One of the most popular ornamental flowering shrubs, hydrangeas are suited to a range of different planting schemes and styles. This versatility coupled with an easy going nature and prolific blooming habit has helped to make the plant one of the most popular in the garden.
These are popular ornamental shrubs.
But what do you do about a hydrangea not blooming?
A hydrangea not blooming can be disappointing. Luckily, there are a number of common reasons why this may happen and many are easily resolved. This guide is designed to take you through some of the most common causes and provide you with some easy to implement solutions.
1 Young Plants Failing to Flower
A newly planted hydrangea not blooming may not necessarily be a cause for concern. It could simply mean that the plant has yet to fully settle into its new position. Continue to care for the plant and, in time, it will start to thrive and flower.
Young plants in particular, such as those propagated from small leaf cuttings, can take a few years before they start to produce noticeable floral displays.
Young plants need time to grow and mature before flowering.
If you have never cared for these plants before, our How to Care for Hydrangea Guide is filled with useful information that will help you get the best out of your plants
2 Potted or Gift Plants
An increasingly popular gift, plants sold in a pot and gifted for Mothers Day or Easter are often replanted in the garden. While theseplants make a great gift, they rarely transplant well into the garden.
Gift plants typically grow in small pots and are wrapped in a decorative foil. If replanted into the garden, even with the best care possible, they often struggle to survive. This is largely because gift plants have been forced into early flowering. Gift plants are also often over fertilized.
All of this has a detrimental effect on the health of the plant, meaning that it is unlikely to thrive and repeat flower. In the case of gift plants, a gifted hydrangea not blooming is common. While you may have some success, the plant is unlikely to develop into a prolific bloomer.
Gift plants rarely flower.
3 Different Varieties Flower at Different Times
A hydrangea not blooming at the same time as other hydrangea plants may not be a sign that something is wrong. There are a number of different types of hydrangea and they don’t all flower at the same time.
Bigleaf (H. Macrophylla) is one of the most popular cultivars in North America. It includes varieties such as Mophead and Lacecap. Other commonly grown types include:
- Panicle (H. Paniculata)
- Mountain (H. Necrophilia subspecies serrata)
- Climbing (H. Petiolaris)
- Oakleaf (H. Quercifolia)
- Smooth (H. Arborescens)
Different varieties flower at different times.
Each variety begins blooming at a slightly different time so a hydrangea not blooming in your garden when other hydrangeas are covered in flowers may just be different types or cultivars.
The local climate also affects time. For example, in the South an Oakleaf cultivar flowers in early summer while in cooler Midwest or Northeast climates Oakleaf cultivars are later to bloom, flowering in mid or late summer.
4 Planting in the Wrong Climate
A hydrangea not blooming may be because it isn’t suited to your growing area. Different cultivars are hardy in different USDA Zones. For example, a Panicle type is far more cold tolerant than a Bigleaf cultivar. This means that Panicle types are better suited to planting and flowering in cooler conditions.
While less cold hardy types may survive the winter, if your chosen plant is a type that sets blooms on last year’s stems the buds may be killed off by winter frosts or cold temperatures.
Plants that are not suited to their growing conditions will struggle to develop buds and flowers.
A hydrangea not blooming simply may not be suited to its growing conditions. Do your research before purchasing any plant to ensure that it is suited to your climate. If you are unsure of your growing zone our guide to different planting zones not only explains the differences but highlights suitable plants for each area.
5 Plants Falling Victim to a Late Spring Frost
A hydrangea not blooming, even if it is suited to your growing zone, may have fallen victim to a late spring frost.
Unseasonably late spring frosts or exposure to unexpected cold temperatures can kill the buds causing them to fall from the stem. Exposure may also delay flowering or have a detrimental impact on your floral display.
Late spring frost damage can impact flowering.
Exposure to unseasonably cold weather or late spring frosts is particularly problematic for varieties that set flower buds on old wood such as H. Macrophylla.
Frost damaged buds are typically brown or black in color.
An easy way to prevent a hydrangea not blooming due to unexpected frosts is to monitor the weather forecast. If an unexpected late frost is forecast, cover the plants with a burlap wrap or horticultural fleece such as Frost Protection Bags.
Protection bags are permeable covers that protect your plants from the effects of the cold, night air. Simply remember to remove the protective covers the following morning, re-covering your plants every night for as long as necessary.
If late spring frosts are common in your area, you can also try allowing the spent blooms from the previous year to remain on the plant. Providing some winter attraction to otherwise bare gardens, the spent blooms also protect newly formed buds from frost.
6 Exposure to Too Much or Too Little Sunlight
A hydrangea not blooming may not be receiving the right amount of sunlight. These plants require at least 3 to 4 hours of direct sunlight each day for blooms to develop. The vast majority of cultivars prefer either early morning sunlight or dappled afternoon light.
Exposure to indirect light encourages lots of flowers to form.
If you have underplanted your floral shrubs beneath taller plants or trees, pruning away some of the limbs of the taller plant is an easy way to increase light levels around smaller plants. Alternatively, transplant the shrub to a sunnier spot.
Some people believe that transplanting is best done in the fall because it allows the plant to settle in its new position during the winter months ready to resume growing and flowering in the spring.
You can also transplant the plants in early spring. This gives them time to settle before the heat of summer arrives, enabling you to avoid transplant shock.
Positioning your plants in a place that receives lots of direct afternoon sun can also lead to a hydrangea not blooming. Too much sun can scorch the foliage.
It can also stress the plant, causing growth to slow and flowering to cease. This is because stressed or sickly plants try to conserve energy by producing fewer flowers. If your plant is struggling in too much sun, transplant it to a shadier location.
