Hydrangea coloring
Our tour continues, taking us into another section of the greenhouse. In this area, Bob has set aside a section for blue and purple Pink Verenas.
“The greenhouse is full of these black hoses, which supply water and feed to the plants. We also have these white hoses for coloured flowers. These contain water with added aluminium sulphate, which makes the root ball more acidic and changes the colour of the flower. Depending on the variety, the flower may end up light or dark blue or light or dark purple. We can also adjust the amount of aluminium sulphate we add, which will affect the intensity of the colour change.”