Although the word blue is sometimes used to describe sadness, blue also has many positive connotations, being a symbol of fidelity, faithfulness and spirituality. In the garden, blue imparts serenity and expansiveness. Blue in the plant world is elusive, however; finding flowers in the right shades can be tricky. Many blooms which are described as being blue or which have the word "blue" in their names tend toward a purplish-blue violet, while others are more in the reddish-blue or magenta range. Catalog photographs of blue flowers are notoriously deceiving, so it is helpful to view a blue-flowered plant in person before adding it to your garden.
Here is a plant listing, by no means conclusive, which you can use to capture some of the many shades of blue for your garden. If you have a favorite blue plant in your yard, please share with our readers!
Ageratum is a reliable source of blue in summer beds or containers. The fuzzy flower panicles are a soft powdery blue, and are useful for providing contrast for the more commonly found pink, yellow or white annuals. The dainty forget-me-not, or Myosotis, has sky-blue flowers set with a yellow eye. Calibrachoa, also called million bells, comes in both light and dark blue shades and is often used in summertime hanging baskets. The deep, electric blue Lobelia is another good container and hanging basket brightener. Centaurea or bachelor's button, an old-fashioned cottage garden favorite, never fails to delight with its true-blue color, and is easily grown from seed. Its other nickname, cornflower, has even become a color name.
Irises, both the Siberian and Japanese types as well as the bearded varieties, offer many shades of blue, from pale to deep, early in the summer. Veronica (sometimes called speedwell) plants can be ground-hugging, like the periwinkle-colored 'Waterperry Blue,' or upright and clump-forming. 'Crater Lake Blue' and 'Sunny Border Blue' are just two of the reliable summer-blooming blue-flowered veronicas. Campanula carpatica, or Carpathian bellflower, is also known for its bright blue bell-shaped flowers in varieties such as 'Blue Clips' and 'Pearl Deep Blue.' If you wish to have a blue flower for the back of the border, look no further than the stately Delphinium. Its tall spikes of bloom can be found in many different shades and intensities of blue. Aconiutum, or monkshood, is another tall blue bloomer with varieties which flower from late summer to late autumn, offering medium blue, blue and white, and deep navy-colored flowers.
Iris 'Blue Kentucky Girl'
Veronica 'Sunny Border Blue'
Delphinium elatum 'Blue Bird'
Aconitum carmichaelii 'Arendsii'
Blue-flowered spring bulbs abound. Chionodoxa or glory-of-the-snow, so named because its very early bloom time may leave it peeking from the snow, comes in blue or blue and white. Muscari, or grape hyacinths, and tiny scilla, or Siberian squill, are available in an intense royal blue shade which provides a good foil for pink tulips and golden daffodils. Fragrant hyacinth, blooming a little later in spring, can be found in a Dutch blue shade as well as a deeper purple-blue. The blue-tinted globes of allium flowers keeps the cool color theme going into summer.
Chionodoxa forbesii 'Blue Giant'
Scilla siberica 'Spring Beauty'
Hyacinthus orientalis 'Blue Ice'
Everyone knows the annual morning glory vine, and probably the best-loved of all is the true-blue variety called ‘Heavenly Blue.’ Given a sunny spot, this vine will provide dozens of new blooms every day, from mid-summer on. The perennial clematis vine is available in a number of blue-flowered cultivars, such as ‘Belle of Woking,’ with a double light-blue rosette-shaped blossom; and ‘Will Goodwin,’ ‘Blue Angel’ and ‘Mrs. Cholmondeley’, all with delicately blue-tinted pastel flowers.
Ipomoea tricolor 'Heavenly Blue' Clematis 'Belle of Woking'
Clematis 'Will Goodwin'Clematis 'Blue Angel'
Clematis 'Mrs. Cholmondeley'
Caryopteris and hydrangea are two well-known blue-flowering shrubs. Caryopteris (sometimes called bluebeard, blue mist or blue spirea) is a small shrub with woody stems which may die back in the winter in colder climates. Depending on the variety, this plant offers summer-to-fall flowers ranging from a soft powder blue to deep blue. Some mophead and lacecap varieties of the hydrangea shrub have the interesting ability to vary in flower color from pink to blue, depending on the chemistry of the soil, with those grown in more acidic soil tending to be blue. Certain varieties of evergreens such as spruce and juniper can be counted on to provide blue in the garden even during the winter.
Caryopteris x clandonensis 'Longwood Blue' Hydrangea macrophylla 'Endless Summer'
Juniperus chinensis 'Blue Point'
Blue flowers are brilliant but fleeting. You can keep that blue going all season long with the foliage of certain hostas and perennial grasses. The hostas ‘Halcyon,’ ‘Hadspen Blue,’ ‘Glacier Lake’ and ‘Blue Angel’ are just a few blue varieties which can be used to great effect when combined with bright golden-green hostas or the shade-tolerant gold and green-striped grass 'Hakonechloa macra 'Aureola.' Keep in mind that "blue" hostas take their color from a waxy sheen on the surface of the leaves which can be affected by the amount of sunlight and water the plant gets, so color can vary. Consider grasses such as the blue switch grass Panicum virgatum ‘Heavy Metal’ or blue oat grass, Helictotrichon sempervirens, to add season-long blue to a sunny spot.
Hosta 'Hadspen Blue'
Hosta 'Blue Angel'
Panicum virgatum 'Heavy Metal'
"Forget me not" photo courtesy of randihausken
Article photos thanks to the following DG members: ageratum, Evert; lobelia, jg48650; calibrachoa, ladyanne; myosotis, Dave; bachelor button, Joy; iris, Tntigger; veronica, htop; capanula, the1pony; delphinium, PotEmUp; aconitum, KevinMc79; chionodoxa, ladygardener1; muscari, Evert; hyacinth, chrisw99; scilla, pixie62560; allium, Terry; morning glory, Toxicodendron; clematis, Dea; clematis, DreamOfSpring; clematis, Galanthophile; clematis, Calif_Sue; caryopteris, daryl; hydrangea, tyke; hydrangea, tcfromky; picea, treelover3; juniper, Todd_Boland; hosta, Todd_Boland; hosta, Creeker; hosta, bentleygardens; panicum, plantdude; helictotrichon, poppysue