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Photo: Joydeep / CC BY-SA 3.0 / Wikimedia Commons
FlowerExotic

Cosmos

Cosmos bipinnatus

A feathery-leaved annual with wide, simple daisies, sown from seed between October and December; it flowers from midwinter to April and asks very little once up.

Mature size0.6–1.5 m tall, 0.3–0.6 m spreadGrowthFastSunFull sunWaterLow
Heat: 3 of 5
Salt: 2 of 5
Drought: 4 of 5
Shade: 1 of 5
Ease of care: 4 of 5
Use in a designGet it looked after

Season

Through the Dubai year

How Cosmos behaves through Dubai's seasons, month by month.

J
F
M
A
M
J
J
A
S
O
N
D
24°
26°
29°
34°
38°
40°
42°
42°
40°
36°
31°
27°

Sow seed where it will flower

Oct – Dec

Flowers from midwinter to spring

Jan – Apr

Deadhead and stake

Jan – Mar

Declines in the heat

May – Aug

  • Sow seed where it will flower: Oct–Dec

    Press seed into loose soil, barely covered, and keep moist until it germinates in 1–3 weeks.

  • Flowers from midwinter to spring: Dec–Apr

    Deadhead regularly to prolong the display.

  • Deadhead and stake: Jan–Mar

    Cut spent flowers to a side bud; support tall stems with twiggy canes.

  • Declines in the heat: May–Aug

    Plants are cleared in April–May; summer sowings struggle.

Cosmos has a short, easy Dubai season. Sow seed from October to December, directly where it will grow, pressing it into loose soil and keeping it moist until seedlings are up in one to three weeks. Plants grow quickly through November and December, and flowers open from about December, peaking from January to March when highs are 24–29 °C. Deadhead through winter to keep it flowering. By April, as highs reach 33 °C, flowering slows, and by May plants are tired and are cleared for summer bedding such as Vinca and Portulaca.

Meet the plant

Meet the Cosmos

Meet cosmos, the annual that makes a bed look as though it was sown by the wind. Feathery, thread-fine foliage forms a soft green haze, and above it single daisies in white, pink and crimson float on stems so slender that they seem to hover and nod at every passing breath of air.

That lightness is technical as much as pretty. The finely divided leaves let light and air pass through, so a bed of cosmos never reads as a solid block, and a stand 1.5 m tall still lets you see the wall behind. It is the opposite of a clipped, heavy hedge, and the contrast is the point.

In Dubai it belongs to the cool months, sown from seed in October and gone by April. The mood is relaxed and cottage-like, informal and generous: a plant for a cutting patch or the soft back layer of a border, not a formal edge. It asks for sun, lean soil and little water, and gives its flowers freely.

Cosmos bipinnatus is a Mexican annual with finely cut, almost thread-like leaves, which is what 'bipinnate' means: leaves divided twice. They hold single, wide-open daisies in white, pink, magenta and crimson on tall, wiry stems. The result is a plant that moves in a breeze and lets light through, so a stand of cosmos stays airy even at 1.5 m. The RHS describes it as a bushy annual that can reach 2.5 m, with flowers up to 8 cm across and a yellow central disc.

In Dubai, seed sown in place from October to December flowers in roughly two months and carries on to about April. NC State rates cosmos as heat and drought tolerant once established, and the RHS notes that plants will not flower in shade. The hot months end its season: plants left past April decline in the heat, and tall plants from late sowings grow leggy before they flower. Cosmos sulphureus, the orange 'yellow cosmos', is usually described as better in heat and humidity if you want to push the season.

Cosmos is a low-input plant, and the common mistake is to over-care for it. Rich soil and generous feeding give tall, leafy plants with few flowers; too much water makes them flop. A lean, free-draining bed in full sun, a few twiggy supports for tall types and regular deadheading keep it flowering, as the RHS advises. Leave a few seedheads to ripen at the end of the season if you want volunteers: NC State notes the plants readily reseed, and the seedlings will appear in the next cool season.

Design

Where to use it

Cottage-style winter beddingCut flowerSelf-seeding fillerPollinator planting

Sow cosmos in full sun in a lean, free-draining bed rather than your richest soil, and use it in the soft, back-of-border layer or in a cutting patch where its height is welcome. It suits informal planting; in a formal scheme use it behind lower bedding, with a few bamboo canes or twiggy supports for the tallest types. Sow in drifts, thin to 30–45 cm and let the stems intermingle. Because it is gone by May, plan the following summer bedding in the same bed.

The flower in bloom of a Tagetes erecta found in Innis Woods Metro Park.

Marigold

Marigold's compact orange and gold pompoms sit well in front of cosmos's airy stems, with the same October timing and similar water needs.

