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Looking for some shrubs with blue flowers to round out your garden space? Most people that think about blue flowering bushes immediately think of hydrangea. But there’s actually a number of other blue flowering bushes that you can add to your home or garden space to give it a little more color!
Plants with blue flowers in general are fairly unique. You don’t see them very often, and when you do, it often results in a double-take due to their vivid blue blooms. While red shrubs are a bit more common, adding some blue to your garden space will liven it up a bit more.
So what bushes have blue flowers? In the following article, you’ll learn about some of our favorite blue flowered shrubs. You’ll learn their scientific names, what hardiness zones they grow in, and about how big they grow. Let’s take a deeper look at our favorite blue flowering shrubs, with names and pictures of each!
Bellflower
Scientific Name: Campanula carpatica
- Plant Type: Perennial
- Geographical Origin: Mediterranean
- Plant Size: 5 to 7 inches tall
- Sun Exposure: Full sun, partial shade
- Plant Zone: 3-8
Though the Bellflower is not strictly speaking a shrub, this plant is similar to many blue flowering bushes in terms of appearance. The Bellflower plant has dense foliage and lots of slender stems coming out of the main root system, making it look very similar to a small shrub.
The blossoms of the Bellflower are distinctive for their bell shape and pale blue or bluey-purple coloring. The Harebell and Bluebell flowers are a species of the Bellflower, as they too have a blue-colored bloom shaped like a bell.
The Bellflower can thrive in a garden or pot, but some species are invasive and may try to take over your yard. Snipping off the deadheads of the plant can help keep it in check.
Big-Leaf Hydrangea
Scientific Name: Hydrangea macrophylla
- Plant Type: Shrub
- Geographical Origin: Japan
- Plant Size: 5 to 6 feet tall
- Sun Exposure: Full to partial sun
- Plant Zone: 6-9
Growing hydrangea in your garden or yard is very common, as this shrub can grow to hedge-like proportions. It blooms all summer long, with the small flowers forming into rounded clumps of larger blooms.
As the name suggests, the Big-Leaf Hydrangea has large, simple leaves with serrated edges. It is easy to grow, although it may not flower if it doesn’t get enough sun or if you prune it too late in the season.
Though the Hydrangea bloom as a white flowering shrub, or have pink blossoms, highly acidic soil is what brings out blue flowers for this garden favorite. Certain hydrangeas are also more likely to have blue flowers. The blue coloring can go from pale to deep blue. A deciduous shrub, the Big-Leaf Hydrangea will lose its leaves in the autumn and regrow them in the spring.
Blue Butterfly Bush
Scientific Name: Rotheca myricoides
- Plant Type: Shrub
- Geographical Origin: Africa
- Plant Size: 8 feet tall
- Sun Exposure: Full sun, partial shade
- Plant Zone: 8-10
This tropical bush can either function as a staple in your garden or as a houseplant. Though it can reach eight feet tall, you can plant trimmings in a flowerpot and carefully prune them to your desired size. It also grows well as a four-foot-tall shrub.
The Blue Butterfly Bush produces delicate blooms that form into large clumps of blossoms. The flowers themselves are a pale blue and have a similar shape to a butterfly. They attract real butterflies, bees, and sometimes hummingbirds.
Though the Latin name for this bush is Rotheca myricoides, most people know it as Clerodendrum ugandense. Clerodendrum ugandense was the plant’s previous designation, as it was mistakenly thought to be part of the South American Clerodendrum family.
Blue Cardinal Flower
Scientific Name: Lobelia siphilitica
- Plant Type: Annual
- Geographical Origin: North America
- Plant Size: 3 to 5 inches tall
- Sun Exposure: Full sun, partial shade
- Plant Zone: 9-11
Also known as the Great Lobelia or Great Blue Lobelia, the Blue Cardinal Flower is another plant with blue blooms that isn’t exactly a shrub. However, the Blue Cardinal Flower gains a dense, woody base when you have several of these plants together in your yard. Together they give off the look of a shrub with long, upright stems to hold the flowers.
The flowers are either bright blue or violet. They grow around the central stem accompanied by lance-like narrow leaves. The blossoms are usually about one inch in length, with five petals. The upper two petals curl back while the lower three extend downwards, giving this flower a unique shape similar to a Snapdragon.
Blue Plumbago
Scientific Name: Plumbago auriculata
- Plant Type: Shrub
- Geographical Origin: South Africa
- Plant Size: 20 feet tall
- Sun Exposure: Full sun
- Plant Zone: 8-11
The Blue Plumbago is one of the more sprawling blue flowering shrubs, with vine-like branches that creep sideways across your garden. Because of this, a Blue Plumbago needs more room than your average shrub.
With a longer blooming period than other flowering plants, the Blue Plumbago often blooms all year. The flowers are small and grow in clumps. The individual blooms each have five petals and are pale blue or bluey-purple in color.
This shrub can work as a potted plant, especially in cooler areas. However, you should plant it in a container with adequate room for this fast-growing shrub. Careful pruning and sheltering it during colder temperatures will also help a potted Blue Plumbago to thrive.
