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Trees and Plants with Blue Flowers for Sale - Buying & Growing Guide

Do You Know Your Growing Zone? i Growing zones help determine if a particular plant is likely to grow well in a location. It identifies the average annual minimum winter temperatures across the U.S. provided as a map by the USDA.
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Trees and Plants with Blue Flowers – Buying & Growing Guide

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by Trees.com Staff – last update on Jan 5, 2020

Blue flowers are not considered exceptionally rare, but they are certainly one of the least commonly found flower colors in gardens, with blue flowers accounting for just ten percent of all flowering plants known in the world.

20 Types of Blue Flowers

1. Blue Star

Blue Star

Origin: North America

Name: Amsonia sp.

Family: Apocynaceae

Type: Perennial flowering shrub

Mature Size: 2-3 feet tall, and 2-3 feet wide

Hardiness Zone: USDA growing zones 5- 11

Light: Full sun to partial shade

Water: Keep moist, drought-tolerant once mature

Soil: Well-draining

Flower Color: Pale to medium blue

Special Features: Awarded the 2011 Perennial Plant of the Year

These pretty blue flowers grow in clusters, with star-shaped blooms that have a soft and delicate appeal. The green leaves are lance-shaped with a resemblance to willow leaves, which transform into gold in the fall. The flowers bloom for several weeks in the summer before turning to seed pods. They are native to North America and grow easily without many problems, offering a beautiful, low-maintenance blue flowering plant for warm climates. They will bloom best in full sun but can handle partial shade as well.


2. Bachelor’s Buttons

Blue Star

Origin: Europe

Name: Centaurea cyanus

Family: Asteraceae

Type: Annual wildflower

Mature Size: 1- 3 feet tall

Hardiness Zone: USDA growing zones 2- 11

Light: Full sun

Water: Medium moisture

Soil: Well-draining

Flower Color: Vivid bright blue

Special Features: Self sows easily

This pretty wildflower got its name because bachelors wore the flower on their lapel when they were courting. Some may also know this plant as the Cornflower because it grew in abundance among cornfields in Europe. It is now widely cultivated in home gardens thanks to its striking beauty, its low-maintenance, and its ability to survive in a wide range of climates. Bachelor’s buttons produce bright blue flowers that reach up to face the sun. The blooms themselves are a cross between daisies and thistle flowers. They self-seed easily, giving you plenty of new flowers each year.


3. Himalayan Blue Poppy

Himalayan Blue Poppy

Origin: Tibet

Name: Meconopsis betonicifolia

Family: Papaveraceae

Type: Perennial

Mature Size: 4 feet tall

Hardiness Zone: USDA growing zones 3- 9

Light: Partial shade

Water: Maintain moist soil

Soil: Rich, well-draining

Flower Color: Medium to light blue

Special Features: Uncommon, due to its difficulty level

If you have green fingers and like a challenge, then this is the flower for you. It can be tricky to grow, seeing as it is native to the mountains of Tibet and is accustomed to quite specific growing conditions. It likes to have consistently moist soil, shelter, and shade. It can be grown from seed, and if you achieve success, you will be rewarded with a striking large dainty looking blue flower, which, as you would expect from the name, greatly resembles a poppy. The foliage of the plant is quite different from that of a poppy, though, offering glossy green leaves (Royal Horticultural Society).


4. African Blue Lily

African Blue Lily

Origin: South Africa

Name: Agapanthus africanus

Family: Amaryllidaceae

Type: Perennial

Mature Size: 2 feet tall

Hardiness Zone: USDA growing zones 8- 11

Light: Full sun to partial shade

Water: Medium moisture

Soil: Rich, well-draining

Flower Color: Dark blue through to white

Special Features: Long blooming period

These trumpet style flowers grow in large clusters, varying in colorful shades of blue and white. They have a long blooming period, which makes them popular with gardeners, flowering from July through to September. Their main drawback is that they are quite tender and therefore are only suitable for growing in warm climates.


