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Rudbeckia, Genus, triloba, Species,

Genus & species

brown-eyed susan

Asteraceae

Eastern and central North America, from Ontario south to Florida and west to Colorado

Attracts Pollinators Attracts Butterflies Deer Resistant Drought Tolerant

SunFull Sun – Part Shade

WaterMedium · drought-tolerant

HardinessZones 3–9

Overview

Rudbeckia triloba is the brown-eyed Susan — a tall, bushy, short-lived native perennial that grows 36–60 inches (90–150 cm) tall and produces hundreds of small golden-yellow daisy flowers 1.5 inches (4 cm) across with dark brown-purple raised central cones from August through October. The species name 'triloba' means 'three-lobed', describing the lower leaves, which are divided into three lobes — the upper stem leaves are simple and lance-shaped. The defining characteristic is the sheer number of small flowers: where R. fulgida might produce 20–30 medium flowers, R. triloba produces 200–300+ small flowers per plant, creating a dazzling mass effect like a constellation of golden stars. The small flowers branch from every stem node, covering the upper third of the plant in a dense golden cloud. Short-lived — typically 2–3 years — but self-sows prolifically, maintaining colonies indefinitely. More shade-tolerant than other rudbeckias, growing well in partial shade where R. fulgida would struggle. The tall, bushy growth may need staking or pinching. Dark green foliage. Tolerates clay, drought, and partial shade. Deer avoid the foliage.

Native Range

Rudbeckia triloba is native to eastern and central North America, from Ontario south to Florida and west to Colorado. It grows in open woodlands, meadows, roadsides, and disturbed areas.

Suggested Uses

Used in naturalized plantings, cottage gardens, woodland edges, and meadows. The mass of small flowers creates a dazzling late-season display. More shade-tolerant than other rudbeckias. The self-sowing habit maintains the display without replanting.

How to Identify

Identified by hundreds of small (1.5 inch / 4 cm) golden-yellow daisies with dark raised cones covering the upper plant in a dense cloud, with three-lobed lower leaves and lance-shaped upper leaves. The very small, very numerous flowers are the key trait — no other common rudbeckia produces this quantity. The three-lobed lower leaves confirm the species name.

Appearance

Size & Dimensions

Height3' - 5'

Width/Spread2' - 3'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Flowers: August–October

Summer Fall

Flowering from August through October, approximately 6 weeks. Hundreds of small golden daisies. Late bloom fills the summer-to-fall gap.

Detailed Descriptions

Flower Description

Golden-yellow ray florets with a dark brown-purple raised central cone; smaller and more numerous than other rudbeckias

Foliage Description

Dark green, lower leaves three-lobed, upper leaves lance-shaped

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-10 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 Range5.5 - 7.5 (Acidic to alkaline)

3579

Soil Types

loam clay

Drainageaverage

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Plant in full sun to partial shade. Average to moist soil; tolerates clay and shade. Short-lived — allow self-sowing for colony persistence. Pinch by one-third in early June for shorter growth. Leave standing through winter. Cut to ground in early spring.

Pruning

Pinch by one-third in early June if shorter growth is desired. Cut to ground in late February–March. Allow self-sowing.

Pruning Schedule

Prune: March

early spring

Toxicity

Non-toxic

Related Rudbeckia species