The blue color of flowers among shrubs is not such a common occurrence. When it comes to large and lush ball-shaped clusters of flowers, there is nothing to choose from except hydrangeas.
Blue Hydrangeas are in considerable demand, which can even be compared to the demand for white Hydrangeas. Indeed, what could be more unusual and exciting than large blue balls on a background of green foliage?
In this article, I have created a list of the 15 best hydrangeas that bloom blue. Of course, their shades vary from variety to variety, as well as their care is a little different. You will learn about all of this in this article.
Read also: Which hydroponic system is best?
Endless Summer Original Hydrangea
Endless Summer Hydrangea is one of the best-known blue varieties because it tends to bloom repeatedly. If you plant it in your yard, you will enjoy its blooms all season long.
This variety grows 4 feet tall and wide, making it a dwarf blue hydrangea. The compact size is an important factor for many because there is not always room for larger plants.
For Endless Summer to have blue flowers you need to keep the soil slightly acidic. Mulching and aluminum sulfate does a good job of this. In alkaline soil, the color may change to purple-blue or blue with a pink tint. Also in such soil Endless Summer Hydrangea leaves can turn yellow.
Endless Summer grows fine from 4 to 9 USDA hardiness zones. You can prune this hydrangea almost any time as it blooms on new and old wood. Suitable for planting in both sun and semi-shade. Belongs to the mophead hydrangeas.
Nikko Blue Hydrangea
Nikko Blue is a great variety that blooms several times a year. It blooms before most blue hydrangeas. It starts blooming in the first half of June and lasts until the end of summer.
This hydrangea holds its blue color well, but in alkaline soils, it can change to lavender or slightly pink. For this reason, try to keep the pH below 6.0.
As for frost hardiness, Nikko Blue is recommended in zones 6-9. But if planted in a spot protected from winter winds, it will also survive in zone 5. But in this climate, it needs full sun, whereas, in zones 8-9, the partial sun is better.
This variety after 10 years has a maximum size of 6 feet tall and wide. This means it is a medium-sized hydrangea and can be grown in most types of gardens. In hot and dry climates, it needs more frequent watering than most hydrangeas.
Endless Summer Twist-n-Shout
Endless Summer Twist-n-Shout is a relatively new variety with blue flowers. It has a dwarf size, with a height and width usually not exceeding 3 feet. It needs almost no pruning and grows well in containers.
As for hardiness, this hydrangea can tolerate zone 4 and 5 frosts. In the south, it can be planted up to zone 9. But whichever climate you grow it in, Endless Summer Twist-n-Shout needs some shading. This means it needs six to eight hours of direct sun and the rest of the time it prefers to be in the shade. More than 12 hours of sunlight is too much for it and it can get burnt.
A small distinguishing feature of this variety is its darker leaves and dark red or burgundy stems, which gives it extra interest. It is also one of the first re-flowering lace-cap hydrangeas.
LA Dreamin Hydrangea
LA Dreamin is the best blue hydrangea for the sun. You can grow this variety in full sun without worrying that it will burn or lose color.
A unique feature of L.A. Dreamin Hydrangea is that it can grow clusters of flowers of different colors. You can see from pink to bright blue flower heads on one bush. But the more acidic your soil, the more blue flowers you will get.
Another strong point is its excellent frost and heat resistance. In the North, it can be grown in zones 5 and 6. In the south, it can be grown in zone 10, which is quite rare among hydrangeas.
L.A. Dreamin is 6 feet wide and 5 feet tall. Its shape is spherical and slightly flattened. It is a medium-sized hydrangea. Pruning can be used to control size as it blooms on old and new wood.
Nantucket Blue Hydrangea
Nantucket Blue Hydrangea can provide beautiful blue clusters of flowers from early summer that will last until the first frost. Most of the time it will have a light blue color, but it will turn pink if the soil is very alkaline.
This hydrangea is very hardy. It grows perfectly from zone 5 and up to zone 9 of hardiness. It can withstand both full sun and partial shade. Full shade is contraindicated, you must give it at least 6 hours of direct sun to get a generous flowering.
