Method for colouring flowers of pot plants

A method for changing the natural colour of the flower or flowers of a pot plant, said method comprising the steps of:

• (i) providing a pot plant having one or more stems, one or more flowers and a root system surrounded by a potting medium for pot plants;
• (ii) providing a tubular injection device comprising a hollow tube having a wall with a thickness (d) in a radial direction of the hollow tube, a maximum size (D) in a radial direction of the hollow tube, a length (L) in a longitudinal direction of the hollow tube and two ends, wherein part of the wall of the hollow tube at one of the ends is removed so that an opening of the hollow tube at the end has the form of an open gutter, wherein the part of the wall of the hollow tube at the end that is removed extends from the end over a first distance (L1) in the longitudinal direction of the hollow tube;
• (iii) forcing the end of the hollow tube into the tissue of a stem of the pot plant over a second distance (L2) that is smaller than first distance (L1);
• (iv) providing colourant with a colour different from the natural colour of the one or more flowers to the hollow tube of the tubular injection device;
• (v) exposing the tissue of the stem to the colourant of step (iv) for a period of time sufficiently long to change the colour of the one or more flowers;
• and
• (vi) removing the tubular injection device from the stem of the pot plant, wherein no tissue is removed from the stem of the pot plant.