Blue flowers? If that's your favorite shade, these blooms that will suit your landscape (2024)

What’s your favorite color? My favorite color has always been green. I guess it figures, given my life-long interest in plants. But, if you ask me what my favorite color of flower is, I would say blue. Although there are green flowers, like most people, I tend to look at them as more of a curiosity than something I want to fill my garden with.

Blue, particularly true blue, is a color relatively rare among garden flowers. Blame the pollinators. Flowers, remember, are not produced for our enjoyment. The colors of the petals are based on attracting pollinating insects or birds to visit the flowers and help with cross-pollination. Apparently, blue is not too attractive to most insects and birds.

First, let me say that when gardeners use the word “blue” to describe the color of flowers, we sometimes fudge a bit. There is often a decidedly lavender or purplish tint to flowers we call blue. As a result, we often use the terms “true blue” or “sky blue” when describing flowers that are actually blue.

A number of plants with blue flowers are in bloom now. Some of these are wildflowers you may see blooming along the roadside or in area gardens now and over the next month or so.

Our native lyreleaf sage (Salvia lyrata) produces a low rosette of leaves, often colored with vivid purple, and an 8-inch-tall spike of lovely, light blue flowers. They are blooming now along roads and highways and in area parks. There are some cultivated salvias that produce true blue flowers — notably bog sage (Salvia uliginosa) and Argentine Skies salvia (Salvia guaranitica ‘Argentine Skies’), and many salvias that produce lavender-blue or purple-tinted blue flowers.

Another wildflower blooming now is spiderwort (Tradescantia virginiana) with triangular-shaped flowers in shades of lavender-blue (occasionally purple, rosy or pink). There are garden varieties of spiderwort, often with larger flowers and more robust growth. But the lovely wild forms blooming now are also nice. They are well adapted to damp areas or average garden beds.

Other blue wildflowers you may see blooming in the wild or in gardens in spring or early summer include stokesia (Stokesia laevis). This is a great garden perennial for our area with lavender-blue double daisy flowers. Wild indigo (Baptisia australis) is tough and durable for sunny areas and deserves much more use in southeast Louisiana gardens. And blue-eyed grass (Sisyrinchium angustifolium) is one of my favorites.

Chicory (Cichorium intybus) is grown in the cool-season vegetable garden as a salad green with a slightly bitter flavor (the roasted roots are ground and used in coffee). What I love most about it, however, are the masses of one-inch true blue flowers produced in spring and early summer. I grow it for its flowers.

There are several cool-season bedding plants that produce blue flowers, including a number of pansy (Viola x wittrockiana) and viola (Viola cornuta) varieties that produce light to medium blue flowers with or without faces.

And blue spring-flowering, cool-season bedding plants must include columbine varieties (Aquilegia) that produce heavenly sky blue flowers and delphiniums (Delphinium hybrids) like Diamonds Blue. Although you may see columbines and delphiniums blooming beautifully now, it’s late to plant these as they prefer to grow during cool weather.

Two other cool-season bedding plants blooming now are annual lobelia (Lobelia erinus) and forget-me-nots (Myosotis sylvatica). They are excellent for adding blue to the cool-season garden. Lobelia is low-growing, forming a mound or mat. The plants literally cover themselves with flowers of various shades of blue from cobalt to sky blue. Flowering continues until it gets hot in late May/early June. The sky-blue flowers of forget-me-nots are delicate but so beautiful. Plant transplants now or seeds fall to late winter.

There are wonderful perennials with blue flowers that bloom in spring and summer. Blooming now are Louisiana irises that produce large, attractive flowers in many shades of blue.

Ajuga is a nice, low, spreading ground cover for small areas. Caitlin’s Giant ajuga is my favorite, with spikes of cobalt blue flowers about 6 inches tall blooming in late spring. A vining ground cover, periwinkle (Vinca major), is blooming now with star-shaped flowers of periwinkle blue. Blue star (Amsonia tabernaemontana) blooms with clusters of light blue, star-shaped flowers on stems 18 to 24 inches tall in early summer.

During May, blue-flowered hydrangeas (Hydrangea macrophylla) and lily-of-the-Nile (Agapanthus hybrids) are a delight. For blue hydrangeas, treat your plants with aluminum sulfate in March and October each year. Agapanthus comes in a variety of shades of blue, from light sky-blue to navy blue (as well as white).

And during the scorching heat of summer, nothing cools us down like the true-blue flowers of plumbago (Plumbago auriculata). Its large clusters of light to medium blue flowers (Imperial Blue is a darker blue variety) and long blooming season make it among our very best blue flowers.

Blue daze (Evolvulus) is a summer bedding plant that produces multitudes of three-quarter inch blue flowers on a low mounding plant. Blue daze is an LSU AgCenter Super Plants selection, and Blue My Mind is an especially nice variety.

Finally, a lovely summer-flowering small tree called vitex or chaste tree (Vitex agnus-castus) is especially beautiful. It’s tough as nails and drought resistant. Abundant spikes of lavender-blue flowers are produced on a 15-foot-tall tree in June and again in August.