Dazzler Cosmos Plants

• Variety: Cosmos bipinnatus 'Dazzler'
• Common name: Cosmos / Cosmea / Mexican Aster
• Type: Half-hardy annual
• Flower form: Single
• Colour: Deep carmine-red, near blood-red when freshly opened
• Height: 90–150 cm (36–60 in)
• Flowering period: June–October
• Position: Full sun (minimum 6 hours)
• Soil: Well-drained, ordinary to poor fertility
• Spacing: 30 cm (12 in)
• Good for cutting: Yes – excellent
• Container suitable: Not ideal (very tall, wind-susceptible)
• Awards: All-America Selections winner
• Sold as: Jumbo plug seedlings, hand-sown by us
• Plant outdoors: After last frost (mid-May in most areas)
• Delivered: Late April to May by next-day courier. Collection from Castle Cary also available

Dazzler – The Darkest, Most Productive Cosmos We Grow

Dazzler may be the best of the dark-flowered cosmos. The colour is a deep, saturated carmine-red that reads as near blood-red when a bloom first opens, then settles into a rich, warm crimson as it matures. The petals have a slight blunt-tipped shape that distinguishes them from the pointed petals of most cosmos, and the flowers can reach 8 cm across. It is part of the Sensation series and an All-America Selections winner, which means it was trialled and selected by professional growers before it ever reached garden centres. At 90–150 cm, it is one of our tallest cosmos and needs support, but the height brings long stems that are exceptional for cutting.

When we were trialling our range, we planted a drift of 15 Dazzler and cut as many as we could every Friday. None were wasted and staff took them home. We always filled one Vileda bucket (which are quite large), and if the sun had been shining, we usually filled a second. That went on from late May until the end of October. Staggering quantities of flowers. Cosmos, incidentally, was used as a dye plant in Central America long before the Spanish arrived. The flower heads of the yellow-orange species produced textile dyes, and the tradition survived colonisation. Looking at a bucket of deep carmine Dazzler, you can see why.

Planting Companions for Cosmos Dazzler

Dazzler's dark, saturated colour needs a foil. Sensation Purity (clean white, same height) is the simplest and best contrast. The two planted in alternating groups give you a classic dark-and-light border that looks designed without being fussy. Apricotta offers a warmer pairing, the soft peach-pink against the deep crimson creating a colour-temperature contrast that works from midsummer through to autumn.

Behind a row of lavender like Hidcote or Grosso, Dazzler's carmine flowers against the silver-purple lavender foliage have a richness that stops people on the garden path. In a cutting garden, plant it in a dedicated row alongside the other tall cosmos and cut hard every week. The more you take, the more it gives. A dozen plants in a row, cut every Friday, will keep a household in cut flowers from midsummer to the end of October without breaking stride.

Why Buy Your Cosmos Seedlings from Ashridge?

No contract growing, no outside suppliers. Every cosmos plug is hand-sown and grown at our nursery in Somerset. We buy the best seed fresh each year because cosmos does not come true from saved seed. Your plants are grown on in our polytunnels and hardened off before dispatch. What arrives is a sturdy, garden-ready jumbo plug.

Next-day courier from late April. Our plant guarantee covers anything damaged in transit or that fails to establish. We are a small nursery and the people who answer the phone are the same ones who grew the plants.

Frequently Asked Questions

How tall does Cosmos Dazzler grow?

Dazzler reaches 90–150 cm (3–5 ft), making it one of the tallest cosmos. Support is not optional at this height. Put it in at planting time. Horizontal netting at 30–40 cm is the most effective method for a group planting. For full staking advice, see our cosmos growing guide.

Is Cosmos Dazzler good for cutting?

Dazzler is one of the most productive cut flowers you can grow. The long stems suit big vases and the flowers last 7–10 days in water. Cut in the morning, take the stem down to the first leaf joint, and strip the lower foliage. A row of 15 plants, cut weekly, will fill a large bucket every week from June to October.

What looks good planted with Cosmos Dazzler?

Dazzler's deep carmine pairs best with white or warm-toned companions. Sensation Purity (white) and Apricotta (soft peach) are the strongest options within the cosmos range. Outside the family, lavender provides a silver-purple base. Browse the full range in our cosmos collection.

Can I grow Cosmos Dazzler in a pot?

Not ideal. Dazzler is very tall, wind-susceptible, and needs serious support. In a very large, heavy, sheltered container it can be done, but it is not the first choice for a patio. For containers, look at the Sonata series or Xanthos, which stay compact and self-supporting. See our guide to growing cosmos in pots for the best container varieties.

Do I need to feed my cosmos?

In open ground, no. Cosmos actively flower better in poor, unimproved soil. Feeding produces foliage at the expense of blooms, and nitrogen-rich ground makes stems leggy and weak. If the plants look stressed, water first. In containers, nutrients leach from the compost, so feed fortnightly with half-strength tomato fertiliser once buds appear. This does make a noticeable difference to flower quality as the summer wears on, but only in pots. In the ground, leave them alone.