Hydrangeas are known for large clusters of flowers that are produced in summer when most other flowering plants have already wilted. Some hydrangea plants produce pink or blue flowers based on the pH of the soil. If your hydrangea fails to flower, the reason may be a deficiency in care or a mistake in cultural practices.
There are two types of flowering hydrangas. Some of these, such as Annabelle hydrangea, produce flowers on new growth each spring. Others, such as Mophead or Lacecap hydrangea, produce growth on 1-year-old wood. If the second type are pruned in spring, the 1-year-old wood has been removed. Although the plants will produce new growth, they will not produce flowers that year. Most hydrangea of the second type do not need to be pruned yearly. Cut Annabelle hydrangeas back to the ground to produce new blooms.
Spring weather can be unpredictable. Sometimes a late spring freeze will occur after several weeks of cold weather. When this happens, hydrangeas that have broken dormancy and produced buds may be damaged. The buds that have appeared may freeze. The weather does not have to be very cold for buds to freeze. You may not even notice that the plant has frozen until the blooms fail to appear.
If your plant has not bloomed after the first year you planted it, the hydrangea may not be hardy to your zone. Different hydrangea plants have different types of cold hardiness. A plant that is planted in a zone that it is not hardy to may continue to grow, but it may be damaged by harsh winter weather. As with late spring freezing temperatures, winter weather can damage hydrangea buds. If the plant is frozen to the ground, it may develop roots but the branches will appear dead. A hydrangea with this kind of damage may have leaves near the ground, but dead sticks instead of a canopy.
Too much shade
Hydrangeas will grow in both sun and partial shade, but the plants need a certain amount of sunlight in order to produce blossoms. A hydrangea that has no blossoms may be planted in full shade. Hydrangeas may also not bloom if they are given too much nitrogen fertiliser. Nitrogen will cause hydrangeas to produce foliage, but will not encourage blooms. Additionally, hydrangeas that receive too much water may not produce blossoms.