The two most frequent causes of hydrangeas not blooming are improper pruning during the incorrect season and winter damage to the flower buds. On aged wood, hydrangea flower buds grow. The growing flower buds are removed during last year’s growth pruning, which prevents your hydrangeas from flowering.
The most typical causes of hydrangeas not blooming are:
- Hydrangeas’ springtime pruning removes the previous year’s growth as well as the budding flower buds.
- Frosts in the late spring might harm the newly budding flowers and stop them from blossoming.
- Numerous leaves flourish, but there are fewer blossoms as a result of too much nitrogen in the soil.
- To flower, hydrangeas need some sun or dappled light, and too much shadow will stop them from doing so.
- The hydrangea has not yet fully developed enough to blossom.
- The growth of flower buds can be harmed in the fall and spring by drought stress.
Continue reading to find out why your hydrangea isn’t blooming and how to fix the issue.
1. Pruning Can Prevent Flowering- Hydrangeas Bloom on Old Wood
Only the shoots from the previous year’s growth produce flowers on hydrangeas. The growth from which the blooms emerge is cut back if hydrangeas are pruned too severely or at the wrong time of year, which delays the hydrangea’s blooming until the following year.
In contrast to other shrubs (like roses), hydrangeas don’t require annual pruning and frequently flower best when left alone to grow.
Your hydrangea will typically grow a lot of beautiful green foliage in the spring without any flowers if you have drastically cut it back.
Once established, hydrangeas are highly hardy, and severe trimming usually has no effect other than to postpone blooming until the following year.
Instead of decreasing the shape of your hydrangea, focus on pruning any straggly or dying branches back to the base to encourage new growth that can support more flowers. Pruning hydrangeas should often just involve deadheading.
In order to stimulate more airflow and light on the developing blooms, it is best practice to clip away any dead growth back and spent flower heads to new healthy growth or the following flower buds in the spring.
As hydrangeas bloom from old wood, I must underline that heavy annual pruning is not essential and is likely to stop your hydrangea from blooming.
If your hydrangea needs to be pruned because it has grown too large for your garden, do it as soon as the flowers fade. This will give the hydrangea enough time for new growth to mature and become the plant’s flower-supporting growth the following year.
Watch this YouTube video for a wonderful visual guide on pruning and deadheading to promote flowers:
2. Winter Damage to Flower Buds
Frost damage to the flower buds in the spring is a common cause of hydrangeas not blossoming. Late Spring frosts injure the flower buds and prevent the hydrangea from flowering because the newly emerging flower buds are especially sensitive to a fast drop in temperature.
While hydrangeas can withstand freezing temperatures in the winter, the springtime new growth is more susceptible, therefore the most obvious indicator of frost damage is if the hydrangea flower buds and new growth look dark or black.
Because hydrangeas are better suited to living in woodlands where the protection of the forest canopy offers some protection from the effects of frost and bad weather, you should never plant hydrangeas in open or windy regions where they could be destroyed by the new growth that is still delicate.
Resisting the impulse to deadhead and instead leaving the old flower heads from the previous year on the plant is an excellent strategy to protect the developing bloom buds.
The old flower heads function as a reliable defense against frost and act as horticultural fleece to protect the developing buds from chilly temperatures.
This raises the possibility that the buds will survive any potential late frost and produce healthy hydrangea flowers.
Regarding this year’s flowers, it is best practice to use pruners to remove any frost-damaged growth because it does not recover.
By cutting back the damaged growth, you give flower buds that have developed further down the stem more light and a better chance of surviving a frost because they frequently receive some protection from the foliage.
After a frost, the damage to hydrangeas usually only affects the outermost growth, so if you’re patient, you might still see some blooms later in the summer on buds that are further down the stems rather than at the hydrangea’s outermost points.
(Read my post on how to save a hydrangea from wilting.)
3. Too Much Nitrogen Fertilizer (Reduce Fertilizer use)
For growth and flowering, all plants need the nutrients Nitrogen, Phosphorous, and Potassium (NPK). However, if the soil contains a lot of nitrogen, the hydrangea’s stems, leaves, and flower heads become sappy, weak, and droop with many fewer blooms on display.
