The cheapest way to cultivate these much-loved flowers
Whether you’re an experienced gardener or not, here’s how to grow Cosmos, one of the best-loved annuals, from seed. It’s easy to see why Cosmos are so popular. Breakthroughs in breeding have led to new varieties such as Cupcakes and Lemonade. However, it is also down to great garden performance, according to Thompson & Morgan. Read about another unusual Cosmos.
Born out of a chance find in a California back yard in 2007, gardener Diane Engdahl discovered an unusual Cosmos. She sent the seed to the seedsmen. Instead of its flower being made up of individual petals, they were fused, creating one single ‘cup’.
For nearly 10 years, plant breeders have been ‘fixing’ this new trait across the colour range, developing new shades and refining the shape. During the Year of the Cosmos, visitors to RHS Garden Wisley named their favourite variety as part of the RHS’s People’s Choice Competition. Cosmos bipannatus Cupcakes White came out on top of the 84 varieties on show.
Cosmos Lemonade
Also from Thompson & Morgan is Lemonade, a multi-flowering, subtle yellow Cosmos with a striking white eye. T&M’s plant breeding team took a very bright yellow, but late-flowering Japanese variety and crossed it with earlier-flowering Cosmos with better, shorter habits. The resulting delicate, yellow blossoms are loved by all.
Flowers are produced throughout the summer on short to medium-high, branching plants, great for patio pots or as a border filler. Cosmos Lemonade also makes a good cut flower and looks stunning in a vase.
How to grow Cosmos from seed
- Sow seeds in a heated greenhouse or propagator in April