San Nicolas Island biscuitroot (Lomatium insularum)

San Nicolas Island biscuitroot

Lomatium insularum

A rare and resilient perennial herb clinging to coastal bluffs, embodying the rugged beauty of island isolation.

Requires full sun, typical of open coastal bluffs.
1/week
Challenging
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Plant Needs

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Sunlight Requires full sun, typical of open coastal bluffs.
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Watering Drought tolerant once established; requires well-draining soil and minimal supplemental summer water.
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Temperature Prefers mild, frost-free Mediterranean coastal climates.
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Characteristics

  • Leaves: Basal, highly dissected, fleshy, glaucous (gray-green), pinnately compound;
  • Flowers: Small, yellow, arranged in compound umbels typical of the carrot family;
  • Fruit: Flattened schizocarps with lateral wings, adapted for wind dispersal;
  • Root: Thick, deep taproot adapted to rocky, dry coastal soils.
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Care Guide

Watering

Water sparingly, allowing soil to dry out completely between waterings.

Fertilization

Apply a very light organic topdressing if soil is extremely poor.. Minimal fertilization required; adapted to nutrient-poor soils.

Crushed Eggshells:Rinse, dry, and crush eggshells into a fine powder. Sprinkle sparingly around the base to provide slow-release calcium without overloading the soil with nitrogen.
Pruning
  • Remove dead or yellowing basal leaves to maintain appearance;
  • Deadhead spent flower stalks if seed collection is not desired;
  • Avoid heavy pruning as the plant relies entirely on its basal rosette.
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Toxicity

Warning: this plant may be toxic.

Pets & Humans

Pets: No known toxicity to cats.

Humans: No known toxicity; many related species are edible, but caution is advised due to highly toxic look-alikes in the family.

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Garden Uses & Culture

Culture: While this specific island endemic is rare, the genus Lomatium holds significant historical importance in Western North America, where indigenous peoples relied heavily on the starchy taproots of various species as a staple winter food, commonly known as biscuitroot.

Usage: Primarily used in ecological restoration and conservation on the Channel Islands; rarely cultivated in standard gardens.