Hydrangeas are eye-catching plants with flowers that range from blue to purple to lavender to pink. Some varieties also have white or green blooms. Thus, it can be disappointing if your hydrangea does not bloom at all.
Here are a few reasons why your Hydrangea is not flowering.
When you plant a hydrangea variety that only blooms on old wood, a rough winter can result in the plant not flowering the following year.
This is because the flower buds growing on old wood start to develop during the fall, but if the winter is below 5° Fahrenheit, it can kill the developing buds.
Some varieties can tolerate the cold, however, if you have a particularly harsh winter, you should provide protection to your plant from the cold.
You can protect hydrangeas from the cold winter by using a chicken-wire cage, or by wrapping the plant in burlap supported with stakes.
You can add straw or fallen leaves between the wrap or the cage and the plant for insulation.
Not enough water
Hydrangeas like plenty of water and consistently moist soil. If the soil is dry, or if you are not watering it enough, the plant may not bloom.
The soil needs to be moist but well-drained. Too much water can also be a problem while growing hydrangeas.
Hydrangeas can suffer if planted in hot climates in sandy or stony soil. It can cause the leaves of the plant to droop, as well as affect the formation of flower buds. It also limits the time of the flowers on your plant.
Some varieties need to be watered every other day in a hot climate. These plants need up to 2 inches of water every week.
If the leaves of your plant are wilting during the day, it could mean that they are not getting enough water.
If your hydrangeas are planted in soil with added organic matter, regular mulching around the plant, as well as plenty of shade to retain the water, it is an ideal condition for hydrangeas.
In this case, this plant doesn’t even need to be watered additionally in temperate climates.
Pruning a hydrangea can be a task, as the timing of the pruning depends on the variety of hydrangea you have planted.
Hydrangea falls into three main categories with regard to pruning. Some varieties bloom on old wood, some bloom on new wood, and some grow on both old and new wood.
Hydrangeas that grow on old wood should be pruned after they have finished flowering. Hydrangeas that grow on new wood should be pruned before they start blooming in spring, or when they become formant in the fall.
You can deadhead flowers after they have faded, or leave them be. If you decide to deadhead them, prune off the flower heads just above the first set of leaves.
Too much sunlight
Too much sun is not good for hydrangeas.
If the plant is exposed to direct sunlight for a longer time than necessary, the plant can get stressed. A stressed plant will focus on conserving energy, which is why it may stop flowering.
If your hydrangea is getting too much sunlight, it will show. The leaves of the plant can get scorched. The edges of the leaves will turn yellow, or brown.
Direct afternoon sun or full exposure to sunlight during the later parts of the day can often be too much for the hydrangea to handle.
Make sure that you transplant it somewhere where it will get partial shade so that it does not get burned.
Too much shade
Hydrangeas grow well in partial shade, but too much shade can be a problem for hydrangea blooms.
Although some varieties of hydrangea can flower in shade, they grow better in partial shade, for instance, if kept under dappled sunlight pouring through the canopy of trees. This is because this replicates the natural environment of the woodlands.
This issue can occur when the hydrangea is planted under trees that have not matured. It is hard to estimate how the tree will grow then. Sometimes, as the tree grows, it blocks more and more sunlight from reaching the hydrangeas.
Plants need sunlight in order to perform photosynthesis. Constant shade without any light at all will hinder the growth of the plant. It can cause the plant to grow spindly and with very few flowers.
Try to transplant your hydrangea to a sunnier location. Hydrangeas need a minimum of 3 to 4 hours of sunlight every day.
If that is not possible, you could try cutting back some of the tree limbs that are overgrown and covering the plant in complete shade.
According to information provided by New Jersey Agricultural Experiment Station at Rutgers University, all varieties of hydrangeas are often damaged by deer.
This means that if there are hungry deer around your area, they would prefer hydrangea.
The deer might eat buds that grow in old wood during the fall, winter, or spring. If the hydrangea variety that you have only grown on old wood, you might not get any blooms the following season.
