The Best Blue Flowers For Summer Blooms (2024)

From agapanthus to hydrangeas, explore the best blue flowers to bring a pop of color to your summer garden.

Amidst the fiery oranges, sunny yellows, and passionate reds of summer, blue flowers offer a refreshing contrast. Their cool serenity evokes the blue skies and the tranquil depths of the sea, doesn’t it?

These sapphire, cerulean, and indigo blooms bring a sense of peace and harmony to the garden, providing a welcome respite from the blazing sun and sweltering temperatures.

Every year, as the days grow longer and warmer, I eagerly anticipate the explosion of blue blossoms that will transform my gardens into a peaceful haven. Do you love them as much as I do?

Whether you’re seeking a touch of elegance, a pop of vibrancy, or a dash of whimsy, blue flowers offer a refreshing alternative to the traditional summer palette. Wait until you see how many options there are!

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Best Annual Blue Flowers to Brighten Your Summer

If you want to add a long-lasting blue hue to your summer garden, look no further than flowering annuals. Here are some beautiful blue annual flowers to try!

Borage (Borago officinalis)

This charming herb is a culinary and pollinator powerhouse. Its star-shaped blue flowers are not only a visual delight but also a tasty addition to salads and drinks, boasting a delicate cucumber flavor. I’ve also found it to me a great companion plant in my vegetable and cutting gardens.

• USDA Hardiness Zones: 2-11
• Sun Requirements: Full sun
• Soil Conditions: Well-draining, average to fertile
• Size: 2-3 feet tall, 1-2 feet wide
• Pollinators: Bees, butterflies
• Deer Resistance: Low, Deer may nibble on it

Lobelia (Lobelia erinus)

These dainty flowers create a sea of blue when planted en masse in hanging baskets, containers, or garden beds. Their trailing habit makes them perfect for spilling over edges and adding a touch of whimsy to your landscape. And it’s one of my favorite flowering annuals for summer that I incorporate in my planters.

• USDA Hardiness Zones: Annual in most areas, perennial in zones 10-11
• Sun Requirements: Full sun to part shade
• Soil Conditions: Well-draining, moist
• Size: 6-12 inches tall, trailing
• Pollinators: Bees, butterflies, hummingbirds
• Deer Resistance: Moderate (deer generally avoid it)

Ageratum (Ageratum houstonianum)

Also known as floss flower, ageratum is beloved for its fluffy, pompom-like clusters of tiny blue, pink, or white flowers that bloom all summer long. This low-growing annual is a popular choice for borders, edging, and containers. I started ageratum from seed this year and also bought a few flats from the nursery. While both are easy to grow and look really pretty, I’m in LOVE with the ones that I started from seed.

• USDA Hardiness Zones: Grown as an annual in most areas, perennial in zones 10-11
• Sun Requirements: Full sun to partial shade (flowers best in full sun)
• Soil Conditions: Well-draining, fertile soil
• Size: 4 to 36 inches tall, 6 to 18 inches wide (depending on variety)
• Pollinators: Bees, butterflies
• Deer Resistance: High

This was my first year growing it in my flower garden, and I have to say…I am a huge fan now! Ageratum looks really pretty with scaevola, moonbeam coreopsis, zinnias, and coneflowers.

Bacopa (Sutera cordata)

A vigorous and heat-tolerant ground cover, bacopa is known for its dainty white or pale blue flowers that bloom profusely throughout the summer. It’s a versatile plant that thrives in hanging baskets, window boxes, and as edging for pathways.

• USDA Hardiness Zones: Annual in most areas, perennial in zones 9-11
• Sun Requirements: Full sun to part shade
• Soil Conditions: Well-draining, moist
• Size: 6-12 inches tall, trailing
• Pollinators: Bees, butterflies
• Deer Resistance: High (deer generally avoid it)

I use bacopa all the time in my planters and love it when paired with begonias, geraniums, colocasia, caladiums, euphorbia, and impatiens.

