Dyeing is especially used for the red Xeranthemum annuum fl. pl., red asters, and all kinds of ornamental grasses. Mix 10 parts fresh water with 1 of good nitric acid, plunge the flowers in, shake off the liquid, and hang them up to dry. In this way, Xeranthemums, which should be cut when entirely open, will acquire a beautiful bright red tint; while grasses only become a little pale red on the tops, but will keep afterwards for many years, and may, if needed, be coloured otherwise at any time. Asters generally, when treated in this way, are not so fine as if dried in sand, or smoked with brimstone. To colour flowers and grasses blue, violet, red, scarlet, and orange, use the different kinds of aniline: for yellow, use picric acid, and for bright scarlet, use borax. The aniline dye should be dissolved in alcohol before it is fit for use, in which condition it should be kept in well-closed bottles until it is required. It may also be purchased in a dissolved condition of any respectable chemist. To colour by means of aniline, take a porcelain, or any other well-glazed vessel, pour in some boiling water, and add as much dissolved aniline as will nicely colour the water. According to the quantity of aniline used, the colour of the flowers will become more or less bright.
After the water has cooled a little, plunge in the flowers or grasses, and keep them in it till they are nicely coloured; then rinse in cold water, snake off the liquid, and- hang them up in the open air to dry. To obtain a fine blue, take aniline bleu de lian, boil the colour with the water for 5 minutes, and then add a few drops of sulphuric acid before using. For violet, use 1 part aniline violet and 1 of aniline bleu de lian; for red, aniline fuchsin; for scarlet, 1 part aniline fuchsin and 1 of aniline violet; for orange, aniline d'orange; foi lemon colour, picric acid, which should be dissolved in boiling water, and then thinned with a little warm water. Dip in the flowers, but do not drain off the liquid. All kinds of ornamental grasses can be thus coloured (especially Stipa pennata and Ammo-bium alatum), white Xeranthemums, and most other everlasting flowers, Immortelles, however, as well as the other kinds of Helichrysuins, must be treated differently; their natural yellow colour must first be extracted by dipping them in boiling soap-water, made with Italian soap, and afterwards dried in an airy, shady place. The flowers generally become closed when thus treated, and should be placed near an oven, and subjected to the influence of a dry heat, when they will soon reopen.
This is very important, if they are intended to be coloured; if not, they will remain fine pure white immortelles. Most immortelles, however, are coloured bright scarlet by means of borax, which gives a beautiful colour; but it does not keep well, and becomes gradually paler. For this purpose, dissolve as much borax in boiling water as will colour it nicely; when cool, dip the flowers, but do not allow them to remain in after they have taken the colour; if kept in too long, they will not again open their flowers. The chief point in every mode of colouring immortelles is to place them first in a dry, warm atmosphere, where they will open their flowers well; and, after colouring, they should again be exposed to heat, by which means they will nearly always reopen them. Very nice-looking immortelles are also produced by colouring only the centre of each flower scarlet, which is done very rapidly with borax, by means of a small pencil or a thin wooden splinter, dipped into the colour and afterwards applied to the centre. This is generally done by little children in those establishments in Germany and France which supply the trade with everlasting flowers.
Finally, a very cheap and a very good recipe to colour ornamental grass and moss a beautiful green: - If a dark green is required, take 2 oz. boiling water, 1 oz. alum, and 1/2 oz. dissolved indigo carmine; plunge the moss or grass into the mixture, shake off the liquid, and dry in an airy, shady place. In the winter, however, they should be dried by means of fire-heat. If a light green is required, add to the above mixture more or less picric acid, according as a more or less light shade is required. (Eng. Mech.)