12 Blue Hydrangea Varieties Bursting With Color (2024)

Blue, blue, blue! In all my gardening ventures, whether it be perennial gardening, annual gardening or floral work the number one color request I had was for more blue flowers! It’s really easy to understand why blue is so sought after in gardens. It is a very calming and relaxing color, it matches with most other colors, and it does seem like a challenge to find a true blue.

Oftentimes plants with blue blooms are grown as annuals, and they really add a pop of needed color in your gardens. If you are looking for a shade of blue that will come back year after year, hydrangeas can be one of the best options.

The bigleaf hydrangeas are a moderately sized plant that would be great as a garden border. They sport larger leaves which pair nicely with the large flowers. Bigleaf hydrangeas can have lacecap or mophead flowers. Mophead flowers are pom pom shaped flowers made up of made many florets.

Hydrangea serrata, or mountain hydrangea, is a perennial shrub that tends to be a little smaller than the bigleaf. The leaves are longer and more narrow, making them more delicate especially with the lacecap flowers. Lacecap flowers are made up of larger florets that surround a cluster of flowers that look like unopened flower buds. Adding these to a perennial garden would be a great choice.

Hydrangea Macrophylla

Hydrangea macrophylla varieties are very popular, and are considered to have “longer leaves” when compared to other varieties. This species originated in Japan, and since has grown into many different varieties, all of which are “big leaf” hydrangeas. These perennial shrubs are low growing when compared to other varieties. They also have plenty of blue cultivars which we will look at next.

Big Daddy

This plant produces very large sky blue blooms that can reach up to 14 inches across. Situate this mophead covered plant in partial shade to full shade to keep it from drying out. The blooming season for ‘Big Daddy’ is from Summer to Fall, however its glossy, deep green foliage will be attractive until after a frost.

‘Big Daddy’ will bloom on old wood AND new wood (plot twist!). ‘Big Daddy’ will grow about five to six feet tall in a nice mounded form. This plant is tolerant of cool and hot climates (hardy in USDA zones 6-9), making it a great selection no matter where you live… Well, almost!

Endless Summer

If you close your eyes and you try to picture the perfect blue hydrangea, you are most likely picturing this beauty. The ever popular ‘Endless Summer’ is a true reblooming hydrangea. This is a collection of five varieties. Boasting its reputation as the first reblooming hydrangea, this plant will bloom on old wood and new wood, like ‘Big Daddy’.

Your plant will be covered in perfectly blue mophead blooms accented with bright green leaves from spring through fall. Growing to about three or five feet in height, ‘Endless Summer’ is very versatile in your garden.

Use it as a very low maintenance hedge, in a container, or in groupings throughout your gardens. ‘Endless Summer’ is hardly from zones 4-9 making it a great choice for almost the entirety of the United States.

Endless Summer Twist and Shout

Okay- so we’ve already learned that the Endless Summer collection is a wonderful group of hydrangeas that are reblooming. I had to include this one, as it has really pretty lace cap blooms. Twist and Shout is a very dependable bloomer with vivid colored flowers that range from periwinkle to deep pink depending on your soil.

This blue flowering shrubs red stems add beautiful winter interest to your garden. Grows up to three to five in height in an upright rounded habit. Just like the original, Twist and Shout is hardy in zones 4-9.

Image Credit: Michele Walfred via Flickr (Image Use Allowed With Attribution)

Générale Vicomtesse DeVibraye

This is a French stunner. Coming in at a pale blue, these flowers cover this mounded shrub. As with most of the mounded hydrangeas the uses are really endless, I do love them in a hedge. There’s something about a big old row of those giant flowers that just makes you swoon.

This plant will grow from four to six feet, and loves morning sun and afternoon shade. The foliage is a nice healthy green. This is a really nice cut flower. If left to dry when the blossoms are blue, they will fade to a blue-green creating an antique look. Blooming from summer through fall the ‘Generale’ is hardy in zones 6-9.

Let’s Dance Rhythmic Blue

This hydrangea is very easy to grow and requires no pruning! ‘Rhythmic Blue’ has deep blue flowers that will bloom from mid summer to early fall. Like the Endless Summer collection, this is another reblooming type of hydrangea. Flowers will bloom on new wood and also old wood giving you months of fresh flowers.

This mounded shrub will grow to about four feet, and would be a really pretty addition to a perennial garden. ‘Rhythmic Blue’ was specifically developed to withstand the cold winters of the midwest and is nice and hardy from zones 5-9.

Mathilda Gutges

This is one of my personal favorites. The flowers on ‘Mathilda’ are a very rich blue (almost purple) and occasionally have a lighter blue center giving them a tie-dyed appearance. Bloom time is from early summer through the fall.

This hydrangea is a nice size for a hedge or foundation planting, growing from three to six feet. Plant in partial sun. ‘Mathilda Gutges’ blooms on old wood, so prune right after the blooming season has ended. Hardy from zones 5-9.

Image Credit: Michele Walfred via Flickr (Image Use Allowed With Attribution)

Nantucket Blue

This mophead hydrangea is covered in blooms in a beautiful sea blue. Its variety name is no accident, this is a seaside favorite that has been seen decorating the classic white picket fences of Nantucket.

‘Nantucket Blue’ is a reblooming hydrangea, flowering on both old and new wood. Grows to about six feet, this hydrangea would make a great border. Hardy in zones 5-9, this is a great option if you want the beautiful blue color, and want it to stay blue.

Nikko Blue

This is a gorgeous option for a shrub with blue flowers. It loves partial shade. Its flowers are abundant through the early summer. Growing to six feet tall ‘Nikko Blue’ will provide enough privacy to be used for a screen, or planted along a wall or fence. It blooms on old wood, so be wary when you prune.

Old wood bloomers typically don’t need much pruning, but if you need to remove some growth to maintain the shape or size it is best to do so right after they bloom in the summer, usually in August or September. Pruning later than September could cause your hydrangea to not bloom in the following year.

Penny Mac

‘Penny Mac’ is a great choice if you don’t love the workload that can sometimes come with hydrangea maintenance. ‘Penny Mac’ grows quickly to six feet high and four feet wide. This hydrangea is covered with giant blue mophead flowers that last all summer long.

Pruning is not necessary on this plant unless you have some winter damage, and even that should be minimal. This is a weather tolerant option as it is hardy from zones 5-9. This variety has become quite popular as a result of its ease of care and low maintenance needs.

Early Blue

‘Early Blue‘ is a smaller compact variety that’s great for container planted gardens. They are easy to care for, easy to propagate, and have longer bloom times compared to other varieties. They have a deeper blue color, but can also come in another shade called ‘Early Pink.’

Because they are smaller, they can make a great border or edge plant for your garden. Their blooms can stretch all the way into first frost, depending on your hardiness zone. They are hardy from zones 5-9 and will thrive with only basic maintenance.

Hydrangea Serrata

Hydrangea Serrata is native to Korea and Japan. A small and more compact option, this hydrangea species also makes for a great perennial around garden borders. You can expect them to grow to about 2 feet tall, and hardy into colder climates. These hydrangeas aren’t what many gardeners think of when a “traditional” hydrangea comes to mind, but they look fantastic and give you plenty of options if you are looking to add a pop of blue color to your garden space.

Blue Billow

The flowers on this hydrangea are a delicate lacecap in a sky blue, but they cover the plant making quite the show stopper in your yard. These flowers will last for weeks beginning in early to midsummer. The leaves on Hydrangea serrata are pointy and more narrow than on the bigleaf hydrangea.

The leaves will turn burgundy in the fall. ‘Blue Billow’ will grow to four feet in height but can grow to ten feet wide. It loves partial shade, and is hardy from zone 5-9. ‘Blue Billow’ is cold hardy, however, the warmer the climate, the more consistent the blooms will be!

Bluebird

‘Bluebird’ is another exceptional lacecap hydrangea. Light blue florets surround a large clump of richer blue fertile flowers that give this shrub a two toned look, making it unique. This shrub grows in a mounded form and grows to four feet high and wide.

The leaves are a dark green and frame the flowers really nicely. The leaves will turn red in the fall, extending the season of interest. The flowers bloom throughout the summer making ‘Bluebird’ a really pretty hydrangea to use as a border, or as an accent plant. ‘Bluebird’ loves partial shade, Hardy in zones 6-9.

Color Changing

Hydrangea macrophylla, or bigleaf hydrangea, and to a certain extent H. serrata, will react to the pH of your soil as well as the level of aluminum in your soil. Soils that are more acidic, below 5.5 pH, will favor blue flowers by allowing the hydrangea to absorb more aluminum.

If the blooms on your should be blue hydrangeas have been looking a little more pink than you were hoping for this is an easy fix. Aluminum sulfate is available at most garden centers, and is the best product to use to enhance the blues of your flowers. Use a “less is more” approach when applying this to your plants.

A drench of one tablespoon of aluminum to one gallon of water is the safest application rate. If the plant is dry, water before applying this solution. This method should only be used twice a year: once in April and once in May.