5. False Indigo

False Indigo

Origin: North America

Name: Baptisia australis

Family: Fabaceae

Type: Herbaceous perennial

Mature Size: 4 feet tall

Hardiness Zone: USDA growing zones 3 to 9

Light: Full sun to partial shade

Water: Dry to medium

Soil: Well-draining

Flower Color: Purple blue

Special Features: Used in making dye

This plant features upright branching stems from which plentiful violet-blue dainty flowers grow. It can be difficult to establish, but once strong roots have taken hold, it will become drought-tolerant. False Indigo does not like to be disturbed, so plant it in a spot where it can live out its life. Large clumps can be divided for propagation, though the plant can react badly to this.


6. Gentians

Gentians

Origin: Asia, Europe, Americas

Name: Gentiana sp.

Family: Gentianaceae

Type: Flowering plant

Mature Size: 3 inches tall

Hardiness Zone: USDA growing zones 4 to 8

Light: Full sun to partial shade

Water: Maintain moist soil

Soil: Rich, fertile soil

Flower Color: Vibrant medium blue

Special Features: Gentian root is used in making some drinks

These tubular flowers come in several shades, but predominantly they are blue. They typically prefer cool and wet conditions and are native to woodland areas, thriving well in rock gardens. The large, showy flowers have won the plant the prestigious Award of Garden Merit from the Royal Horticultural Society. Flowers typically bloom in fall to provide color and interest throughout the cooler months (BBC).


7. Lungwort

Lungwort

Origin: Europe

Name: Pulmonaria officinalis

Family: Boraginaceae

Type: Evergreen perennial

Mature Size: 12 inches tall

Hardiness Zone: USDA growing zones 2 to 8

Light: Shade

Water: Medium moisture

Soil: Rich, fertile soil

Flower Color: Pale to medium blue

Special Features: Shade-loving plant

This unusual plant blooms early, often hailing the start of spring. The flowers initially appear red or pink but develop to blue as they open up. The stems and leaves of the plant have tiny hairs and can be green or variegated with white spots. As shade-loving plants, these are brilliant for bringing color to darker corners of your garden where many flowers would not typically grow.


8. Corydalis China Blue

Corydalis China Blue

Origin: China

Name: Corydalis flexuosa

Family: Papaveraceae

Type: Perennial

Mature Size: 12 inches tall

Hardiness Zone: USDA growing zones 4 to 8

Light: Partial shade

Water: Medium moisture

Soil: Well-draining

Flower Color: Vibrant mid blue

Special Features: Early bloomer

This plant has a low-growing spreading habit that makes it ideal for use as groundcover or for filling in gaps in your garden. From early spring through to the middle of summer, it produces dainty tubular flowers in vivid shades of blue. It grows well under trees or alongside large shrubs where it can benefit from dappled shade (Gardeners World).


9. Periwinkle/ Creeping Myrtle

Periwinkle/ Creeping Myrtle

Origin: Europe

Name: Vinca minor

Family: Apocynaceae

Type: Evergreen

Mature Size: 4 inches tall

Hardiness Zone: USDA growing zones 4 to 8

Light: Partial shade

Water: Medium to low moisture

Soil: Well-draining

Flower Color: Pale blue

Special Features: Effective flowering groundcover

This plant has a rapid spreading habit, which makes it ideal for use as groundcover. This feature also makes it suitable for use as erosion control, a job which it fulfills very successfully in various areas across the US. The name periwinkle comes from the shade of periwinkle blue flowers that bloom on the plant in April and May. Once established, the plant is drought-tolerant and requires little in the way of care, though you will need to keep an eye on it to prevent it from taking over your garden.


10. Larkspur

Larkspur

Origin: Northern Hemisphere

Name: Delphinium

Family: Ranunculaceae

Type: Perennial or annual flowering plant

Mature Size: 6 feet tall

Hardiness Zone: USDA growing zones 3- 7

Light: Full sun to partial shade

Water: Medium moisture

Soil: Well-draining, fertile soil

Flower Color: Blue, pink, white, purple

Special Features: Make good cut flower arrangements

These showy plants, often known simply by their scientific name of Delphinium, grow in tall spikes from which summer flowers bloom in shades of pink, white, purple, and blue. They can be quite difficult to grow as they are sensitive to very hot summers, as well as adverse weather such as rain or strong winds. They prefer mild, cool summers, and thrive in moist conditions. Plant them alongside a fence or wall to help shelter them from wind and rain and stake them to prevent them from drooping over.

