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Rudbeckia hirta 'Prairie Sun' (Prairie Sun Rudbeckia)
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Rudbeckia hirta 'Prairie Sun'

Prairie Sun Rudbeckia

Central and eastern North America (species range)

At a Glance

HabitUpright
FoliageDeciduous
Height30-36 inches (76-91 cm)
Width18-24 inches (45-60 cm)
Maturity1 years

Growing Zones

USDA Hardiness Zones

3 - 9
These zones indicate the coldest temperatures this plant can typically survive.
What's my zone? →
Frost Tolerancehardy

Overview

Rudbeckia hirta 'Prairie Sun' is a short-lived perennial or biennial gloriosa daisy reaching 30-36 inches (76-91 cm) tall and 18-24 inches (45-60 cm) wide. Stems are stiff, erect, and branched in the upper third, covered in coarse white hairs. Lance-shaped basal leaves are 4-6 inches (10-15 cm) long, hairy, and mid-green; stem leaves reduce in size up the stem. Flowers are 4-5 inches (10-13 cm) across, with golden-orange petal tips fading to lemon-yellow at the base of each ray, surrounding a domed, light green center disk; this disk does not turn dark brown as in many R. hirta cultivars. Bloom occurs late June through first frost; deadheading prolongs flowering. Plants behave as annuals in zones 3-4 and as short-lived perennials (2-3 years) in zones 5-9. Self-seeding is moderate; volunteer seedlings often revert to species-type form with brown disks. Powdery mildew develops on lower leaves in late summer and may cause early leaf drop. Slugs feed on emerging spring growth in damp gardens; aphids may colonize flower buds.

Native Range

Rudbeckia hirta is native to central and eastern North America, ranging from the Great Plains east to the Atlantic coast and from southern Canada south to northern Mexico. It grows in prairies, open woodlands, fields, and roadsides on a range of soils. 'Prairie Sun' is a 2003 All-America Selections winner derived from R. hirta breeding.

Suggested Uses

Used in mid-border perennial plantings, cutting gardens, and naturalistic prairie plantings at 18-24 inch (45-60 cm) spacing. Long stems make it suitable for cut-flower production; vase life averages 7-10 days when stems are cut early in the morning. Container culture is feasible in 3-gallon (11 L) or larger pots; plants typically reseed themselves but seedlings may revert to species coloration.

How to Identify

Erect coarse-haired stems 30-36 inches (76-91 cm) tall with lance-shaped basal leaves 4-6 inches (10-15 cm) long. Flowers 4-5 inches (10-13 cm) across with golden-orange petal tips, lemon-yellow petal bases, and a light green domed center disk. The green center separates 'Prairie Sun' from yellow-rayed cultivars with brown or black disks; the bicolored petals separate it from solid-yellow 'Indian Summer'.

Appearance

Size & Dimensions

Height2'6" - 3'
Width/Spread1'6" - 2'

Reaches mature size in approximately 1 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~16 weeks
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Late June through first frost in zones 5-7, mid June through October in zones 8-9, and early July through first frost in zones 3-4. Individual flowers last 2-3 weeks; deadheading triggers continuous bud production through the growing season. Plants started indoors in late winter flower the same year as a 12-week summer annual; outdoor sowings flower in their second year.

Detailed Descriptions

Flower Description

golden-orange petal tips fading to lemon-yellow with a light green domed center disk

Foliage Description

mid-green; hairy

Growing Conditions

Sun Requirements

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 Range6.0 - 7.5(Neutral)
357912
Soil Types
Drainagewell drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

Flowers from seed in 12-14 weeks under summer conditions

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Seeds are surface-sown indoors 6-8 weeks before last frost or direct-sown in late spring after soil reaches 70°F (21°C); germination takes 7-14 days at 70-75°F (21-24°C). Plants are spaced 18-24 inches (45-60 cm) apart in full sun. Established plants tolerate 2-3 weeks of dry soil but flower size decreases under drought. A balanced 10-10-10 fertilizer is applied at half strength once at planting; supplemental feeding is unnecessary on average garden soils. Powdery mildew appears on lower leaves in late summer; affected leaves are removed and overhead watering is reduced. Aphids may colonize flower buds in spring and are dislodged with a forceful water spray. Plants are typically replaced every 2-3 years as flowering declines.

Pruning

Spent flowers are cut just below the bloom every 7-10 days to maintain continuous flowering and to reduce self-seeding. Stems are cut to ground level after the first hard frost in autumn or in early spring before new growth emerges. No structural pruning is required.

Pruning Schedule

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fall

Maintenance Level

low

Container Growing

✓ Suitable for container growing

Minimum container size: 3 gallons

⚠️ Toxicity Warning

Non-toxic