Pacific Cosmos Plant Care
Cosmos pacificus Melchert
Updated · Sources · How we source care data
Cosmos pacificus is a Mexican species of plants in the family Asteraceae. It is native to southwestern and west-central Mexico from Sinaloa to Chiapas.
Every 3–5 days
Full sun
50–80°F
40–60%
At a glance
How do you care for Pacific Cosmos?
Water Pacific 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 Pacific Cosmos Native To?
What Is the Pacific Cosmos?
Pacific Cosmos (Cosmos pacificus) belongs to the Asteraceae family within the Cosmos genus. Pacific Cosmos is native to southwestern and west-central Mexico from Sinaloa to Chiapas.
Pacific Cosmos displays an upright, bushy annual growth habit, reaching up to 2 ft tall with a spread of approximately 1.5 ft. Pacific Cosmos produces colorful daisy-like flowers in shades of pink, white, and purple.
Leaf size: approximately 3 inches.
How Often Should You Water a Pacific Cosmos?
Cosmos pacificus 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 Pacific Cosmos Need?
Pacific Cosmos thrives in full sun.
Light Requirement
Full sun
What Temperature and Humidity Does the Pacific Cosmos Prefer?
Cosmos pacificus grows best at temperatures of 50–80°F. Pacific Cosmos prefers humidity levels of 40–60%.
Temperature
50–80°F
Humidity
40–60%
What Soil Mix Works Best for a Pacific Cosmos?
Well-draining, fertile soil with a mix of compost and sand. Good drainage is essential for Pacific Cosmos to prevent waterlogging, which leads to root rot and fungal issues.
How Often Should You Fertilize a Pacific Cosmos?
Feed Pacific 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 Pacific 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 Pacific Cosmos?
Pacific Cosmos can be propagated through seeds. Similar propagation techniques also apply to chocolate cosmos plant care, which shares the same genus.
Is the Pacific Cosmos Toxic to Pets and Children?
Pet safety not verified
The ASPCA does not list Pacific 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 Pacific Cosmos?
Pacific 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 Pacific Cosmos Need?
Pacific Cosmos grows outdoors in USDA Zone 12a. It survives winters down to planting zone 12a. Pacific Cosmos is native to southwestern and west-central Mexico from Sinaloa to Chiapas. In cooler regions, grow Pacific Cosmos as a houseplant or bring it indoors before the first frost.
Hardiness Zone
Zone 12a
Keep exploring plants
Pacific 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.
Pacific 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 pacificus Melchert, family Asteraceae (first published in Phytologia 69(3): 213 (1990), nom. nov. (1990)) — World Flora Online record, IPNI name record.
- Pet toxicity: Pet safety not verified: the ASPCA does not list Pacific 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.
- Hardiness zone: USDA Zone 12a, calculated from the plant's minimum temperature.
- 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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