Love-in-a-Mist (Nigella damascena)

This unique flower is beloved for its delicate, feathery foliage and intricate blue blossoms. After the flowers fade, intriguing seed pods emerge, adding further interest to the garden.

• USDA Hardiness Zones: 2-11 (annual)
• Sun Requirements: Full sun to part shade
• Soil Conditions: Well-draining, average
• Size: 1-2 feet tall, 1 foot wide
• Pollinators: Bees, butterflies
• Deer Resistance: High (deer generally avoid it)

Best Blue Perennials for Summer: Long-Lasting Color for Your Garden

Level up your summer landscape with these vibrant blue perennials that not only add a cool touch but also come back year after year, rewarding you with their stunning blooms and attracting beneficial pollinators.

Salvia (Salvia spp.)

Salvias are a diverse group with many blue-flowering varieties. They’re adored for their long blooming period and their ability to attract a plethora of pollinators, from bees to hummingbirds.

• USDA Hardiness Zones: Varies depending on species, typically 4-11
• Sun Requirements: Full sun
• Soil Conditions: Well-draining, average to dry
• Size: Varies greatly depending on species, from 1-5 feet tall
• Pollinators: Bees, butterflies, hummingbirds
• Deer Resistance: High (deer generally avoid it)

I grow several varieties of salvias in my flower gardens and think it looks best with coneflowers, coreopsis, nepeta, yarrow, agastache, and shasta daisies.

Catmint (Nepeta spp.)

With their aromatic foliage and lavender-blue flowers, catmints are a delight for both humans and felines. They’re easy to grow and make excellent ground covers or edging plants.

• USDA Hardiness Zones: 3-8
• Sun Requirements: Full sun to part shade
• Soil Conditions: Well-draining, average
• Size: 1-3 feet tall, spreading
• Pollinators: Bees, butterflies, hummingbirds
• Deer Resistance: High (deer generally avoid it)

Catmint is one of my favorite perennials to grow due to it’s low-maintenance nature and deer resistance. I love it planted among coreopsis, salvias, coneflowers, hardy hibiscus, lavender, and roses.

Delphinium (Delphinium spp.)

These majestic plants produce tall spires of vibrant blue flowers, creating a dramatic focal point in the garden. They’re perfect for adding height and vertical interest to borders.

• USDA Hardiness Zones: 3-7
• Sun Requirements: Full sun
• Soil Conditions: Well-draining, fertile
• Size: 3-6 feet tall, 1-2 feet wide
• Pollinators: Bees, hummingbirds
• Deer Resistance: Low (deer may eat it)

Globe Thistle (Echinops ritro)

These eye-catching flowers resemble spiky blue globes, adding a touch of whimsy to the garden. They’re drought-tolerant and attract butterflies and bees.

• USDA Hardiness Zones: 3-8
• Sun Requirements: Full sun
• Soil Conditions: Well-draining, average to dry
• Size: 3-4 feet tall, 2-3 feet wide
• Pollinators: Bees, butterflies
• Deer Resistance: High (deer generally avoid it)

I had globe thistle in my former flower garden and it was tough as nails! You can’t beat the periwinkle color and thought it looked really striking with bee balm and coneflowers.

Balloon Flower (Platycodon grandiflorus)

These charming flowers get their name from their unique balloon-like buds, which open into star-shaped blue blossoms. They’re relatively low-maintenance and make lovely additions to borders or rock gardens.

• USDA Hardiness Zones: 3-8
• Sun Requirements: Full sun to part shade
• Soil Conditions: Well-draining, average
• Size: 1-2 feet tall, 1-2 feet wide
• Pollinators: Bees, butterflies
• Deer Resistance: Moderate (deer may nibble on it)

Agapanthus (Agapanthus spp.)

Also known as Lily of the Nile, agapanthus boasts striking clusters of blue or purple trumpet-shaped flowers atop tall stems. They’re drought-tolerant and thrive in sunny spots.

