Overview and Description:
If your eye has been caught by a large swath of brilliant blue, in an early spring lawn, chances are excellent you're seeing naturalized Scilla sibirica. Siberian squill, grown from a small bulb, is probably the most familiar of the scillas. The plants themselves don't get much taller than about 6 inches, but they make up for their diminutive size by spreading out and blooming profusely.
The tiny bulbs grow and multiply easily and the plants will also self-seed, making scilla easy to grow and a perfect choice for naturalizing.
Scilla is a large genus with about 90 species, in the Hyacinthaceae family that includes cold hardy varieties as well as tropical plants. Scilla sibirica, or Siberian squill, is a native of Russia and Eurasia, not Siberica. It probably got that name because it is so cold hardy, it blooms down to USDA Zone 2!
- Leaves: Thin, sword-like leaves grow from the base of the plant and arch outward, allowing the flowers to be seen unobstructed.
- Flowers: The star or bell-shaped flowers nod and droop on short stems. There are 3-5 stems per plant, providing plenty of blooms.
Scilla need a period of cold and grow well in USDA Hardiness Zones 2 - 8
Although scilla grows best in full sun to partial shade, you can plant them just about anywhere, even under trees, since they bloom before the trees will have leafed-out.
These are small plants, reaching only 4-8 inches (10-20 cm) H x 4-6 inches (10-15 cm) W
Bloom time depends on the weather, but generally, it is early spring, March to April. Siberian squill is very cold hardy and can bloom through frost and even some snow.
- Scilla sibirica - When unspecified, they are usually the blue, star-shaped flowers.
- Scilla sibirica 'Spring Beauty - One of the larger scilla varieties with bell-shaped blue and up to 5 flower stalks per plant.
- Scilla sibirica alba - Rarer clear white flowers.
Plant scilla bulbs where they are free to roam. They can easily light up a lawn, but look much more natural under a tree, at the edge of a woodland or scattered throughout a rock garden.
Scilla bulbs can also be planted in containers and forced into bloom a few months early. They make great spring decorations on doorsteps or as centerpieces.
Mixing scilla with other early spring bulbs that spread, like Snowdrops and Glory-of-the-snow, which bloom a little earlier, will extend the show. Or try planting them under the Forsythia.
Soil: Scilla siberica is not very particular about soil, except that it be well-draining. They grow just about anywhere, however they do need regular water when first planted.
Planting Scilla Siberica: Scilla bulbs are planted in mid- to late fall, about a month before the first expected frost. The bulbs and plants aren't large, so you'll want to plant quite a few, to have any impact.
Scilla bulbs have a rounded bottom and the top comes to a point, so It's usually easy to see which end is up, although they'll find their own way if your bulbs are a bit ambiguous.
Plant the bulbs about 3-5 inches deep. You can space them close together, planting about 15 bulbs per square foot or 1 bulb every 3 inches. Scilla bulbs are often sold in bulk with packages of 100 or more not uncommon. It's generally easier to dig a wide hole and plant several bulbs at the same time, rather than poking that many individual holes.
Your scilla plants aren't going to be around past the cool, early months of spring, so little maintenance is required. Don't mow the foliage until about 6 weeks after the flowers bloom. The plants need time to create and store energy, before going dormant.
If you would like to transplant your scilla, you can either move a clump of bulbs or save the seed. Fall is ideal for transplanting bulbs, but it's easier to find them while they are still in bloom.
If you move them then, be sure to keep them well watered.
You can also plant any bulbs you forced in containers. Simply plant them 3-5 inches deep, after flowering, and keep them watered until the foliage disappears.
To save seeds, allow the pods to dry on the plants and then collect them and scatter. They will grow themselves.
Pests & Problems:
Pests don't seem to bother with Scilla siberica. If you are having trouble growing them or getting them to naturalize, it is probably a moisture problem. The prefer consistent moisture when first planted and while they are growing, but they don't really like sitting in the wet or damp soil, especially during the summer months, when they go dormant.
More on adding blue flowers to your garden.