Prairie Sun

Family: Asteraceae Flower

Planting Schedule

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Sun-warmed petals unfurl in a golden halo around a velvety, inky center—Prairie Sun Black-eyed Susan brings bold, radiant color to the garden from early summer into fall.

The blooms are richly textured, with sturdy, upright stems that hold their form and a daisy-like presence that feels both lively and refined. Grow it for long-lasting landscape impact, striking cut-flower charm, and effortless pollinator appeal that turns sunny borders into a living tapestry.

Light: Full SunMaturity: 90 DaysHabit: Upright

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Prairie Sun Planting Dates by USDA Zone

Estimated US hardiness-zone windows for sow, transplant, and harvest. Enter a US ZIP above for exact local dates, or open a zone below.

Zone	Start Indoors	Sow / Transplant	Harvest
Zone 1a	Protected Environment Only
Zone 1b	Protected Environment Only
Zone 2a	Direct Sow	May 25th	Aug 23rd – Aug 29th
Zone 2b	Direct Sow	May 15th	Aug 13th – Aug 25th
Zone 3a	Direct Sow	May 15th	Aug 13th – Sep 1st
Zone 3b	Direct Sow	May 19th	Aug 17th – Sep 21st
Zone 4a	Direct Sow	May 15th	Aug 13th – Sep 24th
Zone 4b	Direct Sow	May 13th	Aug 11th – Sep 27th
Zone 5a	Direct Sow	May 8th	Aug 6th – Sep 30th
Zone 5b	Direct Sow	May 4th	Aug 2nd – Oct 5th
Zone 6a	Direct Sow	May 1st	Jul 30th – Oct 10th
Zone 6b	Direct Sow	Apr 25th	Jul 24th – Oct 16th
Zone 7a	Direct Sow	Apr 20th	Jul 19th – Oct 20th
Zone 7b	Direct Sow	Apr 10th	Jul 9th – Oct 28th
Zone 8a	Direct Sow	Apr 1st	Jun 30th – Nov 5th
Zone 8b	Direct Sow	Mar 23rd	Jun 21st – Nov 12th
Zone 9a	Direct Sow	Mar 6th	Jun 4th – Nov 26th
Zone 9b	Direct Sow	Feb 9th	May 10th – Dec 9th
Zone 10a	—	Oct 1st	Dec 30th – Feb 28th
Zone 10b	—	Oct 1st	Dec 30th – Feb 28th
Zone 11a	—	Oct 1st	Dec 30th – Feb 28th
Zone 11b	—	Oct 1st	Dec 30th – Feb 28th
Zone 12a	—	Oct 1st	Dec 30th – Feb 28th
Zone 12b	—	Oct 1st	Dec 30th – Feb 28th
Zone 13a	—	Oct 1st	Dec 30th – Feb 28th
Zone 13b	—	Oct 1st	Dec 30th – Feb 28th

Crop Details

Trait	Value
Days to Maturity	90
Sun Requirements	Full Sun
Growth Habit	Upright
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	70
Min Soil Temp (°F)	55
Min Night Temp (°F)	40
Harden Off (days)	Not Required

Frequently Asked Questions

How do I prevent and treat powdery mildew on Rudbeckia hirta (Prairie Sun)?

Rudbeckia hirta commonly gets powdery mildew in late summer, especially when nights are humid and airflow is poor. At the first white, dusty patches, remove the worst leaves and water at the soil line (not overhead), then improve spacing and airflow around plants. If it keeps spreading, spray with a labeled fungicide for powdery mildew, following the label’s timing and reapplication interval.

How often should I water Prairie Sun Rudbeckia hirta during the main growing phase?

During active growth (after establishment), keep the soil consistently evenly moist but never soggy—aim for about 1 inch of water per week from rain and irrigation combined. Water deeply when the top 1–2 inches of soil feel dry to the touch, and let excess water drain; Rudbeckia hirta dislikes waterlogged soil. Once plants are established, you can stretch watering a bit, but don’t let them dry out completely during bloom.

How can I tell when Prairie Sun (Rudbeckia hirta) is ready to harvest?

For cut flowers, harvest when the central disk florets are fully developed and the bright yellow-orange rays are at their peak color, usually around day 90. Choose blooms that are just starting to open (fresh and firm) rather than those with browned, dried centers. If you’re harvesting seed, wait until the flower heads turn dark and the seeds look mature, then cut heads before they fully shed.