Sea Squill (Drimia maritima)

Sea squill is a flowering perennial that grows from a bulb. In the fall, the tall leaves die back and make way for the flower spike of red or white clustered petals. This plant is poisonous and has been used in the making of rat poison.

I. Appearance and Characteristics 

Drimia maritima (syn. Urginea maritima) is a species of flowering plant in the family Asparagaceae, subfamily Scilloideae (formerly the family Hyacinthaceae). This species is known by several common names, including squill, sea squill, sea onion, and maritime squill. It may also be called red squill, particularly a form which produces red-tinged flowers instead of white. It is native to southern Europe, western Asia, and northern Africa.

This plant grows from a large bulb which can be up to 20 cm (7.9 in) wide and weigh 1 kg (2.2 lb). Bailey reported weights of up to fifteen pounds (seven kilograms), probably referring to a clump. Several bulbs may grow in a clump and are usually just beneath the surface of the soil. In the spring, each bulb produces a rosette of about ten leaves each up to a meter long. They are dark green in color and leathery in texture. They die away by fall, when the bulb produces a tall, narrow raceme of flowers.

This inflorescence can reach 1.5–2 m (4 ft 11 in – 6 ft 7 in) in height. The flower is about 1.5 cm (0.59 in) wide and has six sepals each with a dark stripe down the middle. The petals are white, with the exception of those on the red-flowered form. The fruit is a capsule up to 1.2 cm (0.47 in) long.

This plant often grows in rocky coastal habitat, especially in the Mediterranean Basin, where it is common. It occurs in many other types of habitat, except for the driest deserts. It can grow in the open and also in very shady areas. Its habit of producing leaves in the spring and flowers in the fall is an adaptation to the Mediterranean climate of its native range, where the summers are hot and dry.

This species has two different pollination syndromes, entomophily and anemophily; it is pollinated by insects and wind. Insect pollinators include the western honey bee (Apis mellifera), the Oriental hornet (Vespa orientalis), and the paper wasp species Polistes gallicus.

II. How to Grow and Care

Sea squill is known for its resilience and low-maintenance requirements. A special care point for sea squill is to avoid waterlogging, as this can lead to root rot. Sea squill generally prefers full sun exposure and can handle neglect better than over-attention. With these simple but crucial care considerations, sea squill can be a straightforward addition to any garden.

Sunlight

Sea squill thrives in full sun exposure, which is critical for its robust growth and abundant flowering. These optimal conditions ensure vibrant health and energy for the plant to produce its striking blooms. While sea squill is capable of light adaptability, insufficient sunlight may lead to subdued flowering and potential health issues. For outdoor cultivation, sea squill should be planted in an area where it receives unhindered daylight. Indoor growers must place it in a location with ample direct light, like a south-facing window, to mimic its natural habitat. The plant’s resilience in the face of varying light levels is significant, yet aligning with its preference for full sun will promote an ideal growth and flowering cycle.

Watering

Native to rocky coastlines, sea squill thrives in environments with well-drained soil and can tolerate periods of dryness, indicative of its drought-resistant nature. Watering every week will maintain its health without over-saturating the soil. As an outdoor plant often found in coastal regions, sea squill has adapted to absorb moisture efficiently during sparse rainfall, making it suitable for xeriscaping or rock gardens. Its bulbous structure is a testament to its ability to store water, allowing it to survive where rain is infrequent.

Soil

The plant thrives in well-draining soil and requires minimal watering, especially since it is drought-tolerant.

Fertilizing

For sea squill’s robust growth and blooming, apply balanced nutrition fertilizers biannually, complemented with high phosphorus types during active growth to enhance flowering. Use manufacturer-recommended quantities, avoiding over-fertilization, which can damage sea squill. Seasonal adjustments are key; increase phosphorus in spring for vigorous blooms, tapering in dormant periods. Water well post-fertilization to aid nutrient absorption. Wear gloves; sea squill is toxic. This regime ensures sea squill’s vitality and bloom, catering to both novice and seasoned gardeners.

Propagation

Endemic to the Mediterranean, sea squill is a perennial bulbous plant known for its tall flowering stalks and medicinal uses. To propagate sea squill effectively, dividing the plant’s bulb clusters is a suitable method. Carefully separate the offsets from the mature bulb during its dormant period. These separated offsets can then be replanted in well-draining soil, positioned to accommodate their size, and provided with sufficient water to establish roots. This approach nurtures new growth, maintaining the durability and charm of sea squill.

Transplanting

Autumn is the optimal time to transplant sea squill, encouraging robust growth with mild temperatures and less stress on the plant. Choose a sunny spot with well-draining soil. Only transplant when truly needed to maintain sea squill’s vitality.

Repotting

Repot sea squill every 2-3 years, best post-bloom when dormant to accommodate its robust bulb and growth cycle. Choose a deep container for its extensive root system. Post-repotting, sea squill benefits from slightly increased watering and indirect light to re-establish. Remember, sea squill tolerates neglect but thrives with care.

III. Uses and Benefits 

• Ornamental uses

The tall inflorescences are used as cut flowers in floristry.

• Medicinal uses

This species has been used as a medicinal plant since ancient times. It is noted in the Ebers Papyrus of the 16th century BC, one of the oldest medical texts of ancient Egypt. Pythagoras wrote about it in the 6th century BC. Hippocrates used it to treat jaundice, convulsions, and asthma. Theophrastus was also familiar with it. Its primary medicinal use was as a treatment for edema, then called dropsy, because of the diuretic properties of the cardiac glycosides. A solution of sea squill and vinegar was a common remedy for centuries. The plant is also used as a laxative and an expectorant.

• Poison

The plant has also been used as a poison. It is very bitter, so most animals avoid it. Rats, however, eat it readily, and then succumb to the toxic scilliroside. This has made the plant a popular rodenticide for nearly as long as it has been in use as a medicine. The bulbs are dried and cut into chips, which can then be powdered and mixed with rat bait. The plant was introduced as an experimental agricultural crop in the 20th century primarily to develop high-toxicity varieties for use as rat poison. Interest continued to develop as rats became resistant to coumarin-based poisons.

It has also been tested as an insecticide against pests such as the red flour beetle (Tribolium castaneum).

• Spiritual use

Pythagoras and Dioscorides hung the bulbs with sprouted leaves outside the door in spring as protection against evil spirits. The bulbs are still gathered and displayed in the winter as part of Greek Christmas and new year’s traditions.