Blue Potato Bush
Scientific Name: Lycianthes rantonnetii
- Plant Type: Shrub
- Geographical Origin: South America
- Plant Size: 6 feet tall
- Sun Exposure: Full sun
- Plant Zone: 10-11
Also known as Paraguay Nightshade and Blue Solanum Shrub, this perennial shrub is a relative of vegetables like the potato, tomato, or eggplant. Unlike these plants, the Blue Potato Bush is poisonous and not a good addition to your vegetable garden.
Though it can’t help you grow your own food, the Blue Potato Bush makes a beautiful addition to a front garden and can even function as a hedge or a tree, depending on how you prune it.
The flowers are small and blue, with a darker star-shaped pattern along the inside of the petals. It can serve as an indoor potted plant as well. The Blue Potato Bush will put out its poisonous red berries after the flowers, so if you have children or pets, be sure to keep them away from the plant during this time.
Blue Rose of Sharon
Scientific Name: Hibiscus syriacus
- Plant Type: Shrub
- Geographical Origin: East Asia
- Plant Size: 8 to 12 feet tall
- Sun Exposure: Full sun
- Plant Zone: 5-9
A sterile strain of the more popular Rose of Sharon, the Blue Rose of Sharon will not produce working seeds. However, this gorgeous plant provides worthwhile leafy greenery and fairytale-like blooms to your yard or garden.
With a shorter blooming period from mid-summer to autumn, each flower will only bloom a single day at a time. The flowers are a pale blue and about four inches across in diameter. They are delicate and lace-like blossoms with a layering of petals.
The Blue Rose of Sharon is a structural shrub, making it very useful as a hedge or yard border. A deciduous bush, it will lose its broad leaves every fall.
This version of the plant is also known as Blue Chiffon in garden centers. The flowers of the Rose of Sharon can look like lighter shades of blue, to a shrub with lavender flowers, depending on the plant.
Bluebeard
Scientific Name: Caryopteris x clandonensis
- Plant Type: Shrub
- Geographical Origin: Mongolia
- Plant Size: 2 to 3 feet tall
- Sun Exposure: Full sun
- Plant Zone: 5-9
Also known as Blue Mist or Blue Spirea, the Bluebeard plant has a later blooming season, usually commencing in late summer and ending in the fall.
The dense, large leaves provide a thick base for the plant while flowering stems rise above. The leaves are often fragrant, giving out a gentle aroma similar to eucalyptus. The flowers themselves are small and pale blue or sometimes white. They clump together every few inches around the central stem, with each lower clump blooming first.
As the flowers open up, they put out long blue whiskers, giving them a similar look to thistles. The Bluebeard plant will attract butterflies and hummingbirds to your garden as summer comes to an end.
Blue Rhododendron
Scientific Name: Rhododendron
- Plant Type: Shrub
- Geographical Origin: Asia
- Plant Size: 2 to 3 feet
- Sun Exposure: Partial sun
- Plant Zone: 6-10
The Blue Rhododendron, or “Blue Tit” Rhododendron, is the blue-flowered version of the traditional shrub. Commonly utilized as a yard border or hedge, the Rhododendron is an evergreen with small dark leaves that last all year. As it is so dense and easily spread, the Blue Rhododendron needs careful pruning every season.
The flowers of the Blue Rhododendron grow in groups of three or five. The blossoms have trumpet shapes and usually emerge as a pale bluey-purple before darkening into a deeper blue.
Blue False Indigo
Scientific Name: Baptisia australis
- Plant Type: Perennial
- Geographical Origin: Central and North America
- Plant Size: 2 to 4 feet tall
- Sun Exposure: Full sun, partial sun
- Plant Zone: 3-9
Though not technically a shrub, the Blue False Indigo has a bushy base made up of large, dense leaves. A member of the pea family, Blue False Indigo uses several thin stalks to display its small flowers. Though not the source of real indigo, its juices can sometimes act as a substitute.
The blossoms are a pale blue to blue-purple color. They look very much like the flowers of the Pea plant, with three to four main petals that curve away from each other.
When emerging from the earth, new shoots of Blue False Indigo can resemble asparagus. However, this plant can be toxic to humans, especially children, and should not be eaten.
California Lilac
Scientific Name: Ceanothus concha
- Plant Type: Shrub
- Geographical Origin: North America
- Plant Size: 4 to 6 feet tall
- Sun Exposure: Full sun
- Plant Zone: 7-10
Also known as Soap Bush or Ceanothus, the California Lilac is one of the easiest blue flowering shrubs to grow. The shrub doesn’t need much coaxing to thrive, and it can sprout faster than you think.
Just like any other Lilac bush, the California Lilac has clusters of tiny flowers that form bottle brush shapes all over the plant. Each individual flower is a slender trumpet-like shape, and together with dozens of its fellows, they form stunning cone-like blooms.
The California Lilac has a range of blue colors, from darker blues to paler purple-blue hues. It attracts birds, bees, and butterflies. It can also function as a stand-alone shrub or tree or a partial yard barrier.