Close-up of a zinnia flower (Zinnia elegans) Stacked with Helicon Focus from 15 pictures, taken in a garden in Bamber...

Zinnia

Zinnia is another cut-flower annual from Dubai Municipality's bedding list, giving a denser, bolder bloom to contrast with cosmos's lightness.

Antirrhinum majus BCBG (02)

Snapdragon

Snapdragon's upright, formal spikes give structure among cosmos's looser, wiry stems in a mixed cool-season border.

Flower beds in park Kolomenskoye (Moscow). Helianthus annuus ‘Teddy Bear’

Sunflower

Sunflower provides the tall, bold back layer, with cosmos filling the middle in the same October sowing window.

Care guide

How to grow it in Dubai

Watering

Summer: Not grown outdoors through summer; it is a cool-season annual in Dubai.

Winter: Once established, water deeply once or twice a week by drip; excess water gives soft, floppy growth and fewer flowers.

Establishment: Keep the seedbed moist for 5–10 days after sowing, then water deeply every few days until seedlings are 15 cm tall.

Soil
Moderately fertile, free-draining soil in full sun; avoid both heavy, wet ground and very rich ground, which gives leaf instead of flower.
Feeding
Little or none beyond compost at sowing; a single balanced feed at around six weeks if growth looks pale.
Pruning
Pinch the tip of young plants once to encourage branching; deadhead to prolong flowering; stake tall types.
Planting
Sow seed directly from October to December, barely covered, 30–45 cm apart; it germinates in one to three weeks. Nursery seedlings can be planted out from October.
Pests
AphidsPowdery mildew in humid spellsStem rot in wet soil

Avoid these

Common mistakes

  • Planting it in rich, heavily fed soil. It produces tall, leafy plants with few flowers and flops; cosmos does best on lean ground.
  • Overwatering. Established cosmos is drought tolerant, and wet soil gives soft, floppy growth that needs staking.
  • Sowing too deep. Seed should be barely covered; deep sowing slows or prevents germination.
  • Sowing late in the season and expecting a long display. Seed sown after December has little time before the heat arrives in April.
  • Leaving it too long once flowering stops. A tired, seed-heavy bed looks untidy; clear it and replant for summer.

Extra notes

Good to know

  • The RHS describes Cosmos bipinnatus as a tall, bushy annual that can reach 2.5 m; garden cultivars are usually shorter, and dwarf series are available.
  • NC State rates it as heat and drought tolerant once established and notes that it readily reseeds, which is why deadheading is optional.
  • Cosmos sulphureus, the orange or yellow cosmos, is generally described as better in heat and humidity, and is the species to try if you want to push the season.
  • It is a useful pollinator plant: NC State notes that it attracts bees, butterflies and birds.

Toxicity: Not known to be significantly toxic to people or pets.

Pros

  • Airy, long-flowering colour from midwinter to April for very little effort
  • Easy and cheap from seed sown straight into the bed
  • Tolerates poor, dry soil once established
  • Reseeds if allowed, and makes a good cut flower
  • Attracts pollinators, including bees and butterflies

Cons

  • Finishes with the heat in April–May and cannot be kept through summer
  • Tall types flop in rich soil or wind and need staking
  • Aphids and powdery mildew can appear in humid spells
  • Looks untidy once flowering slows, so clear it promptly

FAQ

Common questions

When should I sow cosmos in Dubai?
From October to December, directly where it will flower. Seed germinates in one to three weeks, and flowers open from around December.
Can cosmos grow in a Dubai summer?
Not reliably. It is drought and heat tolerant once established, but Dubai's cool-season sowing gives the best results, and the display ends in April–May. Cosmos sulphureus is the species to try for warmer weather.
Why is my cosmos tall and floppy with few flowers?
Usually rich soil, too much feeding or too much water. Cosmos does best on lean, free-draining ground with little water once established.
Does cosmos come back by itself?
It reseeds readily, according to NC State, so leaving a few seedheads at the end of the season gives volunteer seedlings in the next cool season.
Is cosmos good for cutting?
Yes. The RHS notes that it provides flowers for cutting over a period of months, and cutting regularly also keeps the plant flowering.

Not sure how it suits your garden?

Ask about Cosmos on WhatsApp

Sources

  1. 1. RHS: Cosmos bipinnatus
  2. 2. NC State Extension Gardener Plant Toolbox: Cosmos bipinnatus
  3. 3. Kew Plants of the World Online: Cosmos bipinnatus
  4. 4. Acacia Garden Center: Dubai Garden Calendar

Last reviewed 2026-10-05 by Ghaf Gardens horticulture desk.

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