Cosmos
Cosmos bipinnatus 'Sensation'
flowerCosmos is an airy, fast-growing annual with feathery foliage and a long summer-to-frost show of daisy-like blooms in pink, white, and magenta on tall, graceful stems. It thrives on neglect, flowering best in poor soil, and is a powerful magnet for bees, butterflies, and beneficial insects, making it as useful in the vegetable garden as it is pretty in the border or vase.
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Sun
full sun
💧
Water
Every 3 days
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Bloom
~75 days
📊
Difficulty
easy
🌱
Lifecycle
annual
One season, then done
↔️
Spacing
12-18 in. apart
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Planting Depth
1/4 in.
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Soil pH
6.0-7.0
Growing Details
Soil Type
Average, well-draining
Hardiness Zones
Zones 3 – 11
Grown as an annual — this range is its winter hardiness, but you can grow it for a single season in any zone.
When to Fertilize
Usually none; rich soil reduces blooms
Fertilizer
None to minimal; avoid nitrogen
🌱 Growing Guide
Direct sow after the last frost in full sun and lean soil, since rich, fertile ground produces lush foliage at the expense of flowers, and cosmos is drought-tolerant once established. Deadhead spent blooms regularly to keep the plant flowering instead of setting seed, stake the tall Sensation types, which can topple, and let a few late flowers go to seed and cosmos will often self-sow.
🌼 Have a different variety?Cultivars of the same species usually share the same basic care — they differ mainly in flower color, height, and bloom form, not in how you grow them. So this guide still applies even if your exact variety isn't the one shown.
Planting Calendar
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Direct sow
Apr 29
🌸
Projected first bloom
Jul 13
JJan
FFeb
MMar
AApr
MMay
JJun
JJul
AAug
SSep
OOct
NNov
DDec
✅ Plant alongside
Good neighbors that attract beneficial insects or deter pests
- Tomatoes — Draws pollinators and parasitic wasps that hunt hornworms
- Squash — Attracts bees that improve fruit set
- Brassicas — Lures hoverflies and wasps that prey on aphids and caterpillars
- Beans — Adds nectar that supports beneficial insects
🛡️ Pest & disease prevention
Proactive ways to stop trouble before it starts — tap a name with an arrow for its full guide
Cosmos itself attracts ladybugs and lacewings that clear aphids; rinse heavy colonies
Space for airflow and water at the base, not overhead
Control leafhoppers and remove any stunted, yellowed plants promptly
🌸 Blooms & cutting
Cut stems for the vase when the buds are just opening, in the cool of the morning, which encourages more bloom. Frequent cutting and deadheading keep the plant flowering right up to frost; leave some final flowers to dry on the plant if you want to save seed.
🥗 Nutrition & benefits
Cosmos is grown for beauty rather than eating, but it earns its place as a top nectar source that feeds bees, butterflies, and hoverflies and boosts pollination of nearby food crops.
For educational and informational purposes only — HomeSown is not medical, health, or other professional advice. Always positively identify any plant before handling or eating it; some plants, and some parts of otherwise-edible plants, are toxic. Consult a qualified professional before consuming or otherwise using any plant, especially if you are pregnant, nursing, taking medication, or have a health condition.