Cosmos Sensation

Planting Schedule

Provide your location or planting zone to unlock dates and add Cosmos Sensation to a garden.

Feathery, cloudlike blooms in a riot of warm pinks, rosy reds, and crisp whites open to a silky, petal-soft presence that feels almost luminous in the garden.

Cosmos Sensation carries a lively, upright branching habit and produces abundant flowers with a delicate, airy texture—ideal for long-lasting color and fresh bouquets. Grow it for a breezy summer spectacle that keeps flowering as the days lengthen, turning beds and borders into a painterly swirl of motion.

Light: Full SunMaturity: 60 DaysHabit: Upright

Botanical illustration of Cosmos Sensation

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Cosmos Sensation 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	Direct Sow	Jun 1st	Jul 31st – Aug 1st
Zone 2a	Direct Sow	May 25th	Jul 24th – Aug 29th
Zone 2b	Direct Sow	May 15th	Jul 14th – Aug 25th
Zone 3a	Direct Sow	May 15th	Jul 14th – Sep 1st
Zone 3b	Direct Sow	May 19th	Jul 18th – Sep 21st
Zone 4a	Direct Sow	May 15th	Jul 14th – Sep 24th
Zone 4b	Direct Sow	May 13th	Jul 12th – Sep 27th
Zone 5a	Direct Sow	May 8th	Jul 7th – Sep 30th
Zone 5b	Direct Sow	May 4th	Jul 3rd – Oct 5th
Zone 6a	Direct Sow	May 1st	Jun 30th – Oct 10th
Zone 6b	Direct Sow	Apr 25th	Jun 24th – Oct 16th
Zone 7a	Direct Sow	Apr 20th	Jun 19th – Oct 20th
Zone 7b	Direct Sow	Apr 10th	Jun 9th – Oct 28th
Zone 8a	Direct Sow	Apr 1st	May 31st – Nov 5th
Zone 8b	Direct Sow	Mar 23rd	May 22nd – Nov 12th
Zone 9a	Direct Sow	Mar 6th	May 5th – Nov 26th
Zone 9b	Direct Sow	Feb 9th	Apr 10th – Dec 9th
Zone 10a	—	Oct 1st	Nov 30th – Feb 28th
Zone 10b	—	Oct 1st	Nov 30th – Feb 28th
Zone 11a	—	Oct 1st	Nov 30th – Feb 28th
Zone 11b	—	Oct 1st	Nov 30th – Feb 28th
Zone 12a	—	Oct 1st	Nov 30th – Feb 28th
Zone 12b	—	Oct 1st	Nov 30th – Feb 28th
Zone 13a	—	Oct 1st	Nov 30th – Feb 28th
Zone 13b	—	Oct 1st	Nov 30th – Feb 28th

Crop Details

Trait	Value
Days to Maturity	60
Sun Requirements	Full Sun
Growth Habit	Upright
Support Needed	None
Planting Depth	Surface
Germination Temp (°F)	70
Min Soil Temp (°F)	55
Min Night Temp (°F)	50
Harden Off (days)	7

Frequently Asked Questions

How do I prevent and treat powdery mildew on Cosmos (Cosmos bipinnatus) like 'Sensation'?

Powdery mildew shows up as a white, talc-like coating on leaves and spreads quickly in warm, still air. Start by thinning so plants have airflow, water at the base (not over the foliage), and remove the most affected leaves early. If it keeps spreading, spray a labeled potassium bicarbonate or horticultural sulfur product per the label directions, avoiding application during very hot afternoons.

How often should I water Cosmos (Cosmos bipinnatus) during the main growing phase (after seedlings establish)?

After establishment, keep the soil evenly moist but not soggy—water when the top 1–2 in (2–5 cm) of soil feels dry. During active flowering, this usually means deep watering about 1–2 times per week depending on heat and soil, with more frequent watering in sandy beds. Cosmos tolerates some dryness, but long dry spells can reduce flower production, so aim for consistent moisture during bloom.

When are Cosmos (Cosmos bipinnatus) 'Sensation' ready to harvest for cut flowers?

Harvest when the ray petals are fully expanded and the center disk looks developed but not dried and brown—this is typically around 60 days from sowing/early germination depending on conditions. Cut in the morning, and re-cut stems just above a leaf node to encourage branching and additional blooms. Expect the most productive flush when you harvest regularly, before flowers begin setting seed.