Star of Bethlehem (Ornithogalum umbellatum) is a flowering perennial bulb that grows in clumps with narrow, grass-like leaves about 1 foot long. In the late spring, flower stems rise up from the foliage, each bearing around 10 to 20 star-shaped blooms that are less than an inch across. The flowers open in the late morning and close once the sun goes down or during cloudy weather. Star of Bethlehem has a fast growth rate and will quickly spread. The bulbs should be planted in the fall for spring flowers. Note that is considered invasive in some regions.
This plant is toxic to both humans and animals.
|Common Name||Star of Bethlehem, eleven-o'clock lady, nap-at-noon, grass lily, summer snowflake, sleepy dick|
|Botanical Name||Ornithogalum umbellatum|
|Plant Type||Perennial, bulb|
|Mature Size||6–12 in. tall, 12–24 in. wide|
|Sun Exposure||Full, partial|
|Soil Type||Loamy, moist, well-drained|
|Soil pH||Acidic, neutral, alkaline|
|Flower Color||White with green stripe|
|Hardiness Zones||4–9 (USDA)|
|Toxicity||Toxic to people and pets|
Star of Bethlehem Care
Star of Bethlehem bulbs should be planted in holes 3-6 inches deep in loamy, moist but well-draining soil with the pointed end facing up; space the bulbs at least 4 inches apart. A sunny location will provide the best flower show, but partial shade is acceptable. If you live in a colder part of the plant’s growing zones, add a 3-inch layer of mulch over your bulbs for winter protection. Remove the mulch once the ground thaws in the spring and the plants start to emerge.
Star of Bethlehem readily escapes gardens and has naturalized in many regions of North America. Its bulbs multiply rapidly, and the flowers also readily self-seed. In many states, this foreign plant earns a severe "Do Not Plant" warning against invasiveness. Check with local experts before inviting this plant into your garden.
Although it can grow in partial shade, Star of Bethlehem prefers a spot with full sun, meaning at least six hours of direct sunlight on most days. Its flowering will be better in full sun.
Star of Bethlehem likes loamy soil. Sharp soil drainage is key for healthy growth. In waterlogged soil, the bulbs can rot.
Young Star of Bethlehem plants need regular watering to keep the soil evenly moist but not soggy. Mature plants have some tolerance for dry soil, but they still prefer a moderate amount of moisture. While the plant is actively growing in the spring and summer, water when the soil feels dry a couple inches down. When the plant is dormant, its moisture needs are diminished, and it typically doesn't need any supplemental watering. Stop watering when the foliage begins to turn yellow after the flowers are spent.
Temperature and Humidity
Star of Bethlehem is quite hardy to the temperature extremes of its growing zones (4 to 9). Humidity also typically isn't an issue, as long as its soil moisture needs are met.
Star of Bethlehem flowers best when grown in rich soil. Mix some compost into the soil each spring to promote healthy growth. Additional fertilizing is not necessary, and may even hinder flowering.
Types of Ornithogalum
Star of Bethlehem does not have any named cultivars, but the Ornithogalum genus contains 200 other species similar to Star of Bethlehem flower. They include:
- Ornithogalum arabicum: This plant bears white flowers and grows to around 19 inches tall. It's hardy in zones 9 to 10.
- Ornithogalum dubium: This species features orange flowers and reaches only around 10 inches tall. It grows in zones 7 to 10.
- Ornithogalum nutans: This species grows to around 16 inches high and has white flowers with a lot of green in them. It grows in zones 6 to 10.
- Ornithogalum thyrsoides: This species also has white flowers and grows to around 16 inches tall. It's hardy in zones 7 to 10.
After Star of Bethlehem flowers finish blooming, you will be left with a mass of tangled foliage that isn't particularly attractive. However, resist the urge to remove that foliage. As long as it stays green, it will be feeding the bulbs through photosynthesis. Ultimately the leaves will turn brown and the plants will go dormant in the summertime, leaving gaps in your garden bed, at which time the foliage can be removed. Many gardeners opt to plug those gaps with annual plants, while others grow perennials next to their Star of Bethlehem plants that will fill in the space as summer progresses.
While deadheading the spent flowers does not prompt additional blooming, it does limit the spread of the plant by eliminating the seeds that readily volunteer wherever they fall in the garden.
Propagating Star of Bethlehem
The bulbs will multiply prolifically over time, producing what are referred to as offsets or bulbils. Here's how to propagate the plant:
- In late summer as the foliage is dying back, use a shovel or trowel to dig up the bulbs.
- Carefully separate the offset bulbils clinging to the parent bulb.
- Immediately replant the bulbils and parent bulbs about 3-6 inches deep and 4 inches apart in moist, loamy soil. The smallest bulbils may require a full two years before they are mature enough to bloom.
How to Grow Star of Bethlehem From Seed
Star of Bethlehem flower seeds are very tiny and hard to handle, but the plants spread readily via self-seeding. These volunteers sprouting up around the parent plant can be easily dug up and transplanted to a new location, but it may take a few years for them to develop mature bulbs that produce flowers.
If you want to curb the spread of this plant, deadhead the flowers (remove the spent blooms) before they drop their seeds.
Potting and Repotting Star of Bethlehem
Because the bloom season is short and the foliage then dies back, Star of Bethlehem is rarely grown in containers. That said, there's no reason you can't grow it in a well-draining pot of any material, filled with standard commercial potting mix. After the pots bloom and the foliage fades, move them to a protected, out-of-sight location to overwinter before bringing them back into the open the following spring.
Within its hardiness range (zones 4 to 9), star of Bethlehem is a sturdy plant that rarely succumbs to winter cold. However, gardeners in the northern part of zone 4 may want to protect plants in exposed locations with a layer of dry mulch over the winter. Avoid letting the bulbs soak in cold wet ground, as this can encourage bulb rot. The bulbs can also be dug up and stored in a protected space, such as a basement, in extremely cold areas.
Common Pests & Plant Diseases
Star of Bethlehem has no serious pest enemies of note. The only disease that affects it is bulb rot where soils are barren and poorly draining.
How to Get Star of Bethlehem to Bloom
Star of Bethlehem normally produces an impressive flush of white flowers for several weeks in May and June, with 10 to 20 starry white flowers on each stem. The flowers generally open about noon, then close at sunset or when the skies are cloudy.
Poor flowering can result if the plant is not getting enough sunlight, if it is overfed with nitrogen-rich fertilizer, or if the bulbs are not yet mature enough. Propagating offsets may require two years before they flower, and plants started from seeds can take even longer.
Common Problems With Star of Bethlehem
The only significant problem with this plant is its eagerness to spread aggressively. Take care when planting it in a mixed garden bed, as it can take over the space and displace other garden plants. This plant is best used as an underplanting around rose bushes or sturdy shrubs, or in confined meadowy areas where there is no chance of its spread elsewhere.
Eliminating a colony takes some diligence, requiring that you carefully dig up the bulbs as you notice plants emerging in the spring. Because Star of Bethlehem also self-seeds so easily, you'll also need to keep an eye out for tiny volunteers that can fuel a resurgence of a troublesome colony.
How did this plant get its common name?
A folktale talks of fragments of the biblical Star of Bethlehem falling from the sky and taking root as Ornithogalum plants. Several other common names derive from the plant's habit of opening at midday and closing in cloudy or dark conditions.
How should I use this plant in the landscape?
Do so carefully. Star of Bethlehem is a vigorous plant that is eager to spread and naturalize outside the confines of the garden. In meadows and woodlands, it will quickly establish colonies. In the confines of the garden, it is best used for underplanting beneath roses and shrubs, where its spread can be supervised.
Is there a similar plant that is not so invasive?
Try Allium neapolitanum (daffodil garlic), a form of false onion with similar flowers. It is hardy in zones 7 to 9. Other species in the Allium genus are also available for colder regions. Alliums are much easier to control than Star of Bethlehem.
Star of Bethlehem. Missouri Department of Conservation.
Star of Bethlehem. Missouri Department of Conservation.
Star of Bethlehem. Invasive Plant Atlas.
Ornithogalum umbellatum. Gardenia.