Hydrangeas prefer a fairly acidic soil that is rich in humus. If you are planting your hydrangeas in pots, then preferably use a special potting compost for hydrangeas. If you are planting your hydrangeas and rhododendrons in a border then it is important that you prepare the soil carefully beforehand. Enrich the soil in the plant hole with special hydrangea soil to ensure the right acidity for these ornamental plants and so that their roots can develop properly.
Alongside the right soil, hydrangeas also require the right fertilizer. As well as lots of potassium, they also need iron and magnesium. Iron ensures vibrant coloured flowers, while the magnesium is for luscious green foliage. Blue flowering hydrangeas tend to lose their colour over time. To return them to their original vibrant blue state, you can treat naturally blue hydrangeas.
After flowering, hydrangeas should be pruned back to 2/3 of their height and then covered with soil or leaf litter. This will help them through the winter; although the tops of the branches will freeze, this is no problem as these parts will be pruned off in early spring. In March, when the threat of heavy frosts has passed, the hydrangea can be pruned to the right height (down to two to three leaf bud pairs from the base of the stem).
Hydrangeas are beautiful plants, but they are also very susceptible to diseases and plagues, such as aphids. So it’s a relief to know that you can prevent these by using the right compost and plant food. After all, healthy plants are more resistant to diseases and plagues.