Hydrangeas are beautiful plants native to myriad different regions and countries including; the Himalayan mountains, Indonesia, Asia, Japan, and the Americas.
Their flamboyant, fragrant and very pretty blooms make them a popular choice in all sizes of gardens.
So it is understandable that you would want an answer as to why, for example, is your Endless Summer Hydrangea not blooming, when you’ve gone to all the trouble of selecting a variety renowned for blooming from spring right through summer and on into autumn.
The name hydrangea is a combination of two Greek words — “hydor” meaning water and “angos”, a direct reference to their cup shaped seed pods but double apt as they are renowned for guzzling water.
This immediately offers a clue as to one possible answer when people ask why their hydrangeas won’t bloom; insufficient water!
However, there are several other possible reasons why a hydrangea won’t flower and different reasons for different types of hydrangea so first of all let’s help you identify which type of hydrangea you have.
Types of Hydrangeas
Out of the 200+ species of Hydrangeas, there are four noteworthy kinds that grow in American gardens.
Bigleaf Hydrangeas (Hydrangea Macrophylla)
Due to the fact that the blooms are regularly used as cut flowers, they are often referred to as Florist’s Hydrangeas. Hortensia and French Hydrangeas, are the most common type of hydrangeas, and are available in three different types — mountain, mophead and lacecap.
This species is distinct for its large flower heads that are typically available in three beautiful colors — blue, purple, and pink.
The color of these can be confusing, as the blooms will change color depending upon the soil conditions that they are planted in.
Smooth Hydrangeas (Hydrangea Arborescens)
Hydrangea Arborescens is available in several different varieties, and is noted for its beautiful flowers that appear first as tiny lime-green globes opening up into a round head of beautiful creamy white flowers set off by lush dark green leaves.
These spectacular flowers can grow as big as 10-inches and are often planted as hedges in colder climates as they withstand low temperatures very well.
Oak-leaf Hydrangeas (Hydrangea Quercifolia)
Not surprisingly, named after the shape of their leaves, Hydrangea Quercifolia is another hardy type of hydrangea suitable for colder temperatures and can be grown in sun or shade in moist soil.
They feature cone-shaped clusters of white flowers that in most cases fade to pink, and then to tan.
They are also the only Hydrangea with the added bonus of leaves that change color in the autumn, graduating from yellow through orange to a gorgeous deep red.
Climbing Hydrangeas (Hydrangea Petiolaris)
Native to America, these hydrangeas have a distinctly different habit compared to the other Hydrangeas as they are in fact a vine and suitable for training up walls, trees and even along the ground.
Their flower heads are flattish with fragrant white flowerets on the outer edges and smaller budlike flowers in the centre and can grow up to 5 inches in diameter.
In autumn the flowers turn a reddish-brown colour and are used effectively in dried flower arrangements. The textural peeling bark also offers an added attraction in winter.
Some Key Reasons For Hydrangeas Not Flowering
So now that you’ve had a bit of background to help identify your hydrangea lets look at the reasons why hydrangeas won’t bloom and in particular why your hydrangea doesn’t bloom.
Pruning at the Wrong Time of Year
Pruning at the wrong time of year is a trap that many hydrangea growers fall into and if you get it wrong then quite literally your hydrangea won’t bloom.
Early flowering hydrangeas flower on old wood and set their buds in the northern hemisphere from August onwards ready for flowering the following Spring, so if you prune them after August you will very likely have no flowers the following year.
Late flowering varieties flower on new wood which starts shooting in the spring so it is best to prune just before that in late winter/early spring.
There are a select few varieties which are ‘remontant’ meaning they will reform flower buds on a stem where the first buds have been incorrectly pruned, or perished due to early frost.
The reason they are able to do this is because they flower on both old and new wood.
Check which variety you have before pruning.
n.b. dead heading does not count as pruning, dead heading enables the plant to save energy it would otherwise have used for making seeds and enables it to rather use it for invigorating root and shoot growth ready for producing more blooms.
If there is an extra cold winter and you have a variety that is not very hardy then frost/freezing conditions could wipe out all of your blooms for the following spring.
Depending on the size of your bush and your dedication this can be avoided by keeping an eye on the weather forecast and if they are planted in the ground you might want to wrap the budding flower heads in burlap or a similar material (not plastic as they need to be able to breathe).
If you are growing your hydrangea in a pot then put them undercover in the greenhouse/shed/garage until the worst of the winter is over.
Check your plant hardiness.
Location of The Hydrangea Tree
If you have never seen your hydrangea bloom then it could well be that it is not planted in a location with the required lighting conditions, soil type or weather conditions and may never have bloomed.
Again, knowing your variety will help identify whether or not this is the problem.
Has The Hydrangea Flowered in the Past?
If your hydrangeas aren’t blooming but have previously flowered beautifully then it is worth checking if something has changed in its’ immediate surroundings.
Has a fence or wall been built that is now casting too much shade?
Likewise has a wall or building been knocked down causing your new hydrangea buds to be shrivelled by scorching sun.
Landscape changes can also affect the drainage, water supply and condition of the soil.
Animals moving into the area and chomping on the lovely tender new buds is also often a reason why you think your hydrangea won’t bloom, when in fact it had started to do so.
Check for tracks and newly nibbled stems.
Hydrangea Fertilization Problems
As we have indicated above, there are various reasons as to why a hydrangea doesn’t bloom but one of them is NOT due to UNDER fertilization.
If the problem is caused by fertilizer then it is far more likely to be the application of too much fertilizer, which can dry out the roots causing severe damage or even resulting in death.
Fertilizing at the wrong time of year can also be a reason why hydrangeas won’t bloom.
If the fertilizer is applied too close to the start of the plant preparing to go dormant then it could cause the plant to send out new shoots too early which then succumb to winter frosts.
Check the ideal fertilizing strategy for your particular variety and remember not to fertilize directly around the base of the plant, but rather around the drip line.