Imagine springtime and you probably dream in yellow: daffodils, forsythia, sunshine. But the sun shines brightest in a blue sky. And the deep, rich tones of spring are blue, from palest pearl to deep marine: scilla, grape hyacinths, irises.
There are no blue daffodils and only a few almost-blue tulips. But among other spring-flowering bulbs, there’s a small orchestra of blue notes. Some blue bulbs descend from purple ancestors and may seem to have a tinge of violet or lavender. But others are true blue. And now is the time to plan for spring-blooming bulbs to be planted in October.
What goes with blue? Almost anything, although yellow is classic (think of Provencal pottery) and white is elegant. Blue can cool off hot pinks and oranges or go solo in a container.
Against the fresh greens of spring, you’ll need a mass of blue to make an impact. So plan to plant a bunch of bulbs in a group — no fewer than 25 crocus or scilla bulbs and five or more hyacinth or allium bulbs in any spot.
A few suggestions for spring blues:
Scilla siberica: In late March or early April, you’ll often see a banner-blue carpet beneath shrubs or in a laid-back lawn, with flowers nodding on 4- to 6-inch stems above lancelike leaves. Plant scilla (in ample quantity) among other bulbs, such as daffodils, and perennials, such as hostas. The most common cultivar is Scilla siberica “Spring Beauty.”
Hyacinths: Eight-inch-high towers of tiny flowers on short stems make a big statement in the garden, but they also are traditional for forcing indoors. Hyacinthus orientalis comes in a number of blue varieties including soft blue “Delft Blue” and navy “Blue Jacket.”
Grape hyacinths: Sturdy little pillars of tightly packed flowers look like tiny hyacinths when they bloom in May. There are species of muscari, from palest ice-blue to deep navy; Muscari azureum falls somewhere between. The most widely available is royal blue M. armeniacum. Its grassy foliage often returns in fall and persists through winter; be wary of planting them in a ground cover bed.
Alliums: Most alliums, with their globes of bloom atop tall stems in late spring, are purple or white. But Allium caeruleum (also known as A. azureum) has 1 1/2-inch-wide flower balls of true blue. Like other ornamental onions, it is distasteful to deer and squirrels (unless they’re really hungry).
Spanish bluebells: The English bluebell doesn’t grow well in Chicago, but Spanish bluebells (Hyacinthoides hispanica) with a tall stalk of powder-blue bells do just fine.
Rock garden iris: You’ll find a number of shades of blue among the dwarf irises that bloom in early March, including Iris reticulata “Harmony” — deep blue with a dash of yellow — and powder-blue I. reticulata “Cantab.” Because they bloom before almost anything else except snowdrops, it’s important to plant these irises in a generous mass so they stand out against brown leaves and mulch. And plant them by the sidewalk where you can enjoy them on a cold morning.
Camassia: While most of our spring bulbs are native to southwestern Europe and Central Asia, camassia comes from mountain meadows in the Pacific Northwest. It has 2-foot stalks with feathery spikes of flowers. Most species prefer moist sites; ice-blue Camassia leichtlinii tends to do best in Midwestern gardens.
Crocus: These starlets of early spring tend more toward purple, but some varieties can fairly be called blue. Crocus tommasinianus is a tiny, early species that needs to be planted closely in quantity for impact; the cultivar “Blue Pearl” is pale silvery blue. C. vernus is the familiar large-flowering species that blooms a little later. “Queen of the Blues” is a soft lilac-blue; “Twilight” is deep, truer blue.
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Planting spring-blooming bulbs
There’s nothing complicated about planting bulbs. And a little effort in autumn pays off with a glorious show in spring.
Most spring-blooming bulbs need pretty much the same conditions: full sun; soil that drains very well (amend it with plenty of compost if you have clay); and a cold winter.
Plant bulbs beginning in early October, when nights are cold enough so they will stay dormant and won’t sprout. You can plant bulbs any time until the ground freezes, but it’s safest to get them in the ground before Thanksgiving.
Dig a hole two to three times as deep as the bulb is wide (deeper is better). It isn’t necessary to fertilize bulbs when planting them, but if you like, you can add slow-release bulb fertilizer in the bottom of the hole according to the package directions.
Set the bulb in the hole pointy end up. If you can’t see a pointy end, guess; it’s not critical. Even if the bulb ends up sideways, the new shoot will find its way to the surface.
To plant a bunch of bulbs in the same spot, use a shovel to dig a wide hole. Arrange the bulbs on the bottom before refilling it. For a single bulb, a slender trowel works well.
Fill the hole and water well. Cover the planting zone with 1 to 2 inches of mulch, such as shredded leaves. The mulch keeps the soil cold so brief late-winter thaws don’t make the bulbs sprout early and get frost-bitten.
Spring bulbs need to stay thoroughly cold for at least 3 1/2 months before they will bloom. They can be forced into flower indoors early in spring, but only if they have spent the necessary time at temperatures between 32 and 40 degrees. Pot them up in fall in good potting mix and place the container in an unheated garage or crawl space. Bring it indoors to a sunny window and begin watering it in late February or early March.
Choose a range of early, mid- and late-blooming species and varieties to extend the spring bloom in your garden.
Buying bulbs
Garden centers sell a variety of bulbs. Online sources include White Flower Farm (whiteflowerfarm.com), John Scheepers (johnscheepers.com) and McClure & Zimmerman (mzbulb.com).
— B.B.