These flowers are popular in cut flower bouquets, and if you cut them early enough in the season, then you should find they will bloom again before the year is out. All parts of the plant are poisonous to both humans and animals and should be handled with caution (The Old Farmers Almanac).


11. Georgia Blue/ Speedwell

Georgia Blue/ Speedwell

Origin: North America

Name: Veronica umbrosa

Family: Plantaginaceae

Type: Semi-evergreen perennial

Mature Size: 4 inches tall

Hardiness Zone: USDA growing zones 4 to 8

Light: Full sun to partial shade

Water: Maintain moist soil

Soil: Well-draining

Flower Color: Medium blue

Special Features: Vigorous growth

This low-growing plant grows vigorously to a maximum height of just 4 inches, making it ideal for use as groundcover in an area you want to cover fairly quickly. The rooting stems are dotted with tiny blue flowers that have pretty, open faces, and they bloom for a long time throughout both spring and summer. Once the plant has covered enough ground, you can propagate it easily by division. It thrives in full sun but will also tolerate partial shade. It is attractive to butterflies and other pollinators, bringing a host of wildlife into the garden.


12. Black and Blue Sage

Black and Blue Sage

Origin: South America

Name: Salvia guaranitica

Family: Lamiaceae

Type: Perennial subshrub

Mature Size: Up to 5 feet tall

Hardiness Zone: USDA growing zones 7 to 10

Light: Full sun to partial shade

Water: Medium moisture

Soil: Well-draining

Flower Color: Vivid mid blue

Special Features: Unique contrasting black stems against blue flowers

This plant can be grown as a perennial in warmer climates or as an annual in zones lower than zone 7. It has a striking appearance, with dark green-black stems from which vibrant blue flowers grow. It is also commonly known as ‘Blue Anise Scented Sage’ because when crushed, the leaves emit an aroma resembling that of anise.

This plant is popular among gardeners because it grows easily, to the point that it has become invasive in some areas, so keep a close eye on it in your garden. The stunning flowers are the showstopper of this plant, blooming all through summer until the first frost.


13. Siberian Squill

Siberian Squill

Origin: Russia

Name: Scilla siberica

Family: Asparagaceae

Type: Flowering perennial plant

Mature Size: Up to 8 inches tall

Hardiness Zone: USDA growing zones 2 to 8

Light: Full sun to partial shade

Water: Medium moisture

Soil: Well-draining

Flower Color: Deep medium blue

Special Features: Self-seeding

In spite of its name, this plant does not hail from Siberia, instead originating in Russia, though it has become naturalized in the US. It grows pretty nodding bluebell-like flowers on upright stems, blooming early on in the spring. It spreads rapidly from seed, leading to it becoming invasive in some areas in the US. To prevent the plant from self-seeding in your garden, deadhead the flowers before they have a chance to become seeds. To encourage self-seeding, leave just a few flower heads intact to prevent your garden from becoming overrun with the plant.


14. Heavenly Blue

Heavenly Blue

Origin: East Asia

Name: Caryopteris x clandonensis

Family: Lamiaceae

Type: Deciduous shrub

Mature Size: 3 feet tall

Hardiness Zone: USDA growing zones 5 to 9

Light: Full sun

Water: Medium moisture

Soil: Well-draining

Flower Color: Deep blue

Special Features: Late bloomer

This shrub has a compact habit with both attractive foliage and flowers. Its leaves are toothed in a pale gray-green color, and its small flowers bloom in dark blue shades from late summer through to fall. This plant is mostly maintenance-free. However, it only produces flowers on new growth. Therefore, to ensure an abundantly flowering plant, you will need to cut it back to a few inches from the ground at the very beginning of spring.


15. Starflower

Starflower

Origin: Europe

Name: Borago officinalis

Family: Boraginaceae

Type: Annual or perennial

Mature Size: 3 feet tall

Hardiness Zone: USDA growing zones 2 to 11

Light: Full sun to part shade

Water: Low to medium moisture

Soil: Tolerates a range of soils

Flower Color: Bright blue and cream

Special Features: Edible and scented

This plant is actually a lesser-known herb that can be used in cooking. It has a taste and scent similar to a cucumber, but it is not widely cultivated for this purpose. The plant grows easily requiring very little care or maintenance and will self-seed if left to its own devices.

