Dirca spp.

leatherwood

Thymelaeaceae North America

Attracts Pollinators Deer Resistant

Native to North America

SunPart Shade – Full Shade

WaterMedium

HardinessZones 4–8

Overview

Dirca spp. is a small genus of about four species of deciduous shrubs in the family Thymelaeaceae, native to North America. Plants grow slowly into rounded, open shrubs 3-6 feet (0.9-1.8 m) tall, occasionally taller, with jointed twigs and tough, pliable bark that can be bent and knotted without breaking. Small pale yellow tubular flowers hang in clusters of two to four along the bare stems in early spring, before the leaves expand. The alternate leaves are oval, 1.5-3 inches (4-8 cm) long, soft light green in summer and clear yellow in autumn. Pale green to reddish oval fruits follow, ripening in late spring to summer. D. palustris, eastern leatherwood, ranges across eastern North America, while D. occidentalis is confined to the San Francisco Bay area of California. Plants grow in shaded, moist woodland and need cool, humus-rich soil. The bark and fruit contain irritant compounds that can blister skin and cause stomach upset if eaten.

Native Range

Dirca spp. is native to North America, with D. palustris widespread in moist deciduous woodland across the eastern United States and Canada, and D. occidentalis restricted to the San Francisco Bay region. Other species occur in the south-central United States and Mexico.

Suggested Uses

Grown in shaded woodland and native plant gardens, in shrub borders under high tree canopy, and in naturalised understory plantings. The early flowers and yellow autumn leaves suit cool, moist shade gardens.

How to Identify

Recognised by jointed, very flexible twigs with tough bark, and by clusters of small pale yellow tubular flowers that open along bare stems in early spring before the leaves. Leaf scars nearly surround the buds, and the soft oval leaves turn yellow in autumn. The pliable knottable bark is a reliable field check for the genus.

Appearance

Size & Dimensions

Height3' - 6'

Width/Spread3' - 6'

Reaches mature size in approximately 15 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~3 weeks

Spring

Flowering occurs in early spring, often March to April, when pale yellow tubular flowers hang in small clusters along the leafless stems. The flowers open early, before most woodland shrubs leaf out. Pale green to reddish fruits follow and ripen by early summer.

Detailed Descriptions

Foliage Description

light green, yellow in autumn

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Tolerates up to 4 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 - 7.0(Neutral)

357912

Soil Types

loam

Drainagewell drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

10-15 years

Care & Maintenance

Care Guide

Dirca spp. grows in part to full shade in cool, moist, humus-rich, well-drained woodland soil, matching its native understory habitat. Plants are slow-growing and long-lived, and grow poorly on hot, dry, or compacted sites. Steady moisture and a mulch of leaf litter support the shallow roots, while full sun and drought cause leaf scorch and dieback. The genus is cold-hardy through about USDA zones 4 to 8 for the eastern species, with the California species suited to milder zones. Transplanting is done while plants are small, because established shrubs move poorly. Little feeding is needed in soils already rich in organic matter.

Pruning

Little pruning is needed because plants grow slowly into a naturally rounded shape. Dead or damaged twigs can be removed after flowering. Hard pruning is rarely warranted and slow to be covered by new growth.

Pruning Schedule

late spring