How To Care For Nikko Blue Hydrangea?

Do you have a Nikko Blue Hydrangea in your garden?

Like most people, you probably bought your Nikko Blue Hydrangea because of its beautiful blue flowers. And if you’re lucky, your plant is thriving and producing plenty of blooms. But if it’s not doing so well, don’t worry – we can help.

In this article, we’ll share tips on caring for your Nikko Blue Hydrangea so that it will bloom all season abundantly long. We’ll also show you how to prune it correctly to stay healthy and look great. So please read on for all the information you need to keep your Nikko Blue Hydrangea looking its best.

There are several kinds of Hydrangea, all of which are appealing and plentiful in blooms. Still, one particular variety comes to mind when people talk about the plant: Nikko blue hydrangea. 

The Nikko blue hydrangea, part of the Hydrangea macrophylla species, is a bigleaf hydrangea considered dense clusters of tiny flowers on tall stems.

Hydrangea bushes are deciduous flowering shrubs in the mophead (hortensia) family. Because they produce significant clusters of petals, they are also known as mopheads. 

On the other hand, the “lace-cap” type of Hydrangea has a flatter flower head with the sepals aligned nearer to the perimeter and surrounding the tiny, fertile flowers in the middle.

Hydrangea macrophylla, including the Nikko blue hydrangea, is native to Japan and should be planted in the fall or early spring. They will rapidly develop and may reach a height of up to 24 inches each year.

Follow the instructions in this article to help your Nikko Blue Hydrangea thrive!

Choose the Right Kind of Hydrangea

Hydrangeas are one of the most famous gardener shrubs, and it’s easy to see why. Hydrangeas add instant drama to any landscape with their large, showy blooms. But did you know that not all Hydrangeas are created equal? 

Only the flowers of bigleaf Hydrangea (Hydrangea macrophylla) can change color. Other types such as oakleaf Hydrangeas or smooth Hydrangeas such as ‘Annabelle’ only bloom in white or cream. 

These plants are just as complete and beautiful, but if your goal is blue Hydrangeas, make sure you’re planting varieties that can turn the shade you want.

Plant in the Right Location

Hydrangeas are a popular garden choice due to their large, showy flowers. But before you add them to your landscape, it’s essential to pick the correct location. 

Hydrangeas prefer partial sun to partial shade and well-drained soils. They also need a fair amount of moisture, so avoid planting them in drought-prone areas. With a bit of planning, you can ensure that your hydrangeas will thrive in your garden.

Choose Blue Varieties

Hydrangeas are one of the most popular landscaping shrubs due to their large, showy flowers. While the flower color of most hydrangeas is affected by the soil’s pH, some varieties are bred to be blue regardless of the soil conditions. 

Nikko Blue, Endless Summer The Original, ‘Penny Mac,’ ‘Blauer Prinz,’ and Endless Summer Twist-n-Shout are all examples of blue-flowering hydrangeas. 

If you’re looking for a blue hydrangea and the plants at your local nursery aren’t in flower, look for a variety with blue flowers in the photo on the plant tag. You’re sure to find the perfect one for your landscape with so wide beautiful blue varieties.

Pick the Flower Hue You Want

Hydrangeas are one of the most popular flowers, known for their large blooms and wide range of colors. While the flowers can be found in shades of pink, blue, and purple, the actual color of the bloom is determined by the pH level of the soil in which the plant is grown. 

The hydrangeas need to be grown in acidic soil with a pH of 5.5 or lower for actual blue flowers. For pink flowers, the plants need neutral to alkaline soils (pH 6.5 and higher).

For purple blooms (or a mix of blue and pink flowers on the same plant), the pH of the soil must be between pH 5.5 and 6.5. Your soil test results will help you figure out what to do next. With a bit of knowledge and effort, you can grow Hydrangeas that are exactly the color you want.

Adjust the Soil pH

Because most garden soils are neutral, you’ll need to increase the acidity 

in order to turn them blue. You have a number of options. Sulfur and sulfate are two organic acidifiers. There are also soil additives available that are specifically designed for hydrangeas.

To make your hydrangeas more colorful, appeal more vibrant, and produce better flowers, use an acid-based fertilizer such as Miracle-Gro Acid-Loving Plants Food. This product will help you maintain the ideal soil conditions for blue blooms.

While hydrangeas can tolerate a range of soil conditions, they tend to produce the best blooms in soil with a pH of 6.0 to 6.5. If your soil is too alkaline or acidic, it can cause the flowers to fade or change color. You can use a soil test kit to measure the pH of your soil and adjust accordingly.

Add lime to raise the pH or sulfur to lower it. With a little effort, you can ensure that your hydrangeas always look their best.

Hydrangeas are lovely, old-fashioned flowers that have been gracing gardens for centuries. But unlike other plants, they can be a bit finicky when it comes to their soil pH.