• USDA Hardiness Zones: 7-11 (some varieties are hardy to zone 6)
• Sun Requirements: Full sun to part shade
• Soil Conditions: Well-draining, average to fertile
• Size: 1-4 feet tall, 1-2 feet wide
• Pollinators: Bees, butterflies
• Deer Resistance: High (deer generally avoid it)

We visited Napa a few years ago, and I was really enthralled by the agapanthus gardens at some of wineries. I saw this one at a local nursery and bought a bunch so I could grow it here in my zone 6b garden. I may need to dig it up and overwinter it indoors due to its hardiness.

Russian Sage (Perovskia atriplicifolia)

Though not a true sage, this drought-tolerant perennial boasts fragrant, silvery foliage and airy spikes of lavender-blue flowers that bloom for weeks. It’s a low-maintenance beauty that thrives in hot, sunny locations and attracts a plethora of pollinators.

• USDA Hardiness Zones: 4-9
• Sun Requirements: Full sun
• Soil Conditions: Well-draining, dry to average; tolerates poor soil
• Size: 3-5 feet tall, 2-4 feet wide
• Pollinators: Bees, butterflies
• Deer Resistance: High

Another perennial favorite, Russian sage looks incredible with coneflowers, coreopsis, blazing star, ornamental grasses, and black eyed susans.

Best Blue Flowering Shrubs for Summer: Season-Long Blue Hues

Embrace the enduring beauty of blue with these flowering shrubs that provide a stunning backdrop of blue hues throughout the summer season, adding structure and elegance to your landscape.

Hydrangea (Hydrangea spp.)

These beloved shrubs are famous for their large, showy blooms, which can be blue, pink, or white depending on the variety and soil pH. Blue hydrangeas are particularly sought after for their cool, serene hue.

• USDA Hardiness Zones: Varies depending on species, typically 3-9
• Sun Requirements: Full sun to part shade
• Soil Conditions: Well-draining, moist, acidic for blue varieties
• Size: Varies greatly depending on species, from 3-15 feet tall
• Pollinators: Bees, butterflies
• Deer Resistance: Low (deer may eat it)

Bluebeard (Caryopteris x clandonensis)

This compact shrub is covered in clusters of small, fragrant blue flowers in late summer and early fall. It’s a magnet for pollinators and adds a splash of color to the garden when many other plants are starting to fade.

• USDA Hardiness Zones: 5-9
• Sun Requirements: Full sun
• Soil Conditions: Well-draining, average
• Size: 2-3 feet tall, 2-3 feet wide
• Pollinators: Bees, butterflies
• Deer Resistance: High (deer generally avoid it)

Rose of Sharon (Hibiscus syriacus)

While most varieties of Rose of Sharon have pink or white flowers, there are a few cultivars with beautiful blue blooms, such as ‘Blue Bird’ and ‘Azurri Satin’. These hardy shrubs are known for their long blooming period and adaptability to various soil conditions.

• USDA Hardiness Zones: 5-8
• Sun Requirements: Full sun
• Soil Conditions: Well-draining, average
• Size: 8-12 feet tall, 6-10 feet wide
• Pollinators: Bees, butterflies, hummingbirds
• Deer Resistance: Low to moderate (deer may nibble on it)

Tips for Growing Blue Flowers for Summer Blooms

To ensure your blue flowers thrive and continue to dazzle throughout the summer, follow these essential care tips.

Soil and Sunlight for Blue Flowers

Most blue flowers thrive in well-draining soil. However, specific varieties, like hydrangeas, prefer slightly acidic soil to maintain their vibrant blue hue.

Before planting, conduct a soil test to determine the pH level and nutrient content of your soil. This will help you make any necessary adjustments, such as adding amendments to achieve the ideal conditions for your chosen blue flowers. You can easily obtain soil test kits from your local cooperative extension or garden nursery.

Once you’ve prepared your soil, choose a planting location that receives the appropriate amount of sunlight for your selected varieties, ranging from full sun to shade. Read plant tags and descriptions carefully so you can cater to their specific needs.

