Sulphur cosmos (yellow cosmos) Cosmos sulphureus
Sulphur cosmos (yellow cosmos) (Cosmos sulphureus) is an annual flowering plant in the Asteraceae family, native to Mexico and Central America to northern South America. It grows 50 cm–1.5 m (20 in–4.9 ft) tall and 30–50 cm (12–20 in) wide, wants full sun and low water, and is hardy to about 0 °C (32 °F). Space plants about 35 cm (14 in) apart.
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Sulphur cosmos (yellow cosmos) at a glance
| Type | Annual flowering plant |
|---|---|
| Family | Asteraceae |
| Mature height | 50 cm–1.5 m (20 in–4.9 ft) |
| Mature spread | 30–50 cm (12–20 in) |
| Spacing | 35 cm (14 in) centre to centre |
| Sun | Full sun, at least 6 h of direct sun a day |
| Water | Low; drought tolerance moderate, waterlogging tolerance none |
| Soil pH | 6–7.5 |
| Cold hardiness | About 0 °C (32 °F) once established (roughly USDA zone 10) |
| Heat stress | Likely above about 40 °C (104 °F) |
| Flowering | about 7–11 weeks after planting, for 10–17 weeks |
| Days to maturity | About 100 days from planting |
| Wind tolerance | Low |
| Pollinator value | High |
| Edible | Not grown as food |
| Native to | Mexico and Central America to northern South America |
| Common in gardens of | 🇲🇽 Mexico, 🇧🇷 Brazil, 🇨🇴 Colombia, 🇺🇸 United States, 🇹🇭 Thailand, 🇻🇳 Vietnam, 🇮🇩 Indonesia, 🇵🇭 Philippines, 🇮🇳 India, 🇯🇵 Japan, 🇰🇷 South Korea, 🇬🇧 United Kingdom |
Is Sulphur cosmos (yellow cosmos) toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
Not known to be poisonous.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Sulphur cosmos (yellow cosmos)
No well-documented helpful pairing. Group it with plants that like full sun and low water.
Questions about Sulphur cosmos (yellow cosmos)
- How far apart should I plant Sulphur cosmos (yellow cosmos)?
- About 35 cm (14 in) apart, centre to centre. A mature plant spreads 30–50 cm (12–20 in).
- Does Sulphur cosmos (yellow cosmos) need full sun?
- Full sun: at least 6 hours of direct sun a day.
- How much water does Sulphur cosmos (yellow cosmos) need?
- Low water. Drought tolerance is moderate and waterlogging tolerance none.
- How cold-hardy is Sulphur cosmos (yellow cosmos)?
- It tolerates about 0 °C (32 °F) once established, roughly USDA zone 10. As an annual it is usually planted out after the last frost.
- When does Sulphur cosmos (yellow cosmos) flower?
- About 7–11 weeks after planting, for 10–17 weeks.
- Is Sulphur cosmos (yellow cosmos) poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. Not known to be poisonous.
- What grows well with Sulphur cosmos (yellow cosmos)?
- There is no well-documented companion pairing for Sulphur cosmos (yellow cosmos). Group it with plants that like the same sun (full sun) and water (low).
Sources and evidence
Evidence grade A (A: strong evidence).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- RHS Find a Plant (plant profiles and growing guides), Royal Horticultural Society
- CABI Invasive Species Compendium, CABI
Notes and assumptions
- A half-hardy annual in cool climates: sow under glass in spring and plant out after the last frost.
- A cutting-patch flower: picking the stems often keeps new ones coming.
- Yellow, orange or red daisies that thrive in poor soil and heat; a common roadside and temple flower in the tropics, where it has widely naturalised. Dye gardeners use the petals for orange.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Lettuce Lactuca sativa
- Sunflower Helianthus annuus
- French marigold Tagetes patula
- Zinnia Zinnia elegans
- Cosmos Cosmos bipinnatus
- Purple coneflower Echinacea purpurea
- Black-eyed Susan Rudbeckia hirta
- French tarragon Artemisia dracunculus