Your hydrangea is more susceptible to pests and illnesses when it grows slowly and weakly as a result of excessive fertilizer use.
In order for hydrangea to produce flowers, the fertilizer balance must be perfect.
Personally, I advise using a fertilizer with a good mix of nutrients, such Miracle-Gro All-Purpose Granular Fertilizer for Hydrangeas, which has all the nutrients needed by hydrangeas for growth and blooming in the proper amounts.
The delayed release of nutrients from the granular formulation, which is a common issue with other types of fertilizers, helps to reduce any risk from using too much fertilizer or applying it in too high a concentration.
Reduce the amount of fertilizer you are currently using for your hydrangea if it has plenty of sappy leaf growth but few flowers, and keep an eye out for insect or disease infestations.
Provided the hydrangea is established, it may recover and produce flowers the following year if you use the proper fertilizer and according to the manufacturer’s directions. Hydrangeas are often tough plants that can survive a lot of abuse.
There isn’t much you can do to promote blooming in the interim once the fertilizer has been sprayed, so patience is needed.
It’s crucial to keep in mind that fertilizer used on lawns frequently dissolves in heavy rain and washes into garden borders where your hydrangea and other plants are placed.
If there has been significant run off following rainfall, plants in the adjacent borders frequently fail to bloom as a result of lawn fertilizer’s high nitrogen content.
(Hydrangeas typically appear to be drooping because of excessive fertilizer, but there are a few other possible causes for this. For a solution, see my article on why my hydrangea is drooping.
4. Not Enough Sunlight for Flowering
Morning sun, followed by afternoon shadow or dappled light, is when hydrangeas flower at their best. Hydrangeas grow a lot of foliage but no flowers if they spend the entire day in complete shade. The hydrangea is shielded from leaf scorch in the afternoon shadow and sunlight, respectively.
In order to provide them the energy for flowering, hydrangeas perform at their best in 4 to 6 hours of morning sun or dappled light beneath a tree canopy.
Finding a position with morning sun and afternoon shade or a region of dappled light under a tree canopy that allows some light in throughout the day to get the ideal mix of sun is best because harsh heat and high temperatures frequently induce drought stress and can scorch the leaves.
If your hydrangea isn’t blooming, think about whether the surrounding tree canopy has put too much shade on it and is preventing it from getting the sunlight it needs to grow.
In that situation, you can think about pruning back a few of the overhanging branches to help generate the dappled light conditions for a balance of sun and shade that will aid in promoting blossoms and preventing scorching of the delicate leaves.
Consider moving the hydrangea to a more sunny area of the garden if trimming back tree limbs or adding additional light is not practicable.
The optimum time to transplant hydrangeas is in the fall when the soil is still warm enough for the roots to take hold and the plants are not stressed by summer’s high temperatures, intense sunlight, and transplant shock.
5. Hydrangea not Mature Enough To Flower
Since they focus their energy on establishing their root system and adapting to their new environment rather than producing flowers, hydrangeas frequently do not flower in the first year after planting. The first year after planting or after a few years of growth in the soil is when hydrangeas often bloom the most.
A hydrangea that you buy from a garden center or nursery was probably grown under ideal conditions (such as controlled temperature, light, soil, fertilizer, and airflow) in a greenhouse before being put up for sale.
This indicates that, in contrast to the conditions in your yard, the hydrangea has evolved to grow in a highly particular and controlled set of environmental factors.
As a result, following planting, hydrangea may experience some transplant shock as it gets used to its new surroundings.
The hydrangea may not bloom in the first year after planting due to transplant shock, and is more likely to focus its efforts on growing roots in the new garden soil than than producing flowers.
The size and maturity of the plant must be taken into account because smaller, younger plants also use energy on growing, especially of the roots, as immediate survival is the major concern rather than the display of blooms.
