Most so-called blue plants are actually purple. Are true blue plants really rare? One list from a google search lists 7 true blue flowers. Another list claims 12, another list claims 20, and another one claims 61. Many of the plants from the 61-flower list are purple. For the collector or average gardener, this is confusing. It is very disappointing to order a plant and expect it to be true blue and getting purple flowers. I’ve been working on a true-blue flower list for years and this is the result. This is an easy way to organize types of true-blue flowers, I’ve organized the plants into 4 groups, annual plants, ground covers, perennials, and shrubs.
Annual plants
The first category of true-blue flowers are annuals which only last one season, but WOW do they bloom! From spring until almost fall you will get nonstop blooms for flower arrangements or just to enjoy in your garden.
(1)
Anagallis monellii has bright blue gentian blue flowers with a pink eye. It is drought-tolerant and self-sows.
(2) Anchusa caponsis Blue Angel has dark blue flowers and self-sows.
(3)
Centaurea cyanus Blue Diadem are tall 3′ bachelor buttons that bloom spring and summer and self-sows.
(4)
Cynoglossum amabile Blue Showers or annual Chinese forget -me- nots have bright sky-blue flowers and grows 3′.
(5) Evolvulus pilosus Blue Daze is a fun variety with larger blue flowers than older varieties. It grows 1′ high and 2 ‘wide.
(6) Ipomea tricolor Heavenly Blue or morning glories are very popular annual vining plants. The azure blue trumpet-shaped flowers open in the morning and close in the afternoon.
(7) Impatiens namchabarwensis or blue diamond impatiens, has ultramarine blue blooms and is relatively rare. It needs some shade and prefers cool summers.
(8) Lobelia erinus Fountain Blue is a favorite plant for baskets and window boxes and has bright blue blooms.
(9) Lathyrus sativus Azureus is a rare, sweet pea with luminous blue flowers tinged with pink. Seeds of this plant were actually found in King Tut’s tomb!
(10)
Nigella damascenes is a popular bushy annual with pale blue flowers and feathery foliage.
(11)
Nemophila menziesii Baby Blue Eyes is a native California wildflower. The flowers are a clear spring sky blue.
(12) Phacelia campanularia is another plant from California with intense gentian bluebell flowers on red stems.
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Groundcovers
Groundcovers are plants that spread, and hopefully crowd out weeds.
(13) 
Brunner macrophylla has intense blue flowers for shade and is fast growing.
(14) 
Chinodoxa forbesii or snow glories multiply annually and can take full sun or full shade.
(15 ) Ceratostigma plumbaginoides has true blue flowers from mid-summer to mid-fall. It needs afternoon shade.
(16) 
Globularia cordifolia makes a low mat of evergreen leaves with light blue powder puff flowers.
(17) 
Hyacinthoides non-scripta are classic English bluebells that boom in spring for about 4 weeks. They look great under trees.
(18) Isotoma fluviatilis can be used as a lawn alternative for a sunny area. The soft blue starry flowers bloom all summer. It is also called Laurentia axillaris.
(19) Lithodora diffusa Grace Ward makes a dark evergreen mat and has blue starry flowers from late spring to summer.
(20) Pratia pedunculate is a tough groundcover and forms a lush mat with true blue flowers.
(21) 
Veronica peduncularis Georgia Blue makes a short 6″ evergreen ground cover with blue flowers that have white eyes.
Perennials
Perennials are plants that live for more than 2 years. They typically hibernate in the winter and start growing again in the spring.
(22) 
Aquilegia coerulea Blue Star, also known as Rocky Mountain Columbine, is a delicate blue and white spring flower.
(23) Anemone coronaria Lord Lieutenant is a cup-shaped dark blue flower that blooms at the same time as daffodils.
(24) Allium azureum has round azure blue blooms in summer and is used in flower arrangements.
(25) 
Agapanthus SummerLove has grassy foliage and medium blue blooms. These south African bulbs need to be lifted and stored in cold climates.
(26) 
Corydalis flexuosa Porcelain Blue has unbelievably bright turquoise blue blooms. It needs shade and plenty of water.
(27) 
Delphinium alatum Sunny Skies are very large plants growing 6′ x 4′ and have amazing sky-blue blooms.
(28) Dracocephalum argunense Fuji Blue has blue helmet-shaped flowers and needle-like foliage.
(29) 
Eryngium alpinum is a very blue spikey drought tolerant perennial that can grow to 3′.
(30) 
Echinops bannaticus Blue Glow has intense blue globe-shaped flowers and grows to 4′.
(31) 
Felicia aethiopica Tight and Tidy is sometimes called the blue marguerite daisy, it is only hardy in southern states but can be planted as an annual in northern states.
(32) Globularia trichosantha is known as the blue globe daisy and has cobalt blue round blooms.
(33) 
Gentiana acaulis has true blue sapphire blooms. These are garden treasures.
(34) 
Iris, including Raindance Returns. Victoria Falls, and Open Ocean are all rebloomers and very blue.
(35) 
Ixia viviflora is a South African bulb that has TURQUOISE GREEN blooms with a purple center. A stunning and rare plant.
(36) 
Linum lewisii Blue Flax needs dry lean soil and has pale blue to dark blue flowers.
(37 
Lachenalia viridiflora has TURQUOISE flowers. It is another amazing plant from South Africa. It is simply gorgeous.
(38) 
Mertensia virginica, also known as Virginia bluebells, have pretty pink buds that open to blue bell-shaped flowers in the spring.
(39) 
Muscari armeniacum has fat cobalt blue bells that grow in the sun or shade.
(40) 
Myositis palustris is a perennial forget me not that forms dense mats of baby blue flowers in late spring.
(41) 
Meconopsis betonicifolia is at the top of everyone’s true blue flower list. The blue Himalayan poppy is notoriously difficult to grow, needing consistently moist, rich, and cool soil.
(42) 
Pulmonaria Twinkle Toes. Pink buds open to periwinkle blue flowers in spring. It needs afternoon shade.
(43) Puschinia libanotica has pale blue star-shaped florets with deep blue veining, It is often called Striped Squill.
(44) Penstemon heterophyllus Blue Springs produces bright blue flowers and flourishes in dry gardens and containers.
(45) Puya alpestris Sapphire Tower from Chili looks like an alien plant! It has metallic deep TURQUOISE blooms with orange anthers. It is only hardy to 15 degrees.
(46 ) Salvia is a group of plants that can have true blue flowers, Salvia patens has bright royal blue flowers.
(47) 
Scilla siberica is a low-growing bulb that has sparkling blue blooms in spring.
(48) 
Sisyrinchium angustifolium or blue-eyed grass has sky-blue flowers with a yellow eye. This grassy perennial will grow in sun or shade and dry or wet soils.
(49) 
Strongylodon macrobotrys is a SEAGREEN TURQUOISE tropical plant that you have to see to believe. It can grow 18 meters and is from the Philippines, Even the seeds of this plant are rare.
(50) Veronica armena has deep green needle-like foliage and small bright blue flowers.
Shrubs
Shrubs give height to the garden and provide shelter for birds and other wildlife.
(51) 
Aster laevis Bluebird can grow 4′ tall and blooms in fall. Rich soils will provide taller plants.
(52)
Amsonia x Blue Ice is a shorter version of Amsonia and has a short blooming time from late spring to summer.
(53) Ceanothus thyrsiflorus var. repens is a California native plant that can grow as far north as zone 7. It grows 2-3′ tall and 6-10′ wide. Clusters of fluffy sky-blue flowers cover the plant from spring to summer. It is also drought-tolerant.
(54) Clerodendron ugandense is often called the blue butterfly bush because the blue flowers look like butterflies
(55 ) Caryopteris x clandonensis Longwood Blue has sky-blue flowers and grows into a 3′ shrub.
(56) Dichroa febrifuga can grow to 7′ tall. In acidic soils, the blooms are blue while in alkaline soils, the blooms are purple, and pink.
(57) Echium fastuosum Eddie’s Blue is another California shrub that can grow 6′ x 6′. It is very drought-tolerant.
(58) 
Hydrangeas are the most popular blue-flowered shrub. There are many varieties from 3′ to 10′ tall. Most must be grown in acidic soils to get blue flowers. Alkaline soils will usually produce pink flowers.
(59) Tweedia caerulea Heaven Born has sky-blue star-shaped flowers and is hardy in zones 8-11.
Conclusion
Although the genetic makeup of plants somewhat determines flower color, environmental factors and micro-climates are important considerations. This list of 59 true blue flowers is not the final list as new varieties of plants are added to the market yearly. Please leave comments and let me know what your favorite true blue flower is, Do you have any blue flowers, not on the list?
terri@dramaticgardens.com