In terms of size, it is a fairly compact hydrangea. It rarely exceeds 5 feet in height and the same amount in width. It has a medium growth rate, so you will not have to cut it back often.
Endless Summer BloomStruck Hydrangea
Endless Summer BloomStruck Hydrangea is a dwarf hydrangea. It is less than 3 feet tall and up to 4 feet wide. This variety is an ideal candidate for potted cultivation or a small yard.
Its excellent hardiness (4-9 zones) allows it to be grown in northern states without risk of frost damage. It also tolerates the hot climates of the south well.
The color of this variety varies from blue to pink depending on soil type. It’s easy to control soil pH these days, as various sulfates can be found on the market that makes the soil acidic.
BloomStruck Hydrangea does not tolerate full sun all day long. So you need to place it in a place where there will be shade for part of the day.
The dark red stems are a characteristic feature of this variety. They contrast beautifully with the green foliage.
Tiny Tuff Stuff Hydrangea
Tiny Tuff Stuff Hydrangea is one of the tiniest blue hydrangeas. The height and width of this variety do not exceed 2 feet. The simple conclusion to be drawn from its size is that this hydrangea is best suited to growing in a container.
Another feature of Tiny Tuff Stuff is that the inflorescences have two types of flowers. One is fertile blue and the other is sterile and not fully open. The result is a very interesting effect called lace-cap. In the picture, you can clearly see what I am talking about.
Excellent hardiness makes it ideal for dwarf hydrangea lovers who live in zones 5 and 6. Tiny Tuff Stuff can grow in both full sun and partial shade. Thanks to its small size it does not need a lot of water.
Big Daddy Hydrangea
Big Daddy Hydrangea, as the name suggests, is a quite large variety. It reaches a height of 6 feet and a width of about the same. This cultivar also has large clusters of flowers and large leaves.
If you are not constrained by the size of your yard then choose this hydrangea. As a result, you will get huge ball-shaped clusters of blue flowers. The blue color will hold as long as the soil is acidic. If the soil is neutral, the color will change to purple.
Big Daddy Hydrangea’s frost tolerance is not the best. It can only be grown from zone 6 in the north to zone 9 in the south. You also need to hide it from direct sun for at least a few hours a day. That means you should never let this one get more than 8 to 9 hours of direct sunshine a day.
Due to its large size, Big Daddy needs extra watering during periods of drought. You also need to give this hydrangea enough fertilizer every season to get big flowers.
Tuff Stuff Ah-Ha Hydrangea
Tuff Stuff Ah-Ha Hydrangea is another amazing lace-cap hydrangea, but unlike Tiny Tuff Stuff, this one has sterile flowers not closed but partially open. As a result, the fertile flowers grow not on a green but a blue background. In fact, it gives a fanatical effect.
Also, its size is dwarfed, it is up to 2 feet tall and up to 3 feet wide. That said, the inflorescences are quite large, making it even more ornamental. To get the bluest color possible, the pH of the soil should be 5.5-5.7.
This hydrangea has a long flowering period, beginning in late spring and ending in late summer or even early fall.
Tuff Stuff Ah-Ha can grow in both partial and full sun. In zone 5, the more light it receives, the more abundant its blooms will be. It does not grow very fast. Flowering is possible on young and old stems.
Cityline Rio Bigleaf Hydrangea
Cityline Rio Hydrangea is of medium size. It can grow up to 2 feet tall and 3 feet wide. The growth rate is medium. Flower clusters and leaves are large.
You will not get a purely blue color from this hydrangea, even in acidic soil, it will have a purple hue to the flowers. However, it is more likely to be blue-purple or lavender than purple. In alkaline soil, it can change color to pink.
Cityline Rio has good frost resistance. It can be grown in zones 5-9. It needs additional fertilizing every year. If nutrients are lacking, it does not flower very abundantly. It is well tolerated in heavy and wet soils.
Everlasting Revolution Hydrangea
Everlasting Revolution Hydrangea is another dwarf variety. Its size slightly exceeds 2 feet in height and width. Compared to the larger hydrangeas, it grows more slowly. It does not need pruning and is best suited for container growing.
