Best Blue Annual Flowers to Grow in your Garden

Surround yourself with the color of the sky, especially if you spend much of your time indoors. Blue is often associated with tranquility and relaxation, making it a popular choice for high-stress environments like hospitals and waiting rooms. By incorporating blue flowering plants into your outdoor space, you not only invite natural beauty but also create a peaceful oasis where you can unwind and recharge. 

In this blog, you’ll learn about the most popular blue annual flowers, how to grow them, where they thrive, and other essential facts to help you decide if they’re the right fit for your garden. Let’s get started!

1. Bachelor’s Button (Centaurea cyanus)

Bachelor’s Button is an annual plant with true blue flowers that appear in early summer and last until late summer. The flower heads are round and fringed, with delicate petals forming a small, fluffy crown atop tall, slender stems. It prefers full sun and is hardy in USDA zones 2-11, thriving in most temperate gardens. Centaurea cyanus attracts pollinators and is an excellent cut flower; it is sometimes used to create natural blue dyes.

 

2. Blue Sage (Salvia azurea)

Blue Sage is an herbaceous annual with tall stems that bear spikes of tubular, deep blue flowers from mid-summer to early fall. Native to the central United States and hardy in USDA zones 5-9, it grows best in full sun and tolerates drought conditions once established. While Salvia azurea is primarily used as a cut flower, it is often incorporated into xeriscaping or low-water gardens and can also be used in herbal remedies and teas.

 

3. Baby Blue Eyes (Nemophila menziesii)

Baby Blue Eyes is a low-growing annual flower with sky-blue, cup-shaped blooms that appear in early spring. Its soft, fern-like foliage provides a lush green base for the delicate flowers, which are edged with white and grow to around 6 inches tall. Native to California, it thrives in part shade or full sun in cooler climates and prefers moist, well-drained soil. Hardy in USDA zones 5-10, is an excellent choice for rock gardens, container edges, or ground cover. 

4. Trailing Lobelia (Lobelia erinus)

Trailing Lobelia is a compact, spreading annual that produces masses of small, vibrant blue flowers from early spring to late summer. The flowers are typically bright blue with a white eye at the center and are usually displayed in hanging baskets, window boxes, or as edging plants in garden beds. Native to South Africa, Lobelia thrives in partial shade to full sun, prefers morning sun and afternoon shade in hot regions, and is hardy in USDA zones 10-11.

5. California Bluebell (Phacelia campanularia)

California Bluebell is an annual herb known for its intense blue, bell-shaped flowers that bloom from late spring through early summer. Native to the deserts of California, this plant is drought-tolerant and thrives in full sun, hardy in USDA zones 6-10. It is a popular pollinator and, while it doesn’t climb, it spreads, which means it can be used as ground cover for many landscaping designs.

6. Blue Daze (Evolvulus glomeratus)

Blue Daze also known as "Shaggy dwarf morning-glory" is a low-growing, spreading annual with silvery-green foliage and small, bright blue, funnel-shaped flowers that bloom from early summer to the end of the season. Native to South America, Blue Daze thrives in full sun and is hardy in USDA zones 9-11. The plant remains evergreen in warm climates and works well in garden beds, hanging baskets, or ground cover. It can also withstand coastal conditions.

7. Heavenly Blue Morning Glory (Ipomoea tricolor)

Heavenly Blue Morning Glory is a climbing annual vine known for its large, trumpet-shaped, sky-blue flowers with white throats. Blooming from mid-summer to early fall, it blooms in the morning and closes by afternoon. As a climbing flower, the vine can grow up to 10 feet tall and can be trained on trellises, fences, or arbors, making it useful for creating privacy screens. Native to tropical regions of Central and South America, it loves full sun and thrives in USDA zones 2-11.

8. Blue Lady (Browallia americana)

An annual flowering plant known for its vibrant blue to violet blooms that last from early summer until the first frost, Blue Lady (Browallia americana) is native to tropical regions of Central and South America. It thrives in full sun to partial shade and is suitable for USDA zones 10-11, where it is considered a short-lived perennial; otherwise, it is an annual. Blue Lady is a climber, reaching heights of 12 to 18 inches, and is commonly used in gardens as a privacy screen and as a pollinator magnet.

9. Floss Flower (Ageratum houstonianum)

Floss Flower is an annual that produces clusters of fluffy, powder-blue flowers on compact plants. Blooming from late spring through early fall, it prefers full sun to partial shade and moist, well-drained soil. Native to Mexico and Central America, it is hardy in USDA zones 2-11 and works well in flower beds, borders, or as a container plant. Ageratum is commonly used as a bedding plant because of its long-lasting blooms, cut flower potential, and ability to attract pollinators.

10. Blue Salvia (Salvia farinacea)

Blue Salvia is an annual plant known for its striking spikes of tubular blue flowers and a long blooming period that lasts from late spring until the first frost. This plant thrives in full sun to partial shade and is hardy in USDA zones 8-10. Additionally, Blue Salvia attracts pollinators and serves as a popular cut flower, while its tendency to spread makes it a suitable choice for ground cover.

11. Siberian Squill (Scilla siberica)

Siberian Squill is a perennial known for its delicate clusters of small, star-shaped periwinkle blue flowers that bloom in early spring. It thrives in part sun to full shade and is hardy in USDA zones 3-8. Siberian Squill is favored for two reasons: it is low maintenance and grows as ground cover, spreading over time to create a meadow-like carpet of blue in spring.

 

Final Thoughts

As mentioned before, blue is associated with calm and peace, so adding it to your gardening chores creates an environment where you can clear your head. By planting annuals, you experiment and see which plants thrive and which ones you want to replace in the next season.