The hydrangea should establish after about a year and grow into a larger, more mature plant, at which point it can afford to display flowers the following year as long as it has had time to adjust to its new surroundings and as long as it has good growing conditions (partial sun, moist, yet well draining soil, etc.).
In comparison to smaller plants, larger hydrangeas have a higher likelihood of flowering in their first year.
The hydrangea should bloom beautifully the next year if you give it about a year to mature and make sure it has all the conditions it needs to thrive.
Why are my hydrangea blossoms turning green? (Read my article.)
6. Not Enough Water Whilst the Flower Buds Develop
Natural woodland plants, hydrangeas thrive on soil rich in organic matter that retains moisture and has a porous, friable stricture that allows excess water to drain away rather than pool around the roots.
The hydrangea uses the leaves from the woodland floor as a natural mulch to help keep the soil moist around the roots and avoid drying out.
Your hydrangea will grow poorly and produce fewer blooms if it is in a small container, is in sandy soil that drains too rapidly, or hasn’t had enough moisture, especially in the spring when the flower buds are forming.
Because they can store more soil volume and moisture than smaller pots, which dry out too quickly for hydrangeas to endure, larger pots are preferable for hydrangea planting.
In order to recreate the ideal soil conditions and the perfect balance of drainage and constant moisture that hydrangeas need for flowering, hydrangeas should always be planted in garden borders that have been prepared with lots of organic matter (compost, leaf mold, or well-rotted manure) around the planting area.
Give your hydrangea a really thorough soak, preferably with a soaker hose so that the surrounding soil is evenly moistened, if there are drought-like circumstances.
Apply a 2 inch layer of mulch (leaf mold, compost, or well-rotted manure all work great) to the soil’s surface around your hydrangea to help retain moisture, improve the soil’s structure, and shield the soil from the sun’s direct exposure, which can cause the soil to dry out and the roots to become overheated, stressing the plant.
In order to foster healthy root growth, which boosts the hydrangea’s resistance to dry circumstances, water your hydrangeas as frequently as necessary to maintain the soil equally moist.
The hydrangea needs good, evenly moist soil that has been treated with organic matter, some sunlight, and healthy soil in order to produce blossoms the next year.
(Read my article to find out why my hydrangea is wilting.)
- The most frequent cause of hydrangeas not blooming is springtime pruning of the previous year’s growth, which destroys the developing flower buds. On ancient wood, hydrangeas grow and produce their greatest blooms when they are not clipped annually.
- Because hydrangea flower buds are just beginning to grow, a late Spring frost or particularly chilly winds might turn the new growth brown and prevent your hydrangea from blooming.
- If you use fertilizer too frequently or in too high a concentration, your hydrangeas won’t bloom because the soil has too much nitrogen. With too much nitrogen in the soil, hydrangeas tend to generate lots of lush green foliage growth rather than many flowers.
- In woodlands, hydrangeas naturally flourish in the filtered light of a forest canopy. In complete shade, hydrangeas tend not to blossom but still produce a lot of leaves. Hydrangeas flower best in regions of the garden with filtered light or in early sun followed by afternoon shade.
- Only when hydrangeas are mature plants that have been established for a number of years will they bloom to their full potential. When a hydrangea is young or has recently been transplanted, it focuses its efforts on developing its root system and does not produce flowers for around a year.
- To fully form, the hydrangea’s flower buds in development need continually moist soil. The hydrangeas will not exhibit flowers until the next year and the soil conditions are ideally moist if there is a time of drought or dry soil in the Spring or Fall when the buds are growing.
Why is my hydrangea not blooming this year?
If your hydrangea doesn’t bloom, the previous summer’s drought stress or insufficient watering may be to blame. Consider the weather from last summer to see whether this might be the reason. Make sure the soil is consistently moist yet well-drained to avoid this from happening again.
How do I get my hydrangea to bloom?
Why would a hydrangea not flower?
Inadequate pruning, bud damage from winter and/or early spring weather, location, and excessive fertilizer are the main causes of hydrangeas failing to bloom. There are hydrangea kinds that bloom on either fresh or old wood, or even both.