The color blue is overwhelmingly chosen as the most popular color by both men and women, so it is no wonder that we are drawn to blue flowers. Blue is a soothing color that evokes feelings of calm, trust, honesty and loyalty. Blue flowers add a touch of tranquility and cool elegance to the garden. They make excellent bedfellows in the garden, blending and complementing other hues. I love combining blue flowers with violet, pink and white hues and silver foliage in a sunny summer border, or juxtaposing them with bright yellows and oranges for a dynamic “pop” in the spring garden.
Since they are less prevalent than white, pink and yellow flowers, blue flowers appeal to all gardeners. Here are some of my favorite blue perennials for Zone 5-6 gardens:
1. Aconitum ‘Arendsii’
Blue flowers are particularly rare in autumn, and the deep indigo-blue flowers of Monkshood punctuate the oranges and golds of this season.
3-4’ tall, part shade, blooms September-October
Also known as False Indigo, this late emerging, statuesque perennial with spires of pea-like flowers and handsome blue-green foliage is a focal point in the perennial bed.
3-4’ tall, sun to part shade, blooms May-June
3. Centaurea montana
This perennial bachelor button is a cottage garden favorite, with furry gray-green leaves similar to lamb’s ears, and large, brilliant blue flowers.
12-18” high, full sun, blooms in May
Related post: Centaurea Montana: A Cottage Garden Favorite
4. Geranium ‘Rozanne’ or ‘Johnson’s Blue’
Perennial geraniums with their delicately cut foliage and low spreading habit are beautiful companions to tall, upright perennials, roses and shrubs.
Rozanne: 24” tall, full sun, blooms June-frost
Johnson’s Blue: 20” tall, full sun to part shade, blooms late May-June
Related post: Geraniums: Delicate Beauty for the Perennial Garden
5. Pulmonaria ‘Trevi Fountain’
One of the earliest flowers to bloom in spring, pulmonaria sports showy, lance-shaped leaves with silver spots, and deep blue flowers that change to violet and rose as they age.
11” tall, part shade, blooms in April
Related post: Pulmonaria Pops in the Shade
6. Lobelia siphilitica
Spires of brilliant blue, trumpet-shaped flowers on a perennial that gently seeds itself in the garden.
24” tall, part shade, mid to late summer
8. Nepeta ‘Walker’s Low’
This catmint sports compact mounds of aromatic gray-green foliage with lavender-blue flowers.
10” tall, sun to part shade, blooms from late spring until fall
10. Platycodon ‘Fuji Blue’
With irresistible balloon-like buds that open to bright-blue, five lobed flowers, Balloon Flower is a late-emerging perennial that blooms in late summer.
20” tall, full sun, blooms July-August