Nineleaf Biscuitroot (Lomatium triternatum)

Plant Snapshot

Common Name: Nineleaf Biscuitroot
Latin Name: Lomatium triternatum
Hardiness Zones: USDA zones 4–8 based on native range and typical cold tolerance. In colder zones plants may die back to the crown. In warmer zones growth may be reduced to a summer dormant period.
Typical Height: 4–20 in (10–50 cm) tall.
Typical Spread: 6–16 in (15–40 cm) wide in clumps.
Bloom Period: Spring to early summer in the Northern Hemisphere.
Soil Preferences: Well drained rocky or sandy soils. Tolerates poor and shallow soils. Avoid heavy clay or waterlogged sites which can cause crown rot.
Light Preferences: Full sun to light shade. Best flowering and form in full sun.
Toxicity: Roots were eaten historically by some Indigenous peoples but confirm species before use. Some Lomatium species can cause skin irritation in sensitive individuals. Pet toxicity is not well documented so avoid feeding to animals.
Propagation: By seed and by dividing crowns. Seed germination benefits from cold moist stratification and sowing in spring or fall.

Key Facts

Native perennial herb of western North America.
Member of the carrot family Apiaceae.
Leaves are divided and typically appear as three ternate leaflets totaling nine leaflets.
Produces yellow umbels of flowers in spring.
Prefers well drained rocky or sandy sites.
Attractive to bees and other pollinators.
Roots were used as a food source by some Indigenous peoples but verify identity before use.

Nineleaf Biscuitroot is a low perennial herb in the carrot family native to western North America. It has finely divided leaves that commonly form nine leaflets and bears yellow umbels in spring, making it a useful choice for sunny, well drained rocky spots that attract pollinators.

Identification

Leaves are divided into three ternate leaflets that commonly total nine leaflets, which gives the plant its common name. Plants produce flat yellow umbels of small flowers in spring and stand about 4 to 20 inches tall, remaining a compact, herbaceous presence in native plantings.

Best uses and where to grow

Use Nineleaf Biscuitroot in rock gardens, dry slopes, native meadow accents and pollinator patches where poor, well drained soils exist. It performs best in full sun to light shade and will not thrive in waterlogged or heavy clay sites, so place it where drainage is reliable.

Planting time and establishment

Sow seed in spring or fall with appropriate cold moist stratification or plant divisions in early spring. Flowering normally occurs in spring to early summer, so establish plants a season before you expect full bloom for best display and crown development.

Soil, light and watering

Prefers well drained rocky or sandy soils and tolerates low fertility. Give full sun to light shade for best flowering and form. Water sparingly once established; persistent wet soil can lead to crown rot and poor longevity.

After flowering and seasonal care

Plants typically die back to the crown after the growing season in colder areas and may enter a summer dormant period in warmer climates. Remove dead foliage in late season for tidiness and divide crowns in early spring if clumps need rejuvenation.

Propagation

Propagate by seed or by dividing crowns. Seed germination is improved by cold moist stratification and seeds are often sown in spring or fall. Established clumps can be split in early spring to produce additional plants.

Naturalizing and control

When planted in suitable dry, rocky conditions Nineleaf Biscuitroot establishes into persistent patches over time. Limit unwanted expansion by removing stray seedlings or by dividing and replanting crowns to keep clusters contained.

Frequently asked questions

How fast does Nineleaf Biscuitroot grow?: Growth is slow to moderate. Established plants reach about 4 to 20 inches tall and fill in their place over a few seasons.
When does Nineleaf Biscuitroot bloom?: Blooming occurs in spring to early summer, generally March through June in the Northern Hemisphere with local variation by climate and elevation.
What soil and light does it need?: Choose well drained rocky or sandy soil in full sun to light shade for best flowering and plant health.
How should I propagate it?: Use seed with cold moist stratification or divide crowns in early spring to propagate established plants.
Does it attract pollinators?: Yes. The yellow umbels are attractive to bees and other spring pollinators.