In acidic soil, this hydrangea will have light blue flowers. The edges of the petals have a white outline which gives a subtlety to the flowers. In alkaline soils, the color may change to pink and in neutral soils to purple.
Everlasting Revolution can grow on most of the territory of the USA. In the northern states, the stems sometimes die back to the ground during snowless winters and it does not always bloom on new wood.
Penny Mac Hydrangea
Penny Mac is not a very small but very beautiful hydrangea. It reaches a height of 5 feet and a width of 4 feet. The growth rate is medium to fast depending on soil nutrition and the amount of fertilizer.
Like most hydrangeas on this list, Penny Mac can grow in zones 5-9. It has a better tolerance to drought, while most hydrangeas need regular watering.
The color of the flower heads can be either light blue or pink. Adjusting the pH of the soil will help you achieve the desired result.
Does not tolerate planting in full sun, this is especially true in the south. The best place for this hydrangea is in partial shade.
Let’s Dance Rhythmic Blue Hydrangea
Let’s Dance Rhythmic Blue is a unique hydrangea. It can have part of the flower head colored blue and another part colored pink or purple. It can also be colored in three of these colors at the same time. To get vivid blue you need to add aluminum sulfate to the soil.
This hydrangea is ideal for compact gardens because it is usually no larger than 3 feet in height and width. It can also be grown in containers. It has good frost and heat tolerance.
The best place to plant Let’s Dance Rhythmic Blue is in the afternoon shade. Needs regular watering during periods of drought. For abundant flowering, you will need to give it extra fertilizer. Mulching the soil around the plant also gives good results.
Bloomables Double Down Hydrangea
Bloomables Double Down is a very interesting and wonderful hydrangea. Its first advantage is its double flowers. Each flower has one row of petals inside which there is another row of smaller ones. This gives a very beautiful and mesmerizing effect.
The second advantage is the very bright blue color. To make it hold up better, provide this hydrangea with acidic and well-drained soil.
Also, feed it repeatedly with mineral and organic fertilizers every year to keep it blooming.
Let’s Dance Blue Jangles Hydrangea
Another beautiful variety is Blue Jangles. Its flowers are blue, but sometimes a part of the inflorescence may be purple. This is especially common if your soil is neutral. In general you can say it is a purple-blue hydrangea.
As for size, it is a dwarf because it does not exceed 3 feet in height or width. As a result, it is easy to care for because no pruning or frequent watering is required.
Générale Vicomtesse de Vibraye Hydrangea
Générale Vicomtesse de Vibraye is a large hydrangea. It can reach 6 feet in height and 8 feet in width. You need to give it enough space to get good results. With proper care and proper conditions, this hydrangea blooms very profusely with huge flower heads.
The color is light blue in acidic soil and light pink in alkaline soil. The petals often have a white border. In addition, their edge is wavy which makes this variety even more interesting.
Can tolerate various types of soil. Also needs watering, especially in the first years after planting.
Générale Vicomtesse de Vibraye is one of the blue hydrangeas that can tolerate a lot of shade. There are examples of successful cultivation in a place with diffused sun all day long. Nevertheless, a few hours of direct sun are necessary for this hydrangea.
Blue Enchantress Hydrangea
Blue Enchantress is a beautiful hosta whose flowers are blue in color with a white middle. This hydrangea looks more elegant and ornate because of the admixture of white.
It is a repeat flowering variety, which means it can bloom for most of the growing season. It requires a lot of energy, so feed it twice a year.
Blue Enchantress is a vigorous variety that grows quickly. It is about 5 feet tall and wide, so it is a quite big blue hydrangea.
Early Blue Hydrangea
Early Blue is a dwarf hydrangea because it rarely exceeds 3 feet in both height and width. It can be grown in small gardens and even in containers.
The flowers are a very bright blue color. A slight pink tinge may appear in neutral soil. To prevent this from happening, keep the soil slightly acidic using aluminum sulfate.
The inflorescences are shaped like large balls. They abundantly cover the whole bush and look delightful against the dark green foliage.
Teller Blue Hydrangea
Teller Blue is a very beautiful hydrangea as it has lacecap inflorescences. Only some of the flowers are open while the rest of the flowers remain dormant. This gives a very beautiful lace cap effect.
The color is blue with a touch of lilac. The color may change slightly during the season, but the hydrangea is always beautiful.
This variety reaches up to 5 feet in height as well as width. It requires nutritious soil and regular watering to bloom abundantly.
Mathilda Gutges Hydrangea
And at the end of the list, I have a highlight for you – Mathilda Gutges. It is one of the bluest hydrangeas in existence at the time of this writing. Again, you have to have acidic soil to get the bluest blue. If the pH of the soil is at least 5.5, the flowers of this hydrangea will be deep blue; similar varieties are almost non-existent.
In the photo, you can see the real color that everyone can achieve in their garden. In alkaline soil, the color will of course change to pink, and sometimes the pink intensity is so high that the flowers turn crimson or even red.
As for cultivation, it is a fairly compact hydrangea, three feet across. It tolerates a variety of soils. Best planting location in the partial sun. With enough fertilizer blooms very abundantly.
How to grow blue hydrangeas?
Since most blue hydrangeas are bigleaf hydrangeas, the best place to plant them is in partial sun. Also, the soil should be nutritious and well-drained.
Next, we will talk in more detail about the growing conditions for this type of hydrangea. In fact, there are some features you need to take seriously in order to maintain the blue color of the flowers.
The best soil for blue hydrangeas
The first thing you need to take care of is the soil. The best substrate for blue hydrangeas is a slightly acidic and nutritious substrate.
To keep the hydrangea blue you need to provide it with acidic soil. Otherwise, the color can change to purple or even pink. Soil with a pH of less than 6.0 is acidic.
To keep the soil acidic, use aluminum sulfate. You can buy this product at many garden centers and it is specifically for hydrangeas. Use it strictly according to the manufacturer’s recommendations.
The second is that the soil should be nutritious and light. Since many hydrangeas are rebloomers, they need plenty of energy. To provide them with energy, add a few buckets of nutrient compost to the planting hole and mix it with the garden soil.
Should I deadhead blue hydrangea?
You should deadhead blue hydrangeas as soon as the flowers have faded. This is so that the new flowers have room to grow.
However, somewhere around mid-autumn, stop doing this. Hydrangeas need a resting time to recover and gain strength to bloom abundantly next year.
Cut back the flower heads slightly below where they are attached to the stem. Try not to damage the rest of the shrub or you may lose future flowers.
In general, only trim blue hydrangeas in early spring. Most of them bloom on both new and old wood. If you trim them in early spring, they will grow back to their full size by the time they bloom.
Blue hydrangeas grow best in partial sun. Again, this is because most of them belong to the Hydrangea macrophylla species. This species likes to stay in the shade during the hottest parts of the day.
But there are a lot of varieties that can withstand full sun. You will need to ask the seller what sun exposure would be best for the particular variety.
One thing is for sure, blue hydrangeas do not tolerate full shade. They need enough direct sunlight per day to bloom.
The best fertilizer for blue hydrangeas is a slow-release fertilizer for flowering plants. This fertilizer can have the N-P-K formula 12-4-8 or something similar. The main thing is to have nitrogen, phosphorus, and potassium, but not too much nitrogen compared to the other elements.
The best time to fertilize blue Hydrangea is early in the season, i.e. in spring. One application will be enough to make it flower abundantly once. But if your hydrangea is a rebloomer, fertilize it immediately after the first bloom and this will ensure a good second bloom.
Avoid fertilizing at the end of the season as this can cause young shoots to grow in the winter. Also, never over-fertilize and always follow the recommendations on the label.
Growing blue hydrangea in pots
Blue hydrangeas can even be grown in pots. However, it is imperative that they do not exceed three feet in size at maturity. In other words, dwarf blue hydrangeas are best suited for potted cultivation.
When choosing a pot, make sure that it has drainage holes at the bottom. If not, be sure to drill them.
Every year, repot hydrangeas in a new pot. Use a slightly larger container than the previous one.
The potting soil should be nutritious and light. Water the potted hydrangea when the soil is 1 to 2 inches dry.