Sea Onion Plant: Identification and Safety Guide

The sea onion plant (Drimia maritima), also known as sea squill, is a highly toxic bulbous plant commonly mistaken for edible onions. All parts contain cardiac glycosides that can cause severe poisoning or death if consumed.

Imagine hiking along a coastal trail and spotting what appears to be wild onions. Before you consider adding them to your foraged meal, you need critical information that could save your life. This guide provides essential identification techniques, safety protocols, and scientific facts about the dangerous sea onion plant.

What Exactly Is the Sea Onion Plant?

The sea onion plant (Drimia maritima), formerly classified as Urginea maritima, belongs to the Asparagaceae family. Despite its common name and onion-like appearance, this plant contains no relation to edible Allium species. Native to Mediterranean coastal regions, it thrives in sandy soils along shorelines and has spread to similar habitats worldwide.

Naturalists and foragers frequently confuse sea onion with edible varieties due to superficial similarities in bulb structure. However, understanding the critical differences is essential for safety. This plant produces a single flower stalk up to 6 feet tall with white or pink flowers, while its leaves emerge separately after flowering—a key identification feature distinguishing it from true onions.

Where Does Sea Onion Grow and When to Be Cautious

Sea onion primarily grows in coastal regions with Mediterranean climates, including:

• Shorelines of the Mediterranean Sea
• Coastal California
• Australia's southern coastlines
• South Africa's western regions

The plant's seasonal growth pattern creates specific danger periods. Its large bulbs (up to 4 pounds) remain dormant during summer, then produce leaves in fall while the distinctive flower stalk emerges in spring. This separation of leaf and flower growth differs from edible onions, which produce both simultaneously.

Critical Identification Guide: Spotting the Dangerous Differences

Accurate identification prevents potentially fatal mistakes. Consider these distinguishing characteristics when evaluating any "onion" you encounter:

Feature	Sea Onion (Drimia maritima)	Edible Wild Onion (Allium spp.)
Smell	No onion/garlic odor	Distinctive onion/garlic scent
Leaves	Flat, broad, emerge after flowering	Cylindrical, hollow, grow with flowers
Bulb Skin	Dark brown, paper-like, layered	Papery but thinner, often white/purple
Flower Timing	Flowers before leaves appear	Flowers and leaves present together

Why Sea Onion Poses Serious Health Risks

The sea onion plant contains cardiac glycosides, particularly scillaren A and B, which affect heart function. According to the American Association of Poison Control Centers, ingestion of even small amounts can cause:

• Nausea and vomiting within 30 minutes
• Severe abdominal pain
• Irregular heartbeat (arrhythmia)
• Low blood pressure
• In extreme cases, cardiac arrest

A documented case from the Centers for Disease Control and Prevention reported hospitalization of three foragers who mistook sea onion for wild garlic. The National Poison Data System recorded 127 sea onion exposure cases between 2018-2022, with 47 requiring intensive care treatment.

Safety Protocols When Encountering Suspect Plants

Follow these evidence-based safety measures when foraging in coastal regions where sea onion grows:

1. Never rely solely on visual identification—always perform the smell test (true onions emit characteristic odor when crushed)
2. Avoid plants with separate leaf and flower growth cycles, a hallmark of sea onion
3. Carry reference photos of both sea onion and local edible varieties
4. When in doubt, leave it out—no foraged plant is worth risking severe poisoning

The University of California Cooperative Extension emphasizes that sea onion poisoning cases peak during spring foraging season when the plant's flower stalk resembles certain edible varieties. Their safety guidelines specifically warn against harvesting any "onion" that lacks the characteristic Allium scent.

What to Do If Poisoning Is Suspected

Immediate action saves lives when sea onion ingestion occurs:

• Contact poison control immediately (1-800-222-1222 in the US)
• Do NOT induce vomiting unless instructed by medical professionals
• Preserve a plant sample for identification
• Monitor for cardiac symptoms while awaiting help

Medical treatment typically involves activated charcoal administration and cardiac monitoring. The UpToDate medical resource confirms that prompt treatment results in full recovery for most cases, while delayed intervention increases fatality risk significantly.

Common Misconceptions About Sea Onion

Several dangerous myths persist about this plant:

• Myth: Cooking destroys the toxins
  Fact: Cardiac glycosides remain stable through cooking
• Myth: Only the bulb is toxic
  Fact: All plant parts contain dangerous concentrations
• Myth: Small amounts provide medicinal benefits
  Fact: Therapeutic use requires precise pharmaceutical preparation under medical supervision

Despite historical use in traditional medicine, modern medical professionals strongly advise against any self-administration due to the narrow therapeutic window between beneficial and toxic doses.

Is sea onion plant poisonous to touch?

The sea onion plant is not typically dangerous to touch, but handling the bulb can cause skin irritation in sensitive individuals. The primary risk comes from ingestion, not skin contact. Always wash hands thoroughly after handling any unidentified plant.

How can I tell sea onion from wild garlic?

Sea onion lacks the distinctive garlic/onion smell of wild garlic. Wild garlic has flat, broad leaves with a strong aroma, while sea onion leaves have no scent. Wild garlic flowers and leaves grow simultaneously, whereas sea onion produces flowers before leaves appear.

What are the first symptoms of sea onion poisoning?

Initial symptoms of sea onion poisoning typically appear within 30 minutes and include nausea, vomiting, abdominal pain, and diarrhea. More severe symptoms like irregular heartbeat, dizziness, and low blood pressure may follow. Seek immediate medical attention if ingestion is suspected.

Can animals eat sea onion plants?

Sea onion is toxic to most animals, including livestock and pets. Cattle and sheep have died from grazing on sea onion in Mediterranean regions. Keep pets away from areas where sea onion grows, as even small ingestions can cause serious illness in dogs and cats.

Is sea squill the same as sea onion?

Yes, sea squill is another common name for the sea onion plant (Drimia maritima). Both names refer to the same toxic species. The term 'squill' comes from the plant's historical medicinal use, while 'sea onion' describes its coastal habitat and onion-like appearance.