Thompson & Morgan has been at the forefront of cosmos breeding for 10 years since some unusual seeds arrived from California.

The ‘Cupcakes’ series of the ever-popular cosmos was born out of a chance find in a California back yard in 2007. When Diane Engdahl discovered an unusual cosmos flower in her garden in Santa Rosa, she sent the ensuing seed to the plant breeding team at Thompson & Morgan. Instead of its flower being made up of individual petals, rather like a daisy, as with most cosmos, the petals of this unique bloom were fused together, creating one single ‘cup’.

For nearly 10 years, plant breeders at Thompson & Morgan have been busy ‘fixing’ this new trait across the cosmos colour mix, developing new shades and refining the habit of this new cosmos shape. This long-standing cottage garden favourite was celebrated in 2016’s Year of the Cosmos and visitors to RHS Garden Wisley were asked to vote in a poll to name their favourite garden cosmos as part of the Royal Horticultural Society’s annual People’s Choice Competition. Once votes were gathered, Cosmos bipannatus ‘Cupcakes White’ came out on top of the 84 varieties on show in the RHS garden. Read more about the RHS People’s Choice Competition at

Cosmos 'Cupcakes White' part of our Cosmos 'Cupcakes' seed range

It’s easy to see why cosmos are so popular. Sales of cosmos seed and plants have increased hugely over the past 10 years. This is partly due to breakthroughs in breeding which have led to new varieties such as ‘Cupcakes’ and ‘Lemonade’ (see below), but it is also down to the fabulous garden performance of this very stylish flower. Available in so many colour ways, heights and flower types; easy to grow; not prone to disease or pest attacks – cosmos really are every gardener’s dream plant!

Initially marketed as part of Thompson & Morgan’s exclusive Cosmos ‘Cupcakes’ mix, ‘Cupcakes White’ boasts pristine white petals which are fused together to form the single ‘cup’ that is the unique trademark of the ‘Cupcakes’ series. Tall, bushy plants are free flowering; ideal for elegant border designs and container growing, and perform well in all types of weather. Cosmos make fabulous cut flowers and each plant will produce an impressive number of blooms.

During T&M’s trials, it was remarked that bees appeared to be taking shelter from wind and rain inside the flower ‘cups’, with sometimes more than one bee sharing the protection that the fused petals afford. Cosmos are always a favourite with pollinating insects, but the knowledge that bees are using this new variety to take refuge from inclement weather, makes them all the more appealing.

Top tips for growing cosmos from seed
• Sow cosmos seeds in a heated greenhouse or propagator in April.
• Good light is important to prevent ‘stretching’
• Young plants can be planted out after the very last frosts, usually in late May/early June
• Regular dead-heading will promote flowering right up to the first frosts
• When dead-heading cosmos, cut the stem right back to the first leaf rather than just pulling the flower head off
• Seed can be planted outside, where you’d like them to flower, in May or early June

Thompson & Morgan also offers a number of cosmos varieties as plants which, depending on the size of the plant at the time of delivery, can be planted straight out into the garden, or they can be potted up and grown on before transplanting.

Cosmos ‘Cupcakes White’ – 1 packet (30 seeds) £1.99
Cosmos ‘Cupcakes Mixed’ – 1 packet (100 seeds) £1.99
Height: 120cm (48″). Spread: 60cm (24″)

Also from Thompson & Morgan’s own breeding comes another stunning cosmos variety – ‘Lemonade’

cosmos lemonadeTo create this multi-flowering subtle yellow cosmos with a striking central white eye, T&M’s plant breeding team took a very bright yellow, but late-flowering Japanese cosmos variety and crossed it with earlier-flowering cosmos with better, shorter habits. The resulting delicate, yellow blossoms of Cosmos ‘Lemonade’ marked a major breakthrough in cosmos breeding. Flowers are produced en masse throughout the summer on short to medium-high, branching cosmos plants. Fantastic for patio pots or as a robust and floriferous border filler – its colouring and habit means that it combines well with most other plants in bedding or container displays. Cosmos ‘Lemonade’ also makes a great cut flower and looks stunning in a vase, either on its own or mixed in with other flowers.

Cosmos ‘Lemonade’ – 1 packet (30 seeds) £2.49
Cosmos ‘Lemonade’ – 30 garden-ready plants £14.99
Height: 60cm (24in). Spread: 40cm (16in)

For further information on growing cosmos, please go to Thompson & Morgan’s website and read an article by Graham Rice taken from The Seed Raising Journal from Thompson & Morgan.

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