Burpee 'Sensation Mix' Cosmos Seeds
The easiest cut flower in the garden. Direct-sow after frost, ignore completely, cut armloads from July through frost. 'Sensation' hits 4 feet with dinner-plate-sized blooms in pink, rose, and white.

Asteraceae
Cosmos bipinnatus
Feathery foliage and wide-open blooms for the most hands-off gardener
Ermell via Wikimedia Commons (cc by_sa_4)
About this plant
Cosmos bipinnatus is a member of the Asteraceae family, the same vast clan that includes daisies and sunflowers, and it carries that family's signature look: broad, open flower heads that face the sky like small satellite dishes. The genus name, Cosmos, comes from the Greek word for order or harmony, a nod to the perfectly arranged petals that ring each bloom. As a perennial, it returns season after season, putting down roots and coming back without asking much of you in return.
What makes this plant a genuine beginner's ally is its rated difficulty: beginner. It grows outdoors and demands only around ten minutes of attention per week. Its USDA hardiness range spans Zones 1a through 13b, which covers virtually every corner of the continental United States, Alaska, Hawaii, and the territories, meaning almost no gardener in America needs to worry about whether their climate is too harsh or too mild. Medium water needs means it sits comfortably between drought-stressed and waterlogged: not a cactus, not a bog plant, just a sensible, adaptable grower that rewards consistency over fuss.

Bloom
Friedrich Haag via Wikimedia Commons (cc by_sa_4)

Gallery
Joydeep via Wikimedia Commons (cc by_sa_3)

Gallery
Joydeep via Wikimedia Commons (cc by_sa_3)
Step by step
Find a spot with enough light for its needs. Plant it outdoors, ideally sheltered from the harshest afternoon wind.
Any good all-purpose potting mix or well-drained garden soil will do. Give each plant enough room for its mature spread. Crowding causes more problems than undersizing the bed. Water it in gently once it's settled.
Water when the top inch of soil feels dry, roughly once a week in summer. Soak the soil, then let it breathe before the next round.
This one is very forgiving. A balanced all-purpose fertiliser at the start of the growing season is plenty, and you can skip a month without harm. Plan on 10 minutes a week of hands-on care: watering, a quick trim, checking for pests.
Expect flowers in June to October. Deadhead spent blooms to encourage more, and take a minute to notice them. This is why you planted it.
Year at a glance
Approximate for a temperate North American zone. Shift earlier the further south you garden, later the further north.
Jan
January: Rest
Dormant
Feb
February: Rest
Dormant
Mar
March: Wake up
New growth
Apr
April: Tend
Routine care
May
May: Tend
Routine care
Jun
June: Bloom
Flowers expected
Jul
July: Bloom
Flowers expected
Aug
August: Bloom
Flowers expected
Sep
September: Bloom
Flowers expected
Oct
October: Bloom
Flowers expected
Nov
November: Wind down
Prep for dormancy
Dec
December: Rest
Dormant
Recommended supplies
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Pet & people safety
Verified against a primary poison-control source. Still, no plant is a snack. Grazing in quantity can upset the stomach of any animal, and the hotline below is there if something goes wrong.
Dogs
Non-toxic
Non-toxic per ASPCA.
Source: ASPCA
Record covers Garden Cosmos toxicity for Dogs.
Cats
Non-toxic
Non-toxic per ASPCA.
Source: ASPCA
Record covers Garden Cosmos toxicity for Cats.
Bloomwise is not a substitute for veterinary or medical advice. Every line above comes from a hand-verified reference.
Frequently asked
Garden Cosmos is hardy in USDA zones 2a to 11b. If your winter lows fall outside that range, grow it in a container you can bring indoors, or treat it as an annual.
Water about once a week in summer, adjusting for rainfall. Soak the soil, then let it breathe before watering again.
Garden Cosmos prefers four to six hours of sun, ideally morning light.
Yes. Garden Cosmos is listed as non-toxic to dogs and cats by verified poison-control sources. No plant is a snack, though, and grazing in quantity can still upset any animal's stomach.
Yes, this is a forgiving plant that tolerates inconsistent watering and the occasional missed feeding. A good choice for a first garden.
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Sources
Plant facts on this page come from a blend of public-domain and open-licensed datasets: Biodiversity Heritage Library (historical botanical illustrations, public domain), USDA PLANTS (taxonomy, public domain), GBIF (occurrence and taxonomy, CC-BY 4.0), OpenFarm (crop guides, CC-BY-SA 3.0), and Open-Meteo (climate and hardiness lookup, CC-BY 4.0). Toxicity records come from the ASPCA Animal Poison Control Center and the Pet Poison Helpline; every row is hand-verified against a primary reference.