4 named cultivars

annualN. America Native

Sulphur Cosmos

Cosmos sulphureus

Same species

4 named cultivars

Essentials

At a Glance

Plant Type

Annual

Height

24 inches

Width

18 inches

Light

Full Sun, Partial Sun

Water

Low to moderate

Humidity

Average

Lifespan

Annual

Native To

Mexico, Central America

Toxicity

Non-toxic

The Story

Plant Bio

Cosmos sulphureus, commonly known as yellow cosmos, is a fast-growing annual flower that produces bright yellow daisy-like blooms. This species is known for its tolerance to poor soils and drought conditions, and it attracts pollinators such as butterflies and hummingbirds.

Uses & Benefits:

Cosmos sulphureus adds vibrant color to garden borders and attracts pollinators, enhancing garden biodiversity.

Its drought tolerance makes it ideal for water-conserving landscapes.

Provides nectar for butterflies and hummingbirds, supporting local ecosystems.

Planting

How to Grow

Tuck seeds into well-draining soil in early spring for best germination.
Water regularly to keep soil moist but not waterlogged during seedling stage.
Thin seedlings to promote airflow and prevent overcrowding after emergence.
Stake taller varieties to support growth and prevent wind damage.
Fertilize monthly with a balanced, water-soluble fertilizer during the growing season.
Deadhead spent flowers to encourage continuous blooming and maintain plant health.

Pro Tip

Sow cosmos in full sun for vibrant blooms and strong growth.

Keep It Thriving

Care Guide

Do

Water deeply once a week during dry spells 🌱
Pinch back early growth to encourage bushier plants
Remove dead or diseased foliage to prevent pests

Don't

Avoid overwatering to prevent root rot ❌
Don’t overcrowd plants to ensure good air circulation
Refrain from fertilizing late in the season to prevent legginess

Seasonal Care Calendar

Task	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Deadhead
Harvest
Plant

Watch Out For

Pests & Diseases

Common Pests

Common Diseases

In the Garden

Landscape Uses & Companions

Landscape Uses

Vibrant flower bordersWildflower meadowsButterfly-friendly gardens

Companion Plants

Marigolds Zinnias Sunflowers Cosmos bipinnatus Lavender

Multiply

Propagation Methods

Good to Know

Common Questions

Sulphur Cosmos questions

What zones can Sulphur Cosmos grow in?

Sulphur Cosmos is hardy in USDA Zone 10. Inside that range it survives winter in the ground; outside it, grow it as an annual or a container plant you protect.

Is Sulphur Cosmos deer resistant?

Yes — Sulphur Cosmos is rated deer-resistant. Deer typically pass it over, though extreme hunger can override any plant's defenses.

When does Sulphur Cosmos bloom?

Sulphur Cosmos typically blooms in mid-summer through late summer. Exact timing shifts a week or two with your zone — Sow's bloom calendar maps it to your garden.

Does Sulphur Cosmos need full sun?

Sulphur Cosmos does best in full sun to part shade. In hot climates, afternoon shade keeps blooms fresher longer.

Is Sulphur Cosmos drought tolerant?

Yes — once established (usually after the first full season), Sulphur Cosmos handles dry spells with minimal watering. Water deeply its first year to build the root system that makes that possible.