Denver Daisy

Black-eyed Susan

Zone 9b Save Garden

🌱 75d to harvest Clumping

Velvety, inky-black centers glow like polished jet against warm golden petals, creating a sunlit bloom that feels almost luminous…

Crop Dates

Milestone	Date
Start Indoors	Dec 29th
Last Frost	Feb 9th
Transplant / Sow Outdoors	Feb 9th
Harvest Begins	Apr 25th
Harvest Ends	Dec 9th

Crop Details

Trait	Value
Days to Maturity	75
Sun Requirements	Full Sun
Growth Habit	Clumping
Support Needed	None
Planting Depth	Normal
Germination Temp (°F)	70
Min Soil Temp (°F)	60
Min Night Temp (°F)	45
Harden Off (days)	7

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Frequently Asked Questions

What pest or disease problem is most common on Rudbeckia hirta (Denver Daisy), and what should I do about it?

Rudbeckia hirta is prone to powdery mildew, especially when nights are cool and air movement is limited. Remove heavily infected leaves early, water at the soil line (not overhead), and space plants so foliage dries quickly. If mildew keeps returning, treat with a labeled fungicide made for powdery mildew according to the label directions.

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

During active growth and bud formation, keep the soil evenly moist but not soggy—water deeply about 1–2 times per week depending on rainfall. Let the top 1 inch of soil dry before watering again, because saturated soil encourages root problems and leaf diseases. Once established, Denver Daisy tolerates some drought, but extended dryness can reduce bloom size and duration.

How can I tell when Denver Daisy (Rudbeckia hirta) is ready to harvest for flowers?

Harvest when the flower heads have fully opened and the dark central disk florets are mature, while the outer ray petals still look fresh and crisp. For cut flowers, snip stems early in the morning and harvest individual heads that are at full bloom rather than those with browning centers. With regular deadheading, new blooms should form, and you can keep harvesting throughout the season until plants start to decline.

Velvety, inky-black centers glow like polished jet against warm golden petals, creating a sunlit bloom that feels almost luminous at dusk. Denver Daisy forms sturdy clumps of daisy-like flowers with a crisp, slightly ruffled texture that holds its presence beautifully in the garden. Grow it for long-lasting ornamental color in beds and borders, where its bold contrast makes every planting feel confidently finished.

Sowing Tips

Transplant Conditions

Wait until soil reaches 60°F and nights stay above 45°F before moving outdoors. Harden off for 7 days first.

Expert Note

Start indoors early for the first bloom year (if desired), but in many climates Denver Daisy also performs well from direct sow once nights are consistently mild.