Watering Blue Flowers for Summer

Regular watering is crucial for blue flowers, especially during the scorching summer months. However, overwatering can be just as detrimental as underwatering, leading to root rot and other problems.

The ideal watering frequency and amount depend on several factors:

• Plant type: Different flowers have varying water needs. Research the specific requirements of your chosen blue blooms.
• Soil type: Sandy soils drain faster than clay soils, requiring more frequent watering.
• Weather conditions: Hot, dry weather increases water evaporation, necessitating more frequent irrigation.
• Planting location: Plants in containers or exposed areas may dry out faster than those in shaded beds.

To ensure your blue flowers thrive, water deeply and less frequently. This encourages roots to grow deeper into the soil, making them more drought-tolerant. Allow the soil to dry slightly between waterings, but don’t let it become completely parched.

Watering Tips

• Water early in the day: This allows plants to absorb moisture before the midday heat intensifies, reducing water loss through evaporation.
• Water at the base: Direct water to the roots, avoiding the leaves, to prevent fungal diseases and other moisture-related issues.
• Consider drip irrigation or soaker hoses: These methods deliver water directly to the roots, ensuring efficient use and minimizing evaporation.

By monitoring your plants and adjusting your watering practices accordingly, you can maintain a healthy and vibrant blue flower display throughout the summer season.

Fertilizing Blue Flowers for Summer

A balanced slow release fertilizer and compost applied in spring will provide the nutrients necessary for healthy growth and abundant annual flowers. Follow the instructions on the fertilizer packaging for the correct application rate.

Perennials and shrubs do not need to be fertilized. Instead, focus on providing the plant with good-quality soil. Amend the soil with compost, and leaf mold, then top it off with some fresh mulch. Over-fertilization can lead to leggy growth, fewer blooms, and invite pest and disease problems. The only time I fertilize perennials is when they are planted in pots.

Deadheading

Regularly removing spent flowers encourages continued blooming and keeps your plants looking tidy. Simply pinch or snip off the faded flower heads just above a set of healthy leaves to keep your summer blooming blue flowers looking amazing.

Creative Ways to Incorporate Blue Flowers in Your Summer Garden

• Borders and Beds: Create stunning borders with a mix of blue flowering plants and complementary colors. Use taller varieties like delphiniums and agapanthus as focal points, and fill in with lower-growing plants like lobelia and bacopa.
• Containers: Utilize the versatility of blue flowers by planting them in pots and containers. This allows you to move them around to create focal points on patios, decks, and balconies.
• Cut Flower Arrangements: Don’t forget to bring the beauty of blue indoors! Many blue flowers, such as delphiniums and salvias, make stunning additions to cut flower arrangements.

Final Thoughts on the Best Blue Flowers for Summer

Blue flowers bring a sense of calm and balance to my summer garden. Their cool hues offer a refreshing contrast to the fiery oranges and sunny yellows, creating a sense of peace and tranquility amidst the vibrant summer palette. I’m captivated by their unique charm and the way they level up the overall aesthetic of my garden.

Whether you choose annuals, perennials, or shrubs, incorporating blue flowers into your landscape will add a touch of sophistication and elegance that is sure to delight you and your garden visitors alike.

So, why not embrace the beauty of blue this summer? With so many stunning varieties to choose from, you’re sure to find the perfect blue blooms to enhance your garden oasis. Let these serene flowers transport you to a place of tranquility and wonder, right in your own backyard.

For more information about growing blue flowers, check out this article from theUniversity of Florida Extension Service.

To drill down on more beginner gardening techniques and tips, please read these posts:

• Flower Gardening 101
• Growing a Cut Flower Garden for Beginners
• Container Garden Ideas for Beginners

If you have any questions, comments or suggestions, please let me know in the comments below. I’d love to hear! And feel free to share this post with anyone you think would find it helpful too.

Thank you for visiting the blog today!

Enjoy your day! xo

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