Cosmos
Cosmos bipinnatus
Family Asteraceae
Cosmos may be the highest-return seed packet in the rack: scattered on bare dirt and ignored, it becomes an airy two-to-five-foot cloud of daisies that yields armloads of cut flowers until frost. Poor soil actually improves the show — neglect is the recipe.
Bees work the open blooms all summer and fall, making it the easy backbone of a pollinator strip or a first garden. It asks for sun and absolutely nothing else. Shake out a packet where you want flowers and get out of the way.
Full Sun
Low water
Very Fast growth
Attracts bees
None winter chill
From the print shop
Growing cosmos? Hang it.
Our Plant Library collection carries cosmos — Cosmos bipinnatus, print Nº 131, “Cosmos.”
526 designsfrom $12.99white or black backgroundmatte poster, unframed
Will it fruit where you are?
Enter your ZIP — we look up your USDA hardiness zone (2023 map) and check it against what cosmos actually needs.
Life cycleAnnualCosmos · Common problems
Common cosmos problems
Pests
1 problem on file
- Aphids (rare)
Diseases
1 problem on file
- Powdery Mildew late
Cosmos · Growing & propagation
Growing cosmos
- Light
- Full Sun
- Water
- Low
Rich living makes floppy plants
Soil- POOR soil is better
Sharp drainage · pH 6.0 - 8.0
Fertilizer- NONE
Feeding cosmos is sabotage
Pruning- None
Deadhead to the next side bud; cut deep for the vase and it branches harder. Stake tall types or let them lean on friends.
Spacing- 12 in
How to plant & propagate cosmos
Maturity- 70-90 days
From seed- Direct-sow on lean soil after frost
- Propagate
- From seed
Cosmos · Calculators & field guides
A little help in the garden.
Cosmos · Yearly calendar
The cosmos year, month by month
Jan
No calendar activity is listed for this month.
BloomBloomJune
What each band means
- Bloom — flowers open — pollinators working, frost on blossoms is the danger.
These are the species' typical months — expect them a few weeks earlier in warm zones and later in cold ones. Watch the plant, not just the calendar.
Cosmos · Ecology & uses
Ecology & uses
Cosmos bipinnatus
Cosmos in the garden system
- Herbaceous layer annual
- Nectary/insectary
Attracts- Bees
Moisture- Upland / dry
Deer- Browsed
Protect young plants
Origin- Introduced
What cosmos is grown for
✓ Commonly eaten
Use- Cut flowers
- Use
- Pollinator strips
- Use
- First gardens
Edibility, identification, and traditional-use notes here are general reference — not medical or veterinary advice, and not a claim that any plant treats or prevents anything. Medicinal ratings record how strongly a plant features in herbal tradition, nothing more. Never eat or dose a plant you have not positively identified. More on how to use this library.
Cosmos · Varieties & cultivars
Choosing a cosmos variety
'Sensation' (classic 4 ft); 'Sonata' (knee-high); 'Double Click' (ruffled); 'Apricot Lemonade'
Sources & plant identity
Know what you’re growing.
See where the knowledge comes from.
Cosmos
Cosmos bipinnatus
The plant, at a glance.
- Botanical name
- Cosmos bipinnatus
- Plant family
- Asteraceae
- Growth habit
- Annual
- Origin
- Introduced
- USDA plant symbol
- COBI2
- Invasive risk
- Low
Hardiness, size and timing vary with your cultivar, soil and climate.
Rooted in research.
University extension research, brought together with hands-on growing experience at Story Thyme Farms.
Questions
Cosmos questions, answered straight.
Is cosmos safe for kids and pets?
Cosmos is commonly eaten and isn't considered toxic, but "commonly eaten" isn't a guarantee for any particular person or animal — allergies, quantity, and which part you eat all matter. Never eat a plant you haven't positively identified, and check with a vet before letting pets or livestock graze anything new.
How do you propagate cosmos?
From seed.
Elsewhere
Where cosmos sits in the library.
Sunflower
Zinnia
Peony
Daylily