Can Star of Bethlehem Be Planted Outside? - Plant Care Guide

Yes, Star of Bethlehem (Ornithogalum umbellatum) can certainly be planted outside, and in many regions, it thrives so well that it is considered an invasive species. This charming spring-flowering bulb is hardy and spreads vigorously, creating beautiful drifts of white, star-shaped flowers, but its invasive nature requires careful consideration before planting in a garden setting.

What is the Star of Bethlehem Plant?

The Star of Bethlehem plant (Ornithogalum umbellatum) is a small, spring-flowering bulbous perennial belonging to the Asparagaceae family (though sometimes classified in the Liliaceae family). It's named for its distinctive, star-shaped white flowers, which bloom in clusters in late spring. Despite its delicate appearance, it is remarkably resilient and often considered a tenacious garden plant.

Here are the main features of the Star of Bethlehem plant:

• Foliage:
  • Produces narrow, grass-like leaves, typically about 6-12 inches (15-30 cm) long.
  • The leaves often have a distinctive silvery-white stripe down the middle.
  • Foliage emerges in early spring, often before other plants, and usually dies back (senesces) by early summer after the plant has flowered and stored energy in its bulbs.
• Flowers:
  • The star attraction: clusters of six-petaled, star-shaped white flowers that appear on a leafless stem (scape) about 6-12 inches (15-30 cm) tall.
  • Each flower typically has a prominent green stripe on the underside of its petals, visible when the flower is closed.
  • Flowers usually open on sunny days and close at night or on cloudy days.
  • Blooms in late spring (April-May), bringing a burst of white to the garden.
• Bulbs:
  • Grows from small, white, onion-like bulbs.
  • A key characteristic is its prolific production of offsets or "bulbils" (tiny bulblets) around the main bulb. This is its primary method of rapid spread.
• Hardiness:
  • Very hardy, typically growing in USDA Hardiness Zones 3-8, making it adaptable to a wide range of climates.
• Native Range:
  • Native to parts of Europe, Asia, and northern Africa.
• Common Names:
  • Also known by other names such as nap-at-noon (due to flowers closing in the afternoon), sleepy dick, and dove's dung.

While visually appealing, its aggressive spreading nature is a significant characteristic that gardeners must consider.

What Are the Ideal Growing Conditions for Star of Bethlehem Outdoors?

The Star of Bethlehem (Ornithogalum umbellatum) is not particularly fussy, but providing ideal growing conditions outdoors will ensure it thrives – perhaps too well, given its invasive tendencies. Its resilience is part of its charm and challenge.

Here are its ideal outdoor growing conditions:

• Sunlight:
  • Full Sun to Partial Shade: It performs best in full sun (at least 6 hours of direct sunlight) but tolerates partial shade (4-6 hours of direct sun or dappled light). In shadier spots, it might produce fewer flowers or grow less vigorously.
• Soil:
  • Well-Drained Soil: This is crucial. Like most bulbs, Star of Bethlehem needs well-drained soil to prevent its bulbs from rotting. It's quite adaptable and will grow in sandy, loamy, or even clay soils as long as drainage is adequate.
  • pH: It's tolerant of a wide range of soil pH, from slightly acidic to slightly alkaline (6.0-8.0).
  • Fertility: It's not a heavy feeder. While it tolerates poor soil, adding some compost or a balanced granular fertilizer in the fall can improve vigor and flowering.
• Watering:
  • Moderate Moisture During Growth: It prefers moderately moist soil during its active growth period in spring when leaves and flowers are present.
  • Dry During Dormancy: Once the foliage dies back in early summer, the bulbs prefer a relatively dry period during dormancy. This is a natural fit for many temperate climates with drier summers.
• Hardiness:
  • Cold Hardy: It is extremely cold hardy, typically thriving in USDA Zones 3-8. It requires a cold winter dormancy to flower.
• Space:
  • Given its spreading nature, it prefers areas where it has room to naturalize or where its spread can be managed (e.g., in contained beds, under deciduous trees, or naturalized areas where you don't mind a groundcover).

These conditions, coupled with its vigorous reproductive methods, explain why it can be such a persistent and widespread plant in suitable climates.

Is Star of Bethlehem Considered an Invasive Plant?

