What hardiness zones is Cytisus scoparius suitable for?

Cytisus scoparius is Scotch broom (common broom), an upright deciduous shrub growing 5-10 feet (1.5-3 m) tall and 3-6 feet (0.9-1.8 m) wide with green angular photosynthetic stems. Bright yellow pea-shaped flowers 0.75 inch (2 cm) along the stems in April-May. Small trifoliate leaflets 0.25-0.5 inch (6-13 mm) — the green stems are the primary photosynthetic surface. Black seed pods 1-2 inches (2.5-5 cm) explode when dry, ejecting seeds up to 10 feet (3 m). In the legume family (Fabaceae) — nitrogen-fixing. Native to western and central Europe. Classified as a noxious weed and invasive species in the Pacific Northwest, California, Australia, New Zealand, Chile, and Hawaii — banned from sale in several states. This invasive status is the primary limitation. Produces 10,000-18,000 seeds per year; seeds viable in soil for 30+ years. Thrives in poor sandy soil — excess fertility reduces flowering. Short-lived: 10-15 years. Does not regenerate from old bare wood. Toxic — all parts contain cytisine (a nicotinic alkaloid). Deer-resistant. Zones 5-9. Full sun. Growth rate is fast.

Native Range

Native to western and central Europe. Classified as a noxious weed and invasive species in the Pacific Northwest, California, Australia, New Zealand, and Hawaii.

Suggested Uses

Grown on dry sandy slopes, poor soil sites, and in coastal gardens spaced 3-6 feet (0.9-1.8 m). Classified as invasive in many regions — check local regulations. Not for planting near natural areas. Nitrogen-fixing. Toxic. Deer-resistant. Zones 5-9.

How to Identify

Identified by bright yellow pea-shaped flowers along green angular photosynthetic stems on an upright shrub with small sparse trifoliate leaves. The green angular stems (nearly leafless) and the pea-shaped flowers are diagnostic. Distinguished from Genista (similar yellow pea flowers, but typically lower-growing). In Fabaceae.

Appearance

Size & Dimensions

Height5' - 10'

Width/Spread3' - 6'

Reaches mature size in approximately 3 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~4 weeks

Spring

Mid to late spring (April-May). Bright yellow pea-shaped flowers 0.75 inch (2 cm) along green angular stems. Moderately fragrant (coconut-like). 4 weeks of bloom. Bee- and butterfly-pollinated. Black seed pods 1-2 inches (2.5-5 cm) explode when dry.

Detailed Descriptions

Flower Description

Bright yellow (species), pea-shaped, 0.75 inch (2 cm); some cultivars bicolor yellow-red or cream

Foliage Description

Small trifoliate leaflets 0.25-0.5 inch (6-13 mm) on green angular photosynthetic stems — the stems are the primary photosynthetic surface (leaves are small and sparse)

Growing Conditions

Sun Requirements

Full Sun

Requires 6-10 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 Range5.0 - 7.0(Neutral)

357912

Soil Types

sand loam

Drainagewell drained

Water & Climate

Water Needs

Very Low

Frost Tolerance

hardy

Time to Maturity

1-2 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Full sun (6+ hours). Well-drained poor sandy soil pH 5.0-7.0 — excess fertility reduces flowering. Classified as invasive in many regions — check local regulations before planting. Remove spent flowers to reduce seed production. Do not cut into old bare wood. Toxic (cytisine). Short-lived (10-15 years). Deer-resistant. Zones 5-9.

Pruning

Prune lightly after flowering (May-June) — remove spent flowers and shorten current season's growth by 1/3. Do not cut into old bare wood — it will not regenerate. The shrub becomes leggy and bare at the base with age. Short-lived (10-15 years) — plan for replacement.

Pruning Schedule

late spring

Maintenance Level

low

⚠️ Toxicity Warning

Toxic to pets and humans