How To Look After Blue Hydrangeas. When trying to learn how to make blue hydrangeas with vinegar you will want to avoid this type of soil. If you add acidic organic mulch to your hydrangeas the soil will be more likely to remain moist and cool.
Give the hydrangea a thorough soaking at the base daily for the first week while the plant gets established. Adding coffee grounds to your soil will also help to get the beautiful deep blue color. You can also add additional aluminum sulfate to your soil throughout the growing season.
Caring for Hydrangeas 1 Keep the soil moist.
Water your plants at the base rather than on the leaves to help. Are your blue garden hydrangeas not staying blue even after adding aluminium sulphate. When trying to learn how to make blue hydrangeas with vinegar you will want to avoid this type of soil. And use rainwater if possible.