Osmorhiza berteroi (mountain sweet cicely)

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Osmorhiza, Genus, spp., Multiple species,

Genus
Multiple species

sweet cicely

Apiaceae North America and eastern Asia

Attracts Pollinators Attracts Butterflies Fragrant (moderate)

SunPart Shade – Full Shade

WaterMedium

HardinessZones 3–8

Overview

Osmorhiza is a genus of about ten species of perennial herbs in the carrot family (Apiaceae), native to the woodlands of North America and eastern Asia. Plants grow 12 to 36 inches (30 to 90 cm) tall and 12 to 24 inches (30 to 60 cm) wide from a thick, anise-scented root, with soft, bright green, fern-like leaves divided into toothed leaflets. Small white to greenish-white flowers are borne in loose, open, compound umbels held above the foliage on slender stalks in spring and early summer. The flowers give way to narrow, club-shaped fruits about 0.5 to 0.9 inch (12 to 22 mm) long, tipped with stiff bristles that cling to clothing and animal fur and carry the seed to new ground. Crushed roots and foliage release a sweet anise or licorice scent, and several species have been used as flavoring and food. The foliage and flower form resemble those of highly toxic relatives such as poison hemlock and water hemlock, which grow in similar habitats. Plants grow in moist, shaded, humus-rich woodland soils and spread by seed into open ground, but they decline in hot, dry, or sunny sites.

Native Range

Osmorhiza ranges across temperate North America, from Canada through the United States into Mexico, with additional species in eastern Asia and South America. The genus is widespread in moist deciduous and mixed woodlands.

Suggested Uses

Osmorhiza is used in woodland and shade gardens, native plantings, and naturalized woodland edges, where its ferny foliage and anise scent fill shaded ground. It supports early-season pollinators in spring. The clinging fruits and ready self-sowing suit informal rather than tidy plantings.

How to Identify

Identify Osmorhiza by its soft, fern-like leaves divided into toothed leaflets and its loose, open umbels of small white to greenish flowers. The narrow, club-shaped fruits, 0.5 to 0.9 inch (12 to 22 mm) long, are tipped with bristles that cling to fabric and fur. Crushed roots and stems smell strongly of anise. The plant resembles poison hemlock and water hemlock, so identification depends on the scent and the bristled fruits.

Appearance

Size & Dimensions

Height1' - 3'

Width/Spread1' - 2'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~4 weeks

Flowers: April–June

Spring Summer

Osmorhiza blooms in spring and early summer, mainly April through June, with airy umbels of small flowers opening above the foliage. Flowering lasts about three to four weeks. The bristly fruits develop through summer and detach readily by autumn.

Detailed Descriptions

Flower Description

white to greenish-white

Foliage Description

bright green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Requires 2-6 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.5 (Acidic to alkaline)

3579

Soil Types

loam

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Care & Maintenance

Care Guide

Osmorhiza grows in part to full shade in moist, humus-rich, well-drained woodland soil. Plants need steady moisture during the growing season and decline in hot, dry, or fully exposed sites. The genus self-sows freely, with bristly fruits spread by animals and clothing, and can naturalize through a shaded garden. Plants are grown from fresh seed sown in fall, as the seed needs cold winter conditions to germinate, and are slow to establish from transplants. Little fertilizer is needed in rich woodland soil. Foliage dies back to the root in late summer and through winter.

Pruning

Osmorhiza needs no pruning. Spent flower stems can be removed before the fruits ripen to limit self-sowing. Dead foliage is cleared in late summer or fall as the plant goes dormant.

Toxicity

Non-toxic

Related Osmorhiza species