Photo: © Daniel IseliPlantoScanImage: PlantoScan
Cosmos Plant Care
Cosmos bipinnatus Cav.
Updated · Sources · How we source care data
With delicate, fern-like foliage and vibrant pink, white, or purple daisy-like flowers, this plant originates from Mexico. Plant collectors are drawn to this species for its long-lasting blooms and ability to attract pollinators like bees and butterflies to the garden.
Every 3–5 days
Full sun
50–80°F
40–60%
At a glance
How do you care for Cosmos?
Water Cosmos every 3–5 days, letting the top layer of soil dry out between waterings, and give it full sun. It prefers temperatures of 50–80°F (10–27°C) and 40–60% humidity. Fertilize it every 4 months during the growing season.
Where Is the Cosmos Native To?
What Is the Cosmos?
Cosmos (Cosmos bipinnatus) belongs to the Asteraceae family within the Cosmos genus. Cosmos is native to the Americas. Cosmos is also known as Garden Cosmos, Common Cosmos, Mexican Aster.
Cosmos displays an upright, bushy annual growth habit, reaching up to 2 ft tall with a spread of approximately 1.5 ft. Cosmos produces colorful daisy-like flowers in shades of pink, white, and purple.
Leaf size: approximately 3 inches.
How Often Should You Water a Cosmos?
Cosmos bipinnatus requires watering every 3–5 days. Allow the top layer of soil to dry between waterings to prevent root rot. Reduce watering frequency during winter when growth slows.
Watering Frequency
Every 3–5 days
Let soil partially dry between waterings
What Light Does the Cosmos Need?
Cosmos thrives in full sun.
Light Requirement
Full sun
What Temperature and Humidity Does the Cosmos Prefer?
Cosmos bipinnatus grows best at temperatures of 50–80°F. Cosmos prefers humidity levels of 40–60%.
Temperature
50–80°F
Humidity
40–60%
What Soil Mix Works Best for a Cosmos?
Well-draining, fertile soil with a mix of compost and sand. Good drainage is essential for Cosmos to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Cosmos?
Feed Cosmos every 4 months during the growing season (spring and summer) with a balanced fertilizer diluted to the strength on the label.
Pause feeding in autumn and winter, when growth slows, and never fertilize dry soil — water first.
Fertilizing
Every 4 months
During the growing season
The PlantoScan app can remind you when to water and when to fertilize each plant.
How Do You Repot a Cosmos?
Not applicable as an annual plant. Choose a pot one size larger than the current container, and ensure it has drainage holes to allow excess water to escape.
How Do You Propagate a Cosmos?
Cosmos can be propagated through seeds. Similar propagation techniques also apply to chocolate cosmos plant care, which shares the same genus.
Is the Cosmos Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Cosmos, so we can't confirm whether it is safe for cats and dogs. Keep pets from chewing it as a precaution.
This is a general caution, not veterinary or medical advice. If your pet ate a plant, contact your vet or animal poison control.
See all plants toxic to cats and plants toxic to dogs.
What Pests and Diseases Affect the Cosmos?
Cosmos is susceptible to aphids, spider mites, whiteflies. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.
Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.
What USDA Hardiness Zone Does the Cosmos Need?
Cosmos grows outdoors in USDA Zone 10b – 13b. It survives winters down to planting zone 10b. Cosmos is native to the Americas. In cooler regions, grow Cosmos as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 10b – 13b
Keep exploring plants
Cosmos is one of many species covered in the complete plant care and identification guide, which groups plants by genus, attribute, and popularity.
It belongs to the Cosmos genus — compare its care with other Cosmos species on PlantoScan.
Cosmos is part of the Asteraceae plant family — browse all Asteraceae genera and species.
Cosmos thrives in bright light and direct sun — see other bright-light plants.
More Cosmos Species
Other Cosmos species in PlantoScan's care catalogue share similar watering, light, and soil preferences:
Sources
- Scientific name & taxonomy: Cosmos bipinnatus Cav., family Asteraceae (first published in Icones et Descriptiones Plantarum 1 1791) — World Flora Online record, IPNI name record, Wikidata.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Cosmos, so we can't confirm whether it is safe for cats and dogs. Checked against the ASPCA plant list; any other toxicity note on this page comes from PlantoScan's plant database.
- Photo: © Daniel Iseli, PlantoScan.
- Hardiness zone: USDA Zone 10b – 13b, estimated from the plant's typical growing conditions.
- Care values(watering, light, temperature, humidity, soil, fertilizing): PlantoScan's plant database, filtered by automatic plausibility checks — values that fail them are hidden. How we source and check plant data.
Spotted a mistake? Email info@upvision.media with the page link — we check and correct reported errors.
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