The present invention relates to the cultivation (preferably indoor) of Hydrangea species for increased production of phyllodulcin and the provision of a plant material, preferably a dried plant material, having an increased content of phyllodulcin.

Described herein are synergetic preparations for enhancing the water holding capacities of solid plant growth medium, consisting of a) ground zeolite, and b) powdered hypocalcic Montmorillonite expanse clay, and optionally c) granular expansive clay. Wherein the ratio of zeolite to Montmorillonite is between 1 to 0.25 and 1 to 30, and the ratio of powdered hypocalcic Montmorillonite expanse clay in the total amount of expansive clay is between 2 and 100%. Further optionally including components which aid product attractiveness, extend soil water retention, and assist plant and soil microbe growth.

Described herein are synergetic preparations for enhancing the water holding capacities of solid plant growth medium, consisting of a) ground zeolite, and b) powdered hypocalcic Montmorillonite expanse clay, and optionally c) granular expansive clay. Wherein the ratio of zeolite to Montmorillonite is between 1 to 0.25 and 1 to 30, and the ratio of powdered hypocalcic Montmorillonite expanse clay in the total amount of expansive clay is between 2 and 100%. Further optionally including components which aid product attractiveness, extend soil water retention, and assist plant and soil microbe growth.