Both the foliage and the stems of the plant feature coarse hairs, which can become prickly as the plant gets older, but it is from these stems which the stunning star-shaped blue flowers are produced, so don’t be tempted to remove them. The flowers themselves also emit a cucumber-like scent, and bloom for an extended period throughout summer.


16. Love in a Mist

Love in a Mist

Origin: Europe, Asia, North Africa

Name: Nigella damascena

Family: Ranunculaceae

Type: Annual flowering plant

Mature Size: 1.5 feet tall

Hardiness Zone: USDA growing zones 2 to 11

Light: Full sun to partial shade

Water: Medium moisture

Soil: Rich well-draining soil

Flower Color: Mid blue

Special Features: Work well in bouquets

This dainty-looking plant produces star-shaped blue flowers above a fluffy bush of green foliage. The thread-like leaves are quite similar in looks to dill, with a delicate and gentle appearance. This plant prefers rich soil, though it will thrive in almost any soil type, even sandy, poor-quality soil. In its native habitat, it is often found in neglected areas of land which are wet or boggy.

It germinates easily from seed, though it does not respond well to being moved. The blue blooms persist all through summer and also work well in cut flower bouquets.


17. Desert Bluebell

Desert Bluebell

Origin: North America

Name: Phacelia campanularia

Family: Boraginaceae

Type: Annual

Mature Size: 2 feet tall

Hardiness Zone: USDA growing zones 7 to 10

Light: Full sun

Water: Drought-tolerant

Soil: Well-draining, sandy soil

Flower Color: Vibrant deep blue

Special Features: Drought-tolerant flowering plant

As suggested by their common name, these flowers are native to dry desert areas, namely those around California. True to form, these plants are drought-tolerant and work well among rock gardens or planted alongside succulents. The bell-shaped flowers are a striking blue, which can sometimes take on a flat or funnel-like appearance. Grow them in sandy soil and avoid overwatering.


18. Birdbill Dayflower

Birdbill Dayflower

Origin: North America

Name: Commelina dianthifolia

Family: Commelinaceae

Type: Perennial herb

Mature Size: 8 inches tall

Hardiness Zone: USDA growing zones 7 to 10

Light: Full sun to partial shade

Water: Medium moisture

Soil: Well-draining

Flower Color: Deep mid blue

Special Features: Flowers last just a day

This plant works best at the front of a border or in a container. It produces one flower at a time, and as its name suggests, each flower lasts just one day, though it will be replaced with a brand new flower the very next day. The striking blue flowers measure approximately one inch across and are a delight to witness. Germination of these plants can take some patience, but once mature, the plants are quite hardy and will withstand a variety of adverse weather conditions.


19. Lobelia

Lobelia

Origin: North America

Name: Lobelia

Family: Campanulaceae

Type: Annual

Mature Size: 5 inches tall

Hardiness Zone: USDA growing zones 4 to 9

Light: Full sun

Water: Maintain moist soil

Soil: Well-draining

Flower Color: Deep blue

Special Features: Long blooming period

There are hundreds of varieties of Lobelia in numerous flowering colors, but the most commonly found flower color of this plant is a deep vibrant blue. It grows easily, producing an abundance of beautiful blooms seemingly with ease, making it a favorite among gardeners. An added bonus is that flowers last for an extended time period, appearing in July and lasting through to October. Most varieties of this plant have compact habits, and it is uncommon for them to grow more than 5 inches tall. Their dainty stature makes them ideal for borders, beds, and container-planting (Lady Bird Johnson Wildflower Center).


20. Columbine

Columbine

Origin: Northern hemisphere

Name: Aquilegia

Family: Ranunculaceae

Type: Perennial

Mature Size: 20 inches tall

Hardiness Zone: USDA growing zones 3 to 8

Light: Full sun to partial shade

Water: Maintain moist soil

Soil: Well-draining

Flower Color: Purple blue

Special Features: Attractive to butterflies

These early bloomers flower in springtime along with deep green foliage that transforms into a dark red in the fall. The pretty funnel-shaped flowers have nodding heads and can appear in numerous colors, though most notably blue. They thrive in moist conditions and should not be allowed to dry out, even in winter. Mulch over the soil to help prevent moisture from evaporating.