Yes, the Star of Bethlehem (Ornithogalum umbellatum) is indeed considered an invasive plant in many parts of North America and other regions outside its native range. Its aggressive spreading habit can quickly outcompete native plants and become a significant nuisance in gardens and natural areas.

Here's why it's deemed invasive:

• Rapid Reproduction by Offsets (Bulbils): This is its primary and most effective method of spread. Each main bulb produces numerous tiny offsets or "bulbils" annually. These new bulblets grow around the parent bulb, quickly forming dense clumps and expanding the plant's footprint.
• Seed Production: While its seeds can also contribute to its spread, the rapid propagation via bulbils is the more dominant force behind its invasiveness.
• Persistence: The bulbs are very resilient. Even small fragments left behind after digging can re-sprout into new plants, making eradication extremely challenging.
• Early Emergence and Dormancy: Its foliage emerges very early in spring, giving it a head start over many native plants. It then dies back by early summer, going dormant and disappearing from view, which makes it harder to manage or apply herbicides during the active growth period of other plants.
• Ecological Impact: In natural settings, it can form dense monocultures, displacing native wildflowers and grasses, reducing biodiversity, and altering ecosystem dynamics.
• Garden Nuisance: In gardens, it can quickly colonize flowerbeds, lawns, and even vegetable patches, becoming very difficult to eradicate and interfering with the growth of desired plants. It can be a very frustrating weed for gardeners.

Due to its invasive nature, planting Star of Bethlehem is often discouraged or even prohibited in some areas. If you choose to plant it, it's essential to do so with extreme caution and containment in mind.

How Does Star of Bethlehem Spread So Rapidly?

The Star of Bethlehem (Ornithogalum umbellatum) spreads so rapidly due to a highly effective combination of vegetative propagation via abundant offsets (bulbils) and, to a lesser extent, seed dispersal. Its life cycle is perfectly adapted for aggressive colonization.

Here's a breakdown of its rapid spread:

1. Prolific Production of Offsets (Bulbils): This is the primary mechanism.
   • Each mature main bulb of Star of Bethlehem can produce numerous tiny bulblets or "bulbils" around its base every year.
   • These offsets develop rapidly and, once separated from the parent bulb (either naturally or through soil disturbance), they grow into new, independent plants.
   • This continuous production quickly leads to the formation of dense, ever-expanding clumps and mats of plants.
2. Bulbil Persistence and Fragmentation:
   • The bulbils are small, hardy, and resilient. If you try to dig up a clump, it's virtually impossible to remove every single bulbil. Any tiny piece left behind in the soil can readily re-sprout into a new plant.
   • Tilling or digging can inadvertently chop up the main bulbs and spread the bulbils even further, essentially propagating the plant throughout the disturbed area.
3. Seed Production and Dispersal:
   • After flowering, the plants produce seed capsules containing small seeds.
   • These seeds can be dispersed by wind, water, or even by ants, further contributing to the spread, particularly to new, distant areas. While seed production is secondary to bulbil spread, it helps the plant colonize new sites.
4. Ephemeral Foliage and Dormancy:
   • The plant's foliage emerges early in spring, allowing it to capture sunlight before deciduous trees leaf out.
   • By early summer, the foliage dies back and the plant goes dormant. This makes it difficult to detect and treat during much of the growing season when other plants are active. The bulbs simply sit underground, accumulating energy and producing more bulbils, unseen.

This combination of efficient vegetative propagation, hardy and persistent bulbils, and an advantageous growth cycle allows Star of Bethlehem to rapidly colonize and dominate garden beds, lawns, and natural areas.

What Are the Risks of Planting Star of Bethlehem in Your Garden?

Planting Star of Bethlehem (Ornithogalum umbellatum) in your garden carries several significant risks, primarily due to its aggressive, invasive nature and mild toxicity. Understanding these risks is crucial before introducing it to your landscape.