You need to identify if it is indeed a deer that is harming your plants. Deer rip the leaves off the plant, so there will be signs like jagged edges and torn stems.
They prefer to eat the young green growth, buds, and leaves and avoid the stems, branches, and brown wood.
The easiest solution is to keep the deer out of your garden. You can do so by constructing a barrier, like a fence around your garden so that it keeps the deer away.
Another thing you can do is wrap the plants in burlap. This will not only keep them safe from deer, but also from the extreme cold, which is another reason why hydrangeas don’t bloom.
Potted gift hydrangea
If you are trying to replant a hydrangea that has been sold as gifts in tiny containers or pots covered in decorative foils, there is a good chance that it won’t bloom. It might not even survive for a long time.
Such plants have been forced to bloom early by growing them in such conditions and providing them with too much fertilizer. There is also a good probability that the hydrangea is not suitable for your zone.
There are a lot of different varieties of hydrangeas, and they are different in levels of hardiness. The bigleaf hydrangea is the least hardy, while the panicle hydrangea is the most tolerant to cold.
If you have planted a hydrangea and it is not blooming in that location, it is possible that it is not compatible with the hardiness zone of that location.
The root system of such plants might survive the cold, but the buds can be killed due to the extreme cold, which would mean that the plant would have no blooms the following season.
When a plant is provided with too much nitrogen, the plant puts most of its energy into growing the foliage. While doing so, the flowers are ignored.
Nitrogen is one of the primary nutrients necessary for plants to survive. They need it for new growth as well as to support the existing foliage.
Another important nutrient for plants is phosphorous, which helps in the development of seeds, roots, fruits, and flowers.
When the plant is provided excess nitrogen and less phosphorous, it is possible that the plant may not flower at all and instead grow larger leaves.
Do a soil test to figure out if it is excess nitrogen that is the cause for your hydrangeas not blooming.
Then, you can use a slow-release fertilizer that has more phosphorous than nitrogen.
To reduce the amount of nitrogen in the soil, you can try mulching the soil with sawdust or wood chips, or by planting plants that like nitrogen, such as cabbage or corn, nearby.
Newly planted hydrangea or transplant shock
If you have a young plant that you have recently planted, or if you have just transplanted a plant, it can take up to a year for the plant to become established and start flowering.
However, some plants start blooming in the first year itself without any difficulty.
This can happen especially when plants are grown in optimally controlled environments and then moved to a place where there is a contrast in the temperature, light, moisture, and soil conditions.
Young or recently planted hydrangeas can take time to adjust to the new conditions before they can start flowering.
This is because at first, they focus their energy on establishing new roots and getting accustomed to the new environment.
This is not something to worry about. Young plants or newly transplanted plants will take time to bloom. You only need to be patient and grow them in suitable conditions.
This means that the plant should be planted in partial shade. The soil in which it has been planted needs to be amended with a good amount of compost.
During the first year, the hydrangea should be watered regularly and often.
Pests and other diseases
Hydrangeas do not usually attract any pests or insects. However, if the plants around the hydrangea are prone to pest infestation, then it can become a problem for the plant.
Hydrangeas are also susceptible to fungal diseases like fungal leaf spots, powdery mildew, and rust.
Bud rot or botrytis is another disease that can affect potted hydrangeas. In this disease, the buds and flowers get covered with a grey mould and eventually die.
Look out for pests like aphids and beetles to check if they are damaging the plant. If you see any pests, remove them by hand and then spray an organic pest repellent on the plant.
To keep your hydrangeas safe from fungal diseases, try to water the plant in the morning so that it has time to evaporate. Also, make sure that the leaves do not remain wet.
Lack of space
If you have planted your hydrangeas in a crowded place, they might not bloom. Hydrangeas require space to grow and flourish.
If the hydrangeas are planted too close to each other or other plants, they will start to compete for the nutrients in the soil. This, as a result, will stunt their growth and prevent them from blooming as they should.
If lack of space is a problem, you might want to consider uprooting the plant and transplanting it to a location where there is a lot of space for the hydrangea to grow.