20 True Blue Flowers for Your Garden

Many plants marketed as blue are actually closer to purple. Petunias are a prime example. True blue is a pure blue hue that isn’t shaded with black, white, or any other color. This color is rarely found in nature because few organisms can create the true-blue pigment. 

Why We Love Blue in the Garden

Blue makes us think of water and sky, giving a cooling touch to the landscape. It is a calming color, making a garden full of blue the perfect place to unwind after a hectic day. 

• Blue also plays well with others, emphasizing their colors, and is great for cooling hot colors down. 
• It can also be used to create an illusion of more space in a small garden. 
• Since bright colors jump forward and dark colors recede, planting deep blues on the far ends of your garden will make them seem farther away. 
• When integrating blues into your garden, separate them from each other. 
• Create color echoes by looking for blue in a contrasting eye, throat, or stripe and pairing it with a totally blue blossom in a matching hue to highlight it. 
• Gray foliage goes well with blue, and some of the most popular color combinations include blue: blue, pink, and white; blue and yellow; or light blue and apricot.

True Blue Flowers for the Garden

Make room for some of these blue blossoming plants in your garden:

Bulbs That Produce Blue Flowers

1. Chionodoxa

Aptly called Glory of the Snow, Chionodoxa blooms very early, often pushing up through snow cover. Their sky-blue blossoms start the season right.  Inexpensive, the tiny bulbs are perfect for naturalizing.

• 4 to 8 inches tall
• Full to half-day sun
• Zones 3 to 10
• Blooms in April 

2. Grape Hyacinths 

The tiny grape hyacinths continue the color, blossoming a little later in the spring. Fragrant Muscari aucheri ‘Blue Magic’ is a two-tone blue and is just one of the many true blues in this plant family. Varieties of M. armeniacum are generally a darker blue.

• 6 to 8 inches tall
• Full to part sun
• Zones 4 to 9
• Blooms in May 

Annual Blue Flowers

Annuals bring long-lasting color to your garden. Deadhead the fading blossoms to prolong the show. The following annuals should bloom from spring to fall.

3. Bachelor’s Buttons 

Also called cornflower, Bachelor’s buttons (Centaurea cyanus) come in a range of colors, so unless you want a mix, look for ‘Blue Boy’ or ‘Florist Blue Boy.’ The blossoms make a great cut flower or edible garnish. Leave a few to seed out at the end of the summer, and they may self-sow, returning next year. 

• 2 to 3 feet tall
• Full sun
• Direct sow

4. Borage 

With its star-shaped blue blossoms, borage is edible with a mild cucumber flavor. An annual herb, it is a good companion for tomatoes, cabbage, squash, and strawberries when planted in the vegetable garden. It also attracts pollinators and other beneficial insects. Another willing self-sower, if left to form seeds, the plants will pop up all over your garden next spring.

• 18 to 30 inches tall
• Full sun
• Direct sow

5. Salvias 

Salvia farinacea ‘Victoria Blue’ and ‘Blue Bedder’ are the two true blue salvias we grow to sell to florists and put in our bouquets, but I am sure there are others. The 6 to 8-inch long spikes of blossoms keep coming until a hard frost kills the plant. See the Salvia Growing Guide.

• 18 to 24 inches tall
• Full sun to part shade
• Transplant or direct sow

6. Floss Flower 

Good for cutting, floss flowers (Ageratum houstonianum) are usually grown as annuals. ‘Blue Horizon’ is a cut flower we like for its fuzzy blue blossoms. The more you cut, the more flowers it produces. ‘Tall Blue Planet’ is another good variety for cutting.

• 2 to 3 feet tall
• Full sun
• Transplant

7. Dwarf Lobelia 

A tender perennial hardy that grows only in zones 9 to 11, Dwarf Iobelia (Lobelia erinus), is grown annually in most of the country. Prized for its bright blue flowers, it is frequently used in container plantings, hanging baskets, and window boxes. It blooms from spring through fall but prefers cool weather, so keep it well-watered during hot spells. If your plant dies back in mid-summer, it will rebound with new growth and more flowers after being cut back.

• 12 inches tall
• Full sun to part shade
• Seed or transplants

8. Forget-me-not  

This beauty is not one to forget. ‘Indigo Blue’ (Myosotis sylvatica) is an easy-to-grow heirloom. Plants are biennial, blooming in their second year and then dying back. Leave the spent flower heads so they can reseed themselves, and you will have plants to enjoy again next year.

• 12 inches tall
• Full sun to part shade
• Zone 3 to 10
• Spring bloomers

Perennial Blue Flowers

9. Amsonia 

Often called Bluestar because of its sky-blue, star-shaped blossoms, this North American native is attractive to butterflies, but rabbits and deer shun the milky sap found in its narrow leaves. There are several different native species, and a few are from Europe and Asia. Varieties to choose from abound, including ‘Storm Cloud’ and ‘Blue Ice’.  

• 2 to 3 feet tall and wide
• Full sun to part shade
• Zones 3 to 10
• Blooms late spring to early summer

10. Virginia Bluebell 

Another North American native, Virginia Bluebell (Mertensia virginica), bears loose clusters of inch-long, trumpet-shaped blossoms that start as pink buds and mature to light blue. A spring ephemeral, they thrive in moist woodlands. After blooming, the plants die back to the ground and go dormant. 