While some types such as H. Paniculata or the Panicle cultivar tolerate 6 or more hours of sunlight with ease. Other varieties prefer less sunlight, around 4 to 6 hours each day. A SONKIR 3-in-1 Light Tester enables you to monitor light levels in the garden as well as soil moisture content and soil pH levels.
7 Using the Wrong Fertilizer
A regular dose of fertilizer helps plants to grow and thrive. However, applying the incorrect type of fertilizer, or too much of a product, can be a cause of a hydrangea not blooming.
Fertilizers high in nitrogen can encourage lots of foliage to form. Excess foliage is often produced at the expense of flowers. A hydrangea not blooming may have been given too much nitrogen rich fertilizer. Even a balanced fertilizer, such as a 10-10-10 fertilizer, may contain too much nitrogen if your plants are already sitting in nitrogen rich soil.
The incorrect fertilizer can deter flowering at the expense of leaf production.
These floral shrubs love acidic soil. While you may assume that a fertilizer specifically for acidic loving plants is ideal, it can also have a high nitrogen content. Be careful when using such products.
Instead apply a fertilizer that is high in phosphorus. Bone meal can also be used. Either product promotes flowering. Fertilizers labeled as bloom boosters, such as Miracle-Gro Water Soluble Bloom Booster Flower Food, are ideal. For the best results, apply bloom booster fertilizers in early spring and again in midsummer.
A hydrangea not blooming in close proximity to your lawn may be struggling because your lawn fertilizer is increasing nitrogen levels in the soil. If you are uncertain, a soil test kit tells you how much nitrogen is present in your soil.
In addition to deterring flowering, too much nitrogen in the soil can also attract bugs and pests or cause plants to become leggy. Infestations are another potential cause of a hydrangea not blooming.
8 An Incorrect Watering Routine
A hydrangea not blooming may be suffering from drought stress or has been watered insufficiently. Remember, these plants like to be watered regularly and sit in well draining soil.
Water your plants regularly, this is particularly important during dry spells. These plants do best in soil that is consistently or evenly moist and well draining.
If the plants do not receive enough regular moisture they will become stressed and go into survival mode. This means that the plant focuses its energy on root and leaf production at the expense of flowering.
While flowering is attractive, it takes up a lot of the plant’s energy and is not necessary for the plant to survive. Therefore it is quickly sacrificed when plants enter survival mode.
Specimens growing in containers require more frequent watering than those in the ground.
If you are planting in sandy soil, work in organic material such as compost to improve moisture retention.
Mulching the soil around the base of the plants also helps the soil to retain moisture for longer.
While the plants require a regular drink of water, be careful not to overwater. Allowing plants to sit in soggy soil can cause issues such as root rot to develop. A soil moisture sensor is a useful tool if you struggle to know when to water your plants.
9 Pruning Incorrectly
Possibly the most common cause of a hydrangea not blooming is pruning the plant at the wrong time of year.
When and how you prune the plant depends on what type it is. Some varieties set buds and flowers on old wood, others, mainly Arborescens and Paniculata cultivars, set buds and blooms on new wood. Types that set bloom on old wood include:
Additionally, a few cultivars set floral buds on a combination of new and old wood.
Do your research before pruning to determine the best time to prune your plants. If you don’t know what variety is growing in your garden, observe the plants to see when and on what type of wood buds appear. This can help you to determine when to prune.
In general you should prune plants that set bud on new wood in the fall, as soon as flowering has finished for the year. Old wood types don’t usually need lots of pruning and are at their best if allowed to grow freely.
For example, Quercifolia cultivars can be left unpruned until April. At this stage you can lightly prune the plants, tidying them up and, if necessary, pruning to contain their spread. A truly low maintenance option, Anomalas require little more than deadheading the spent blooms, this is best done in late June.
A hydrangea not blooming but setting bud may be falling prey to the local wildlife.
One of the most destructive animals, deer can nibble away buds and new growth. They can also rip the foliage from the plant, giving the appearance of torn leaves. Some shrubs and plants are deer resistant, sadly the hydrangea is not one of these. Planting deer repelling plants alongside your floral shrubs may deter deer.
Deer can be destructive visitors to the garden.
If deer are a persistent problem in your area, you can try covering your plants in a homemade deer repellent solution. Another, easier way to protect the plants, is to cover them with a Natural Protector Jute Burlap Wrap during the winter months. to protect the plants.
Other smaller critters may also nibble the leaves and the buds. While this is frustrating they are nowhere near as destructive as deer.
Aphid infestations can be a common cause for a hydrangea not blooming.
While healthy specimens can withstand a few pests, more serious infestations can seriously harm your plant. Aphids, if allowed to live on a plant for an extended period, can suck the sap and life from a plant, stunting growth and deterring flowering.
Aphid infestations can cause great harm.
Regularly inspect your plants for signs of infestation. Small infestations can be washed from the leaves with a blast from a garden hose. Larger infestations may need to be treated with neem oil. Our How to Use Neem Oil for Plants guide explains how to safely apply the solution to any affected leaves.
Not only can weeds attract pests they can also harvest valuable moisture and nutrients from the soil. This can be another reason for a hydrangea not blooming. Use a weed puller to regularly weed the soil around your plants.
Mulching the soil around the base helps to deter weed growth.
Keeping the soil neat and tidy doesn’t just help your garden to look good, it also helps your plans to thrive. If you don’t have the time to dedicate to regularly weeding your garden, mulch the soil in early spring. This deters weed growth and also helps the soil retain moisture, further benefiting your plants.
Attractive floral shrubs, a hydrangea not blooming can be frustrating. Luckily many of the potential causes are easily solved meaning that you will soon be able to enjoy a magnificent floral display.