There are several types of Hydrangea to consider. The Mop Heads or Hortensia above, the lace caps or other species. They are a rewarding group[ of plants to grow well but need the right conditions to excel.
Provide Suitable Growing Conditions
- All hydrangeas thrive in moist well drained fertile soil.
- Too wet and humid and you may get root rot and botrytis on foliage.
- Hydrangeas appreciate partial shade.
- Shallow chalky soil or light sandy acid soil may cause yellowing of leaves. To cure this water or foliar feed with Epsom salt (Mangenisum Sulphate).
- Hot dry conditions can encourage powdery mildew.
- Hydrangeas can be prone to insect attack from Aphids, Red Spider mite, Capsid bugs and even Vine Weevil.
- The main cause of non-flowering is pruning too hard and cutting off the buds. Just trim off the old heads in spring to the first fat buds.
- The failure of flowers to turn blue is caused by a shortage of trace elements of Aluminium. This is available in acid soils but not alkaline soils.
- Some species will change from pink to blue by using a proprietary preparation or colourant. This is unlikely to work when the soil is too alkaline.
- If you have a pink flower this can be enhanced by applying limestone or chalk during winter.
- White flowers remain white whatever you do. Some fade to a pink tinge.
Other Sources of information
Hydrangeas available from Thompson & Morgan
Amazon for Hydrangea books