here for covering frames, pits, and all sorts of garden structures, in winter. Thus the lilac is made to push freely, and its white blooms are gathered before the leaves have had time to show themselves. The great degree of heat, - a degree which we never think of giving to any thing of the kind in England, -and the total shade to which they are subjected, effect the bleaching.
"The French commence to cut white lilacs about the end of October, and do so till lilacs bloom in the open ground." — W. R., in Florist.