• 18 to 24 inches tall
• Part shade to full shade
• Zones 3 to 8
• Blooms April to May

11. Himalayan Blue Poppies 

A highly prized rarity, true blue poppies (Meconopsis) can be challenging to grow. They need moist, slightly acidic soil and a cool location protected from direct sunlight. Native to Tibetan mountains, they are definitely not suitable for hot, humid southern gardens. If your plant is happy, it will self-seed, forming a colony, but alas, they are short-lived. 

• 4 feet tall
• Dappled shade
• Zones 5 to 7
• Blooms late spring to early summer 

12. Delphiniums 

Delphiniums supply a beacon of blue during the height of summer. The tall flower spikes can be brittle and will benefit from support, especially in windy locations. Many named hybrids are available, including ‘Guardian Blue,’ ‘Aurora Blue,’ and ‘Blue Donna, ’ which make stunning cut flowers. If early stems are cut back after blossoming, they may rebloom in the fall.

• 3 to 4 feet tall
• Sun to part shade
• Zones 3 to 7
• Blooms in summer 

13. Balloon Flowers 

With puffy buds that look like they have been inflated with air, the name balloon flower (Platycodon grandiflorus) is fitting. When finally opened, the five petals form a star. ‘Double Blue’ has twice the petals. Tall varieties could use some support to keep them upright, but there are many heights to choose from, even a tiny dwarf variety, ‘Sentimental Blue’, that tops out at 6 to 8 inches tall. Deeply tap-rooted, the plants are long-lived. 

• 1 to 3 feet tall
• Full sun to part shade
• Zones 3 to 8
• Blooms mid to late summer

14. Blue Cardinal Flower

Native to wet marshy areas east of the Rockies, blue cardinal flowers (Lobelia siphilitica) are excellent for locations with moist soil or in a rain garden. Bees love the tubular blossoms of these perennials.

• 2 to 4 feet tall
• Sun to part shade
• Zones 4 to 9
• Blooms July to Oct

15. Woodland Phlox 

A fragrant, low-growing native ground cover, Woodland phlox (Phlox divaricata) is great for shade gardens. Butterflies love it, and it is a host plant for the hummingbird clearwing moth and gray hairstreak butterfly. See how to plant and grow phlox.

• 12 inches tall
• Part shade to shade
• Zones 3 to 8
• Blooms April to May

16. Blue False Indigo 

A native plant, blue false indigo (Baptisia australis), was used by some Native Americans and settlers to produce a blue dye. Individual pea-type blossoms are produced on 1-2 foot tall flower spikes. Shrub-like in growth with blue-green leaves, once established, they are long-lived plants. An important nectar source for bees, they are host plants for many species of butterflies.

• 3 to 4 feet tall and wide
• Full to part sun
• Zones 4 to 9
• Blooms May to July

17. Jacob’s Ladder 

With its blue bell-shaped flowers, Jacob’s ladder (Polemonium caeruleum) is perfect for your shady garden. If deadheaded, the flowers may rebloom. A native species, P. reptans, is only 12 inches high, making an excellent ground cover in moist, shady areas.

• 18 to 24 inches tall
• Part to full shade
• Zones 4 to 8
• Blooms April to June

Vines With Blue Blooms

18. Clematis 

A vine with blue blooms, clematis offers many variations, from the dainty nodding bells of ‘Blue Dancer’ to the large double-flowering ‘Multi Blue.’ Some clematis die back to the ground every winter and bloom on new growth, while others survive the winter and blossom twice—once on last year’s growth and again on new growth.

• 6 to 8 feet tall
• Full to part sun
• Zones 4 to 11, depending on the species
• Bloom from spring into fall, also depending on the species

Shrubs With Blue Flowers

19. Hydrangea 

Ah, the perfect blue hydrangea. ‘Endless Summer,’ Nikko Blue, ‘Let’s Dance Blue Jangles,’ and ‘Rhythmic Blue’ are all big-leaf hydrangeas that produce blue flowers if grown in acidic soil. See the Hydrangea Growing Guide.

• 4 to 6 feet tall and wide
• Full to part sun
• Zones 4 to 9
• Bloom time varies depending on the variety

20. Blue Spirea 

Also called blue mist or bluebeard, this Spirea (Caryopteris clandonensis) has blue flowers that last into fall. In cold regions, the top growth may die back in winter, but it will regrow from the roots. Bees, butterflies, and other beneficials love its flowers, making it a nice addition to your pollinator-friendly garden.

• 2 to 4 feet tall and wide 
• Full sun
• Zones 5 to 9
• Blooms late summer into fall

As you can see, the colors range from pale icy blue to cobalt and deep indigo. Have fun painting your garden with broad strokes and highlights of blue!

Check out our stories on 20 Yellow Flowers, 20 Pure White Flowers, 20 Pink Flowers, and 20 Purple Flowers.

What are your favorite true blue flowers? Let us know in the comments below!