Who doesn’t love the intense blue flowers of grape hyacinth in spring or the massive sky-blue flowers of hydrangeas in the summer? These blue hues are cropping up everywhere, even in health drinks – like the Butterfly pea teas. Butterfly pea (Clitoria) is a fast-growing tropical vine with vibrant blue flowers, but there are many other blue-flowering plants that perform well in Iowa and other Midwestern landscapes.
Spring Perennials | Summer & Fall Perennials | Groundcovers & Vines | Bulbs & Annuals | More Information
Blue pigment in plants
True blue is a rare pigment in nature. Delphinidin is the primary pigment responsible for blue in plant flowers. It is not a coincidence that it was named after Delphinium, where it was first found. This pigment is a type of anthocyanin or flavonoid. For the “true-blue” pigment to appear in flowers, several factors must work together. The pigment must be created in the right internal environment (often in an alkaline environment in complexes with flavones or certain metals). Delphinidin must also exist at high enough concentrations for the intense blue coloration to appear in petals. And this pigment is often associated with other pigments to increase its stability and expression in plants. When everything aligns properly, we are gifted with the sky-blue colors of Himalayan blue poppies (Meconopsis) or deep blue colors of Delphinium (Delphinium).
Perennials with Blue flowers
There are many perennials that are noted for their blue flowers. The pale blue flowers of natives like Virginia bluebells and woodland phlox are impressive in mass in Iowa woodlands in spring. Other perennials, such as delphiniums, lupines, and gentians, are noted for their deep blue flowers in summer.
Spring Blooming Perennials with Blue Flowers
Some of our favorite blue flowers are native woodland wildflowers. Virginia bluebells (Mertensia virginica) is a native woodland perennial with nodding clusters of pink buds that open to light blue, trumpet-shaped flowers. Growing 1 to 2 feet tall, it dies back by early summer and works well planted among slower-growing perennials or in naturalized areas.
Woodland phlox (Phlox divaricata) is a native plant that forms patches in moist, shaded woods, growing 12 to 15 inches tall with blue to lavender flowers in April and May. It performs best in partial shade and moist soils, making it well-suited for borders or naturalized woodland plantings.
Find many more spring blooms in blue in this article:
What spring-blooming perennials have blue flowers?
Summer & Fall Blooming Perennials with Blue Flowers
Beardtongue (Penstemon species) cultivars like ‘Electric Blue’ or ‘Heavenly Blue’ are great blue accents in the summer landscape. Several Aster (Symphyotrichum) species, hybrids, and selections are noted for blue and blue/lavender blooms. Look for cultivars like ‘Bluebird’, ‘Blue Bayou’, ‘October Skies’, and ‘Raydon’s Favorite’ for blue flowers into fall.
Find more blue blooms for summer in this article:
What summer- and fall-blooming perennials have blue flowers?
Groundcovers & Vines with Blue Flowers
A few other blue flowers to consider are groundcovers like bugleweed (Ajuga) and Vinca (Vinca) for spring blooms and Plumbago (Ceratostigma) for late summer blooms.
Clematis should also be considered for blue flowers. Several species, such as Clematis durandii, C. integrifolia, and C. macropetala, are noted for their striking lavender-blue flowers. Clematis cultivars like ‘Multi Blue’, Blue Light®, ‘H.F. Young’, ‘Lindsay’, and ‘Romona’ are a few of the available blue bloomers.
Bulbs & Annuals with Blue Flowers
Many bulbs like hyacinth, grape hyacinth, and squill, are noted for blue flowers in spring. The blue flowers of heirloom annuals like forget-me-not and morning glory were probably grown by your grandparents or great-grandparents (and are still grown today).
Find more bulbs and annuals with blue flowers in these articles:
What annuals have blue flowers?
More Information
- Native Woodland Wildflowers for the Home Garden
- Early Spring Blooming Perennials
- Perennials for Sun
- Perennials for Shade
- Perennials for Shady Areas
- Flowering Plants for the Late Summer Garden
- Groundcovers for Shade
- Groundcovers for Sun
- Selecting and Planting Spring-Blooming Bulbs
- May Blooming Perennials
References: Basics of blue flower coloration; The Book of Blue Flowers by Robert Geneve. 2000. Timber Press
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