Here are the main risks:

• Aggressive Spread and Invasion:
  • Difficult to Eradicate: This is the biggest risk. It spreads relentlessly through prolific bulbils and can quickly form dense mats, taking over flowerbeds, lawns, and even encroaching into paved areas. Once established, it is extremely difficult to remove entirely. Even tiny bulbils left behind will resprout.
  • Outcompetes Desired Plants: It will compete with your cultivated flowers, shrubs, and vegetables for water, nutrients, and sunlight, often smothering smaller or less vigorous plants.
  • Problem in Lawns: It can become a persistent weed in lawns, its foliage emerging early and then dying back, creating bare patches.
• Toxicity:
  • Poisonous to Humans and Pets: All parts of the Star of Bethlehem plant, especially the bulbs, are considered toxic if ingested. They contain cardiac glycosides similar to those found in foxglove, though generally in lower concentrations.
  • Symptoms: Ingestion can cause gastrointestinal upset (nausea, vomiting, diarrhea). In larger quantities, or for sensitive individuals or small pets, it could potentially cause more serious cardiac symptoms, though this is rare with accidental garden exposure.
  • Risk to Grazing Animals: It can be a particular risk in pastures where grazing animals might consume it.
• Ecological Damage (for natural areas):
  • If it escapes cultivation into nearby natural areas, it can outcompete native wildflowers and grasses, leading to a reduction in local biodiversity and altering natural ecosystems.
• Messy Dormancy: Its foliage dies back in early summer, leaving unsightly yellowing leaves and bare patches in the garden until other plants fill in, or until it re-emerges the following spring.

Given these substantial risks, many gardeners, especially those in regions where it's considered invasive, choose to avoid planting Star of Bethlehem altogether. If it's already present, focus on diligent management.

Is Star of Bethlehem Poisonous to Pets or Livestock?

Yes, Star of Bethlehem (Ornithogalum umbellatum) is poisonous to pets and livestock if ingested. All parts of the plant, but especially the bulbs, contain toxic compounds called cardiac glycosides.

Here's a breakdown of the risks:

• Toxicity Level: It is considered moderately toxic. While a small nibble might cause only mild irritation, ingestion of larger quantities, particularly the bulbs, can lead to more serious symptoms.
• Toxic Compounds: The active toxins are cardiac glycosides, which can affect the heart.
• Symptoms in Pets (Dogs, Cats):
  • Gastrointestinal Distress: Most common symptoms include nausea, vomiting, diarrhea, and abdominal pain.
  • Lethargy: A general lack of energy or sluggishness.
  • More Severe Symptoms (rare but possible with large ingestion): If a significant amount is consumed, especially the bulbs, it could potentially affect the heart, leading to changes in heart rate, weakness, or collapse.
• Symptoms in Livestock (Horses, Cattle, Sheep):
  • Grazing animals are at higher risk if the plant is present in pastures.
  • Symptoms can include severe gastrointestinal upset (colic, diarrhea), weakness, irregular heartbeat, and, in severe cases, cardiac failure.
• Prevention:
  • If you have pets that graze or chew on plants, avoid planting Star of Bethlehem.
  • If it's already in your yard, consider removing it completely (being diligent about getting all the bulbs) or fencing off affected areas.
  • Educate children and family members about its toxicity.

If you suspect your pet or livestock has ingested Star of Bethlehem, contact your veterinarian or a pet poison control center immediately. Provide as much information as possible about the amount consumed and any symptoms observed.

How Do You Control an Existing Star of Bethlehem Infestation?

Controlling an existing Star of Bethlehem infestation can be very challenging due to its prolific bulbil production and persistence. It requires a combination of diligent manual removal and sometimes chemical treatment over an extended period. Patience and consistency are key.

Here's a multi-pronged approach to control:

