🌸 Cosmos
Cosmos bipinnatus
The easiest flowers you'll ever grow — sow, ignore, enjoy.
Sun
Full sun, 6+ hrs
Days to harvest
60–75 days from seed
Spacing
12–18 inches apart
Soil pH
6.0–7.0
How to grow
Direct sow after frost danger — in Florida, fall sowing gives spring blooms and spring sowing gives summer-fall blooms. It thrives on neglect and poor soil; rich soil grows leaves, not flowers. Self-seeds freely, so plant once and enjoy the volunteers forever.
Water & feeding
Drought-tolerant; water seedlings until established, then basically forget it. Overwatering = floppy plants.
Common problems
- Floppy stems in rich soil or shade
- Powdery mildew in humid, crowded stands
- Aphids on buds (usually minor)
Harvest
Cut early and often — cosmos is a cut-and-come-again machine. Deadhead or it sets seed and quits blooming.
Nerdy fact: Cosmos is in the aster family, so each 'flower' is actually dozens of tiny florets — the showy petals are just ray florets advertising to pollinators. It's a composite head running a marketing department.