Hydrangeas prefer slightly acidic soil with a pH between 6.0 and 6.5. If your soil is too alkaline, the flowers will be less vibrant and may even turn green. On the other hand, if your soil is too acidic, the flowers will be stunted and the plant will be more susceptible to disease.

Luckily, there are a few simple things you can do to adjust the pH of your soil and ensure that your hydrangeas thrive.

To raise the pH of your soil (make it more alkaline), you can add powdered garden lime or dolomitic limestone. These substances will also add magnesium to the soil, which hydrangeas need in order to produce beautiful blooms.

Apply the lime or limestone in the fall, as it takes several months for the effects to be noticeable. You can also use wood ash to raise the pH of your soil. Wood ash is more concentrated than lime or limestone, so use caution when applying it. It’s best to apply wood ash directly to the soil

Hydrangeas with blue flowers thrive in soils with a pH level of 5.5 to 6.5, while pink hydrangeas prefer slightly acidic soils with a pH level of 6.0 to 6.5. To change the color of your hydrangeas, simply adjust the soil pH accordingly.

You can lower soil pH by adding an acidifier, such as ammonium sulfate or aluminum sulfate. You can also incorporate naturally acidic organic materials, such as coffee grounds or conifer needles, into the soil.

Remember to retest your soil regularly to monitor effects over time. With a little effort, you can easily change the color of your hydrangeas to match your personal preference.

To produce consistently blue blooms, your soil’s pH will most likely need to be adjusted on a regular basis. When you would usually fertilize your hydrangeas, gently work acidifying soil additives into the top layer of soil around the root zone in early spring.

Also, if you’re trying to make alkaline or neutral dirt more acidic, be sure to add organic matter such as composted leaves, pine needles, or coffee grounds on a regular basis.


Hydrangeas appreciate soil that is rich and moist, but well-draining. The most important factor to consider when planting your hydrangeas in a certain location is the pH balance of the soil.

Happily, it’s quite simple to transform a largeleaf hydrangea’s hue from pink to blue or vice versa.

Blue flowers will appear in acidic soil, however pink blooms will blossom in more alkaline soil. In the case of a poor pH and you want to create a blue hue, simply raise the acidity by adding sphagnum peat moss or nitrogen fertilizer to the soil.

Mulch Your Hydrangea

Mulching is an important step in caring for your hydrangeas. A layer of mulch helps the soil retain moisture, keeps the roots cool in summer, and protects them from extreme cold in winter.

Use a loose, organic mulch such as wood chips or shredded bark. Apply a 3-inch layer of mulch around the base of the plant, being sure to keep it away from the stem. Mulching also helps prevent weeds, so you’ll spend less time tending to your garden.


First and foremost, Nikko Blue Hydrangeas need plenty of light. They should be grown in partial shade, with some morning sun.

Gardeners in the south may wish to provide more shade, while those who live in cooler climates can get away with a location in full sun. All in all, the plants will need six to eight hours of good sunlight to experience full bloom.

Nikko blue hydrangeas will do best in partial sun to full sun locations. They will tolerate some shade, but may not produce as many flowers.


Water your Nikko Blue Hydrangea deeply several times per week to promote strong roots. Once they are established, they will appreciate consistent moisture and you should aim for at least 1 inch of water per week (or more, if you are experiencing especially warm weather).

When watering, aim your hose at the root of the plant to prevent soaking delicate blossoms and leaves—this will aid in preventing fungal diseases and preserving your plant.

Temperature and Humidity

Hydrangea can be grown in a variety of hardiness zones and can even be overwintered in some areas. Mature Hydrangea can handle temperatures as low as 32 degrees Fahrenheit, but younger plants should be kept at temperatures no lower than 35 to 40 degrees Fahrenheit.

Additionally, hydrangeas like average to high humidity and will often thrive in the moist heat of summer. However, if they experience too much dry air, like in an arid, desert climate, the plant’s leaves can wilt or droop.


If you want to change the color of your Hydrangea, there’s no need to feed it more frequently than once a year. Apply a slow-release fertilizer blend designed for shrubs and trees to your plant in the beginning of spring; you may also use organic matter if you like.


Nikko blue hydrangea bushes are lovely enough to be specimen plants in the cottage garden style, and they make attractive specimens when grown in full color—they’re also sometimes used as yard boundaries.

The flowers of this plant, which is native to North America, are actually where the common name originated. Because they are made up mostly of sepals, the flower heads last throughout the fall (though the hue will fade), providing interest to the autumn landscape and making them an excellent choice for dried arrangements. Some farmers appreciate the foliage, while others do not care for it.

Nikko blue hydrangea bushes require little (if any) trimming, but you must be aware that they bloom on old wood.

A rosebush should be pruned at about the same time as it is trimmed each year. The buds are set in late summer to early fall, so you should trim earlier. If you cut after the buds have been placed, you risk losing flowers for next year (but dead branches can always be removed at any time). Prune back until you see healthy bud development.

Common Pests and Diseases

Hydrangeas are susceptible to a number of typical diseases. Botrytis blight is a fungal infection that can cause flower buds to die before they are able to bloom.

Brown or purple spots on the leaves of the plant are yet another symptom. Excess moisture, as well as other factors, can cause both brown and purple spots on the leaves

Infestations of scale or aphids can also be a problem for the plant, particularly if they’re already present in other parts of your landscape or garden. The plant should be treated as soon as possible with a light insecticide or horticultural oil like neem oil to control infestations.


How do I get my Nikko blue hydrangea to bloom?

The color of the blooms on this Nikko Blue Hydrangea is best in acidic soil. The hue of the blooms will be pinker if the soil is more neutral in color. To make your flowers bluer, add aluminum sulfate to the soil. In order for hydrangeas to grow, they require full sunshine or at least partial shade

When should you cut back Nikko blue hydrangea?

Nikko blue hydrangea bushes do not need much (if any) trimming, but the most important thing to bear in mind if you feel compelled to prune them is that they bloom on old wood. Buds are established in late summer or early fall, so pruning should be done before this time.

Do Nikko blue hydrangeas rebloom?

Although Nikko blue hydrangea bushes do not require a lot of pruning, the most important thing to know if you opt to trim them is that they bloom on old wood. The buds are placed in late summer to early fall, so you should prune before then.

How do you keep blue Nikko hydrangeas blue?

In hard water regions, frequent watering causes the growing medium to become more alkaline, even if it begins lime-free. To ensure that your Hydrangea remains as blue as possible, use Vitax Hydrangea Colourant, a powder made of aluminum that you may add to the compost.

What happens if you don’t prune hydrangeas?

Hyacinths on old wood do not require pruning, and their blooms are improved by it. If you leave them alone, they’ll blossom more abundantly the following year. However, go ahead and thin or deadhead gently. Just bear in mind that new shoots may develop the next season, but they will be barren the following year.

Why are my Nikko blue hydrangeas not blooming?

Hydrangeas do not bloom because of incorrect pruning, bud damage caused by winter and/or early spring weather, bad location, and overfertilization. Hydrangea types may blossom on old wood, new wood, or both. Old wood is the current year’s growth, whereas new wood is the following year’s (spring) development.

Do Nikko blue hydrangeas bloom on old wood?

The first pair of buds beneath the old bloom can be maintained by cutting back just to the first pair of buds beneath the old flower in spring. Grow in damp, but well-drained soil in partial shade or bright light.

Does Nikko blue bloom on old or new wood?

Nikko Blue is a “Mophead” Hydrangea with huge round flower heads. This cultivar grows 6′-8′ tall and 6′-8′ wide in part shade and wet, but well-draining soil. Because the Nikko Blue blooms on wood from the previous year, cutting stems back severely in the spring is not suggested.

What to feed hydrangeas to make them bloom?

Hydrangeas thrive when fed an all-purpose fertilizer such as a 10-10-10 N-P-K or 12-4-8 N-P-K. Consider using a fertilizer with more phosphorus to boost the size and number of hydrangea blooms.

Do coffee grounds make hydrangeas blue?

Some gardeners say coffee grounds can be used to color hydrangeas blue. The soil becomes more acidic after being treated with the coffee grounds, allowing the hydrangea to absorb aluminum more readily. Furthermore, peels from citrus fruits, grass clippings, peat moss, and pine needles are thought to have a similar effect.

How tall do Nikko blue hydrangeas get?

Hydrangea grows quickly to a height of 4-6 feet tall and wide. When grown in acidic soil, Hydrangea produces one of the most beautiful Dutch blue hues available. Ideal for purple, pink, or white garden color schemes.

How long does Nikko blue hydrangea bloom?

‘Nikko Blue,’ which blooms in early summer for up to 2 months, is extremely floriferous and creates new flower stems throughout the summer. The foliage is medium green with large, glossy, serrated leaves. It’s a well-known name in mophead hydrangeas because it has established itself as the standard against which other blue hydrangeas are judged.


In order to have beautiful blooms, Nikko blue hydrangeas need six to eight hours of sunlight per day and should be watered deeply a few times a week. You can help maintain humidity levels by spraying the plant with water regularly and fertilizing once a year with a slow-release fertilizer blend designed for shrubs and trees.

Pruning is only necessary if you want to change the color of your flowers; trim back until you see healthy bud development. Hydrangeas are susceptible to fungal diseases like Botrytis blight, so be sure to keep an eye out for any signs of infection and treat it with an insecticide or horticultural oil as soon as possible.

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