1. Manual Removal (Digging):
   • Best Time: The most effective time to dig is in early spring when the leaves have emerged but before flowering, and the soil is soft and moist. This is when the bulbs are actively growing and storing energy.
   • Method: Carefully dig out the entire clump, aiming to remove all the bulbs and bulbils. You'll need to go deep and wide, as bulbs can be several inches underground.
   • Extreme Thoroughness: This is where most people fail. Even a tiny bulbil left behind will re-sprout. Sift through the soil, if possible, to catch all fragments.
   • Disposal: Do not compost the removed bulbs and soil. Bag them and dispose of them in the trash to prevent further spread.
   • Repeat: Expect to repeat this process for several years, as dormant bulbils will inevitably emerge.
2. Solarization (for larger areas):
   • Method: Cover the infested area with clear plastic sheeting (4-6 mil thick) during the hottest months of summer. Secure the edges to trap heat.
   • Benefit: The sun's heat can kill bulbs and dormant seeds by "cooking" them.
   • Duration: Leave the plastic in place for at least 6-8 weeks, or longer.
3. Smothering/Deprivation:
   • Method: Cover the area with a thick layer of cardboard or black plastic, topped with several inches of mulch. This deprives the bulbs of light and eventually starves them.
   • Duration: This needs to remain in place for at least one full growing season, preferably two, to be effective.
4. Herbicide Application (Use with Caution):
   • Timing is Critical: Herbicides are most effective when the plant is actively growing and photosynthesizing, usually in early spring when foliage is lush (but before it dies back in early summer).
   • Type of Herbicide: Use a broad-leaf herbicide containing glyphosate (non-selective, will kill everything) or triclopyr. For use in lawns, look for selective broadleaf weed killers that won't harm turfgrass (ensure it's safe for your lawn type).
   • Application: Follow product instructions precisely. Apply on a calm, non-windy day. Spot treat to avoid harming desirable plants.
   • Repeat: Multiple applications over several seasons will likely be necessary, as herbicides may not kill all the underground bulbils in one go.
5. Prevent Flowering and Seeding:
   • If you can't remove them, at least cut off flower stalks before they go to seed. This prevents new seeds from spreading, though it won't stop bulbil production.
6. Maintain Vigilance:
   • Regularly monitor the area for any new shoots. The fight against Star of Bethlehem is a marathon, not a sprint.

Always start with manual methods and consider herbicides only if necessary, ensuring careful and targeted application to minimize environmental impact.

What Are Non-Invasive Alternatives to Star of Bethlehem?

If you appreciate the delicate white, star-shaped flowers that bloom in spring but want to avoid the invasive nature of Star of Bethlehem, there are several beautiful and non-invasive alternatives that can provide similar aesthetic appeal without the garden takeover.

Here are some excellent non-invasive alternatives:

• Snowdrops (Galanthus nivalis):
  • Why it's a good alternative: One of the earliest spring bulbs, producing elegant, nodding white flowers that emerge even through snow. They naturalize gracefully without becoming aggressive.
  • Bloom Time: Very early spring, earlier than Star of Bethlehem.
  • Toxicity: Mildly toxic, but less persistent than Star of Bethlehem.
• Glory-of-the-Snow (Chionodoxa forbesii or luciliae):
  • Why it's a good alternative: Features bright blue, pink, or white star-shaped flowers that form carpets in early spring. They naturalize well but are not considered invasive.
  • Bloom Time: Early to mid-spring.
  • Toxicity: Generally considered non-toxic.
• Siberian Squill (Scilla siberica):
  • Why it's a good alternative: Produces vibrant blue, bell-shaped flowers (sometimes white or pink) in early spring. It naturalizes readily but is generally not as aggressive as Star of Bethlehem and provides a stunning blue contrast.
  • Bloom Time: Early spring.
  • Toxicity: Mildly toxic.
• Dutch Crocus (Crocus vernus and other species):
  • Why it's a good alternative: Classic spring bulbs with cup-shaped flowers in a wide range of colors, including white. They naturalize easily and come back year after year.
  • Bloom Time: Early to mid-spring.
  • Toxicity: Mildly toxic.
• Grape Hyacinth (Muscari armeniacum):
  • Why it's a good alternative: Known for its clusters of bell-shaped, usually blue flowers that resemble miniature grapes. It's a charming spring bulb that naturalizes and is generally well-behaved.
  • Bloom Time: Mid-spring.
  • Toxicity: Mildly toxic.
• White Hyacinth (Hyacinthus orientalis 'Carnegie' or 'White Pearl'):
  • Why it's a good alternative: For a more substantial white flower with a powerful fragrance. These are larger bulbs that provide a strong vertical element.
  • Bloom Time: Mid-spring.
  • Toxicity: Mildly toxic.

These alternatives offer the beauty of spring bulbs, including various white, star-shaped, or bell-shaped flowers, without the long-term struggle of managing an invasive plant like Star of Bethlehem. Always check local guidelines for plant recommendations in your specific region.