Chaste Tree
Scientific Name: Vitex agnus-castus
- Plant Type: Shrub
- Geographical Origin: Mediterranean
- Plant Size: 3 to 16 feet
- Sun Exposure: Full sun
- Plant Zone: 6
The Chaste Tree looks similar to a Lilac bush but does better in climates with hotter summers. It has long, spiky leaves and cones of flowers. The flowers are either white, pink, or a purply-blue. However, the individual blooms are less similar to those of Lilacs, as they don’t grow quite so dense.
Chaste Trees can be stand-alone shrubs or part of a yard border. They are sometimes looked to for medicinal purposes to combat premenstrual syndrome, among other things. However, there is no conclusive evidence that a Chaste Tree can be beneficial as a medicine or health product.
Dwarf Morning Glory
Scientific Name: Evolvulus glomeratus
- Plant Type: Perennial
- Geographical Origin: North and South America
- Plant Size: 6 to 12 inches tall
- Sun Exposure: Full sun
- Plant Zone: 10-11
A diminutive version of the Morning Glory vine, Dwarf Morning Glory can function as a small bush or potted plant. The stems of the plant keep the vine-like quality of the parent version, allowing the foliage of the Dwarf Morning Glory to become woody and dense.
The flowers are wide-spread trumpet shapes up to two inches across in diameter. Unlike other blue flowering plants, the Dwarf Morning Glory blossoms are a royal blue color, providing a definitive splash of blue for your garden. The center of each flower is a gold and white circle, allowing the bright blue edges even more definition.
Lily of the Nile
Scientific Name: Agapanthus
- Plant Type: Perennial
- Geographical Origin: Africa
- Plant Size: 22 to 26 inches tall
- Sun Exposure: Full sun
- Plant Zone: 6-11
The Lily of the Nile is an impressive flower with a shrub-like base. If you need a smaller, bushy plant with blue flowers for the front part of your garden, the Lily of the Nile can do the job well. It can also thrive as an interior potted plant.
Though many versions of this plant boast blue flowers, there is a range of colors from pale to darker blue, white, and white with blue stripes. When closed, the blossoms have a similar look to pea pods. However, when opened, the flowers have a delicate and thin star shape.
The individual flowers grow in a rounded clump at the top of thin stalks that poke up from the dense foliage.
Russian Sage
Scientific Name: Perovskia atriplicifolia
- Plant Type: Shrub
- Geographical Origin: Central Asia
- Plant Size: 3 to 5 feet tall
- Sun Exposure: Full sun
- Plant Zone: 5-10
This sage-like plant is a subshrub, making it a more diminutive choice for gardens or yards. This plant consists of woody foliage and tough, square-shaped stems peppered with small flowers.
Often, Russian Sage is more purple than blue, but it still provides a similar aesthetic to your garden. However, you can also find the “Blue Spire” variation of Russian Sage, which puts out flowers of a more royal blue hue.
The Russian Sage gives off a fragrance when crushed, similar to other sages or lavender. When allowed to grow out, each stem holds a triangle-like formation of flowers separate from its fellows for a sparser appearance.
Salvia
Scientific Name: Salvia
- Plant Type: Shrub
- Geographical Origin: Asia, the Americas, Europe
- Plant Size: 18 inches to 5 feet tall
- Sun Exposure: Full sun
- Plant Zone: 3-9
Also known as sage, this shrub bears many similarities to the Russian Sage above. It can thrive in a garden, as a border plant, or in a container. It blooms from summer into autumn and attracts bees and butterflies.
Salvia grows out of a dense base with spiky, upright stems. The flowers from these stems are dark blue to dark purple, although some variations are red or pink. Each stem holds a cluster of small blossoms surrounded by colorful bracts. The bracts are either the same shade as the flowers or a complementary one.
Spiked Speedwell
Scientific Name: Veronica spicata
- Plant Type: Perennial
- Geographical Origin: Europe
- Plant Size: 18 to 24 inches tall
- Sun Exposure: Full sun
- Plant Zone: 3-9
Spiked Speedwell is a very low-maintenance plant, meaning you can grow it in your garden, on rocky terrain, or in a container as you please. Though not a shrub, the Spiked Speedwell will cultivate thick foliage, especially with several plants, to give you the look of a bush or shrub.
As the name suggests, Spiked Speedwell boasts long stems with spiky flower formations. The individual flowers are very small and bright blue or bluey-purple in color. Collectively, the flowers come together in a bottle-brush formation similar to a Lilac bush.
Spike Speedwell is non-invasive but a fast grower, meaning you can have a sudden rash of the plant from any seeds you sow.
Final Thoughts
The good news is, when you want a blue flowering shrub for your yard or garden space, there’s plenty to pick from! Yes, some of these shrubs have a shade of violet, but many of them are quite blue when seen in person. You can also choose shrub like plants with blue flowers if you prefer not to commit to an actual shrub. Regardless of what you decide to choose, there are plenty of blue flower bushes that can make your home or garden space a visual specimen!
