Cosmos bipinnatus 'Sensation Mix'
This is a tall mix of single‑flowered cosmos with ferny foliage and classic daisy heads in pink, red, and white. It stands out for height and long stems that suit cutting. It performs best in full sun with well‑drained soil and modest fertility. It flowers through summer to frost in most of North America. Growth can slow during stretches of extreme heat and humidity. Plants grow as frost‑tender annuals and may self‑seed in mild sites. The airy habit fills borders and meadows without crowding.
At‑a‑glance
Group/Class: Sensation Series; annual cosmos
Height × spread: 36 to 48 in (90 to 120 cm) × 20 to 40 in (50 to 100 cm)
Bloom window: summer to frost
Color & flower form: single daisies in pink, red, and white; 3 to 4 in heads
Fragrance: 0 none
USDA hardiness: grown as annual in all zones; frost tender
Breeder / Year / Origin: unknown
Cut‑flower notes: moderate stem strength; harvest at cracking bud; typical vase life 4 to 7 days with preservative and cool conditioning.
Pet safety: safe; generally non‑toxic to pets; ingestion may cause mild stomach upset.
How it differs
- Taller than many cosmos cultivars with stems to about 4 ft.
- Larger single blooms compared with dwarf and double forms.
- Open, branching habit that fills space lightly.
- More likely to need staking in windy gardens.
Strengths
- Long bloom from early summer to frost.
- Reliable in average garden soils with good drainage.
- Nectar‑rich flowers for pollinators.
- Good for cutting and informal borders.
Care in one minute
- Choose full sun with at least 6 hours of direct light.
- Provide well‑drained soil with low to moderate fertility and neutral to slightly alkaline pH.
- Water to establish then water deeply but infrequently; avoid soggy soil.
- Do not over‑fertilize; high nitrogen can reduce bloom.
- Pinch young plants at 8 to 12 in to branch; stake where windy; deadhead to extend bloom.
- Direct sow after frost or start indoors 4 to 6 weeks before last frost.
Watch‑outs
- Can flop without support in exposed sites.
- Growth may pause in extreme heat and humidity.
- Aphids and slugs can appear; grey mold in prolonged wet.
- Excess fertilizer can reduce bloom and increase foliage.
Best uses (tags)
cutting; borders; meadows; pollinators; heat‑tolerant
Provenance note
Sensation is a recognized series of Cosmos bipinnatus with tall, single‑flowered selections offered widely; detailed breeding origin is not stated in public sources.
References
- Royal Horticultural Society – Cosmos bipinnatus Sensation Series
- University of Illinois Extension – Cosmos care
- Veterinary Partner (VIN) – Safe and toxic garden plant images
Written by: Your Flowers Guide editorial team
We are a small independent group of flower lovers who research and review each guide using trusted horticultural and educational sources. Learn more about us