“I love blue more than any other color. I am inordinately attracted to any blue substance: to minerals like turquoise and lapis lazuli, to sapphires and aquamarines . . . and to a blue flower whether or not it has any other merit.”
—ELEANOR PERENYI
The great American garden writer Eleanor Perenyi expressed what we all feel, that blue is a very appealing color. It is the most popular color in the world. Although most flowers come in hues of yellow, orange, red, and purple, there are relatively few blue flowers. Why? There is no true blue pigment in plants. The plants actually alter red anthocyanin pigments to make blue. These modifications, made naturally by the plants, combine with reflected light to create shades of blue. And so we have glorious blue flowers such as delphiniums, globe thistles, ageratums, irises, agapanthus, morning glories, and cornflowers, among others.
Not all blues are true blue. Often, what appears to be purple or violet flowers are labeled as blue. Blue-purple is a more common flower color than a clear blue. For this reason, we accept purple into the blue flower mix.
If true blue flowers are your goal, try deer-resistant gentian ‘True Blue’ (Gentiana ‘True Blue’). Another perennial that has vivid blue flowers is ‘Crater Lake Blue’ speedwell (Veronica austriaca ‘Crater Lake Blue’). Its much shorter cousin, ‘Georgia Blue’ creeping speedwell (Veronica peduncularis ‘Georgia Blue’), is a low-growing, evergreen ground cover with rich blue flowers in early to late spring. And there is the tender perennial ‘Blue My Mind’ dwarf morning glory (Evolvulus ‘Blue My Mind’), with nonstop, bright blue flowers that cover a spreading, silvery green plant. Grown as an annual and flowering from late spring until frost, it is great in planters. It is suitable for USDA hardiness zones 9–11.
To help blue flowers stand out, plant them in a large group. This works well because blue is a recessive color. In other words, unlike bold red, yellow, or white flowers, blue flowers need to be in front or in a large grouping to be noticed. An effective way to mass blue-purple flowers is to plant a wide swath of them winding through a flower bed or ground cover bed. Try curving a wide line of annual or perennial blue salvia. This “river of blue” directs the eye in a most dramatic way.
The Himalayan blue poppy (Meconopsis betonicifolia) is known for its large, silky, sky-blue flowers. The variety shown is Meconopsis Lingholm, a perennial that has rich blue flowers up to 4 inches wide on 3-foot-high stalks and blooms from late spring to early summer. The blue poppy derives its blue color from the pigment delphinidin, which also gives blue hues to Viola and Delphinium. It does best in a rich soil that does not dry out. I took this photo at the Rhododendron Species Botanical Garden in Federal Way, Washington, which has a delightful Meconopsis Meadow containing several hundred specimens! Zones 3–9.
Tradescantia ‘Blue & Gold,’ commonly known as ‘Blue & Gold’ spiderwort or ‘Sweet Kate,’ is a remarkable perennial. It has bright chartreuse-yellow grassy foliage, bejeweled with rich gentian-blue triangular flowers. It will flower all summer if old blooms are removed. It is easy to grow in many soil types, even wet sites. Attractive to butterflies. Full sun to partial shade. Zones 3–9.
The genus Salvia includes some of the clearest blue blossoms. The annual mealycup sage (Salvia farinacea) is a true performer in the summer and fall garden with strong upright flower spikes. Here, the cultivar ‘Victoria Blue’ (Salvia farinacea ‘Victoria Blue’) blooms in a corner planting bed. The blue color becomes deeper in cool weather, as shown here. Seldom damaged by deer. Photo by Laura Hendrix McKillop.
The beautiful sky-blue flowers of trailing annual lobelia (Lobelia erinus), shown here in a planter set atop a tree stump chair, is a standout.
As you walk across the Bridge of Flowers, you can catch a glimpse of the Deerfield River beyond the gorgeous array of annual and perennial blooms. This photo was taken in early July when the seed heads of ornamental onion (Allium spp.) stand above the purple spikes of gayfeather (Liatris spicata), red poppies, and the small white blossoms of feverfew (Tanacetum parthenium). Photo by Michele Fitzgerald.