Scilla

scilla

( SILL - uh )

At-A-Glance Information

Commonly called Squill or Bluebell, this genus of flowering perennials grow from bulb and need full sun to partial shade and regular water during growth and blooming periods. They have many applications in the garden, depending on the species grown and are wonderful in mixed borders, in clumps along pathways or when grown in containers. Take care when planting these blooms in the garden, as all plant parts are highly toxic if ingested by humans or pets.

Scilla Species and Varietals

The genus Scilla is a member of the plant family Asparagaceae and includes between 30 and 80 species. The plants in this genus are closely related to Puschkinia (Striped Squill), and Hyacinthoides (Bluebell). Scilla growing zones vary depending on the species cultivated. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Scilla amoena (Star Hyacinth, Squill, Pretty Squill)
These plants are perennial bulbs which reach between 6 and 10 inches tall when in flower. Each plant produces between four and five strappy, green leaves with reddish undersides. They are typically longer than scapes. Individual plants produce one to three flower stems that are angular and somewhat compressed. Flowers are light blue with dark central veins. This species grows well in USDA hardiness zones 3-9.

Scilla bifolia (Alpine Squill, Two-Leaf Squill)
This species grows well in USDA hardiness zones 4-8 or Sunset growing zones 2-11 and 14-21. Each flowering stem holds three turquoise-blue flowers. Varieties with white, violet blue, and pale purple-pink blooms are available as well. Each bulb in this species produces only two leaves. Cultivar 'Rosea' has pale pink to white flowers.

Scilla forbesii (Scilla siehei, Chionodoxa forbesii) (Forbe's Glory-of-the-Snow, Siehe's Glory-of-the-Snow, Snow Lily, Kar-Zambak, Karın İhtişamı, Kar Görkemi, Fethiye Purple-Star, Fethiye Moryıldızı)
These plants are native to western Turkey and seed readily, forming colonies. Each bulb produces two leaves and short flowering stems that hold multiple blue-violet blooms with whitish centers. This species is suited for USDA hardiness growing zones 3-9.

Scilla litardierei (Amethyst Meadow Squill, Dalmatian Scilla)
These plants produce blue Grape Hyacinth type flowers that bloom in late springtime. Plants are bulbous perennials, and produce three to six grass-like leaves that taper to a point. Each flower spike containers up to 70 star-shaped flowers and reach between 6 and 8. This species is best in USDA hardiness zones 4-8.

Scilla lucilia (Bossier's Glory-of-the-Snow, Lucile's Glory-of-the-Snow, Glory-of-the-Snow, Kar Görkemi or Karların İhtişamı, Bozdağ Sümbülü)
This species of Squill is native to western Turkey, and produces flowers in early springtime. After flowering, plants go dormant until the next spring. The specific epithet honors the wife of Swiss botanist Pierre Edmond Bossier. Flowers are lilac blue to violet and have white centers. Stems reach up to 8 inches tall. This species does well in USDA hardiness zones 3-8.

Scilla mischtschenkoana (Mishchenko, Misczenko Squill, Early Squill, Early Squill)
This species grows well in USDA hardiness zones 4-8 or Sunset Growing zones 1-11 and 14-21 and has pale blue flowers with darker blue stripes. Blooms appear in late wintertime or early springtime. The main cultivar of this species is 'Tubergeniana', or the Tubergen Milk Squill or White Squill, which has ice blue to milky white blooms with a cyan midrib on each petal and grows to 3 to 6 inches tall.

Scilla peruviana (Peruvian Scilla, Portuguese Squill, Hyacinth of Peru, Peruvian Hyacinth, Cuban Lily)
This species grows best in USDA hardiness zones 8-10 or Sunset growing zones 14-17 and 19-24 and grows from a large bulb. Flowers are bluish purple and bloom in clusters of up to 50 in late spring. A white-blooming variety is also available. Individual plants reach up to 6-18 inches tall and 6-12 inches wide at maturity and spread over time to form clumps.

Scilla siberica (Siberian Squill, Wood Squill, Blue Squill)
This species grows in USDA hardiness zones 3-8 or Sunset growing zones A2, A3, 1-7 and 10 and has blue bell-shaped flowers. Cultivars of this species include 'Alba' (with white flowers) and 'Spring Beauty' (with dark blue flowers that are larger than the species'). This species is considered invasive in northeastern North America, the Great Lakes region, the Midwest, and parts of eastern Canada.

Caring for Scilla

Plant in fall, spacing bulbs 2-3 inches deep and 4 inches apart for cold-hardy species and 3-4 inches deep and 6 inches apart for species like Scilla peruviana. They appreciate a space in the garden that has space for them to spread; they typically naturalize over a wide area, especially when grown in a protected area like under a deciduous tree. Pick a spot that gets partial shade to full sun. They appreciate around 6 hours of sun each day to bloom and grow well. They do not flower or naturalize well when planted in full shade, and do not do so well under evergreen trees. Ensure that soil is well-draining, rich with plenty of organic matter added, and has a pH of between 6.0 and 7.0 (slightly acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. This layer of mulch will also help to insulate bulbs over the cool months of the year. Water new plantings regularly as they establish a strong root system in their new home. At maturity, these flowers like regular waterings during their active blooming and growth seasons in spring and early summertime.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These plants are not heavy feeders, and this should be sufficient to provide the necessary nutrients for the active growing and flowering seasons. Prune to remove spent flowering stems (unless you will be harvesting seeds for propagation). When foliage yellows after blooms fade, withhold water but do not let the soil dry out completely. Do not remove foliage until it fully yellows, as when it is green it is still photosynthesizing, gathering and sending energy to the underground storage bulb. Divide clumps only when vigor and flowering decline; otherwise leave them be. For instructions on how to successfully.

Growing Scilla in Containers
Squill do well in clay pots with large drainage holes in the bottom, which allow water to escape quickly so that the bulbs will not rot out. Use well-draining somewhat sandy potting mix, and ensure that good drainage is occurring before installing bulbs. Place bulbs 3 inches deep under the substrate surface with their pointed ends up. Place them close to each other but not touching. Water regularly during the active growth and blooming periods in springtime, and lessen waterings after flowers fade and again after foliage fades in summer. Plants may outgrow their containers during the growing season. If this happens, they tend to not grow well because their root space is constricted, and plants will need to be divided. For instructions on how to successfully divide Squill flowers, see the Propagation section below.

Propagation

Scilla, or Squill, can be propagated either by division or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the division method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. Note that seed-grown Scilla can take between 3 and 5 years to reach maturity (flowering). To propagate your Squill, follow the instructions below:

Propagating Scilla by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds. In the springtime after flowers have finished blooming, locate the seed pods which develop in their place. Seeds are mature when the pods are dry, brittle and brown. Remove these pods from the plant and open them to access the seeds. Place them on a paper towel and leave them to dry out a bit in a cool, dark area. They can then be cold-stratified to prepare for planting, or stored in an airtight container in a cool, dark place.
For Squill seeds to germinate, they will need to undergo cold-stratification, which mimics the conditions in their native environments. To complete this treatment, place seeds in a sealable bag or other container filled with moistened sand or peat moss, and then place that container in the refrigerator or a similarly cool environment. Leave the container there for up to three months' time, and then remove seeds and get ready to sow them. They may have sprouts beginning to form.
In either late winter or early springtime, get your container prepared. Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray on the surface of the soil. Cover them with a light layer of soil and water with your spray bottle to avoid dislodging the seeds. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 6-8 weeks from sowing.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 65 and 72 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home.

Propagating Scilla by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil, compost and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in very early spring (after the plant has entered dormancy, but before it has begun its new spring growth), and needs to be done every few years regardless of whether you have the goal of propagating the plants for best performance. To propagate by division, follow these steps:

Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the bulb(s). Once you have worked it up out of the ground, lay it out. Tap or brush off any dirt that comes up with the bulbs.
Start to investigate the bulbs with your fingers. Larger bulbs are best for division. Smaller bulbs can simply be replanted on their own. Gently pull the larger bulbs and their bulblets apart to separate them.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your bulbs 3 inches deep spaced 3 inches apart with their pointed ends up and water thoroughly.

Scilla flowers fade to reveal seed pods that will open to reveal black seeds.

Scilla seeds are round and black and have rough exteriors.

Problems and Pests

Certain Scilla species are considered invasive in some regions; see the species descriptions above for more information. Check with local authorities before planting. Scilla plants, although typically quite resilient, can be susceptible to developing issues with the following pests and diseases in the landscape: