Is there anyone who doesn’t love blue in the garden? Blue flowers, whenever they appear, contribute a cool, calming vibe to our garden beds, borders, and containers. And the spring blooming scilla (Scilla siberica) has some of the most vividly blue flowers imaginable.
While writing this article I looked online at color charts for help describing the shade. “Azure” fits, as does “deep sky blue,” “sapphire,” or “cerulean.” But these adjectives don’t do justice to the jolt of color that appears while much of the landscape is still brown and gray.
Nodding, bell-shaped flowers emerge in clusters accented by straplike emerald green leaves. Scilla’s flowers are some of the earliest to arrive, in late March and early April, usually right after the snowdrops. It’s categorized as a “minor” bulb along with snowdrops, grape hyacinth, and crocus, but there’s nothing minor about its impact in the garden.
Other common names for scilla are Siberian squill and wood squill. A member of the Asparagaceae family, its botanical Latin name comes from the Greek word skilla, for sea-squill. It is native to Southwest Russia, the Caucasus, and Turkey, but not Siberia.
Scilla is hardy in U.S.D.A. Plant Hardiness Zones 2 to 8.
Plant bulbs in fall, in full sun to part shade. Although scilla cannot tolerate deep shade (few flowering plants do), they will bloom in shadier conditions than most. They are low maintenance; pretty much plant and forget them. Deer, squirrels, and rabbits don’t eat the bulbs or flowers, and scilla tolerates black walnut. All parts of the plant are toxic to humans and animals if eaten, and the bulbs can cause skin irritation in some people.
The bulbs are not expensive, which is good, since for the best effect they should be planted in bunches of at least 25. Plant the bulbs 4-5” deep, spacing about 3” apart. Plants grow 6 to 12” tall.
As with all bulbs, scilla requires good drainage or they will rot. But they are not particular about soil type. They rarely need supplemental watering. Spring in many areas is often rainy anyway, so only water if it’s been unusually dry.
Because the color blue recedes in the garden, plant scilla where you can enjoy them up close rather than at a distance: along a walkway, at the front of a flower border, in rock gardens, and woodland gardens. Mine are planted under my native river birch. They look great with early daffodils or bloodroot. It’s said they make a good cut flower, but I enjoy mine where they are.
They are especially pretty planted in a lawn. The leaves have usually faded by the time the grass needs mowing.
There are a couple of varieties: S. siberica var. alba has white flowers, and S. siberica ‘Spring Beauty’ has flowers that are a deeper blue than the species. ‘Spring Beauty’ is the variety usually offered by bulb sellers.
While scilla is sold as bulbs, it also naturalizes from seed. Once the flower petals fade, the seed capsule turns deep purple and swells until it opens, sending seeds out to find new places to sprout. After it bursts, the leaves wither and the bulb goes dormant.
A downside of scilla is it’s such an enthusiastic self-seeder that in some areas of the U.S. it is classified as invasive. Check with your local native plant society before planting, and if it is, see what native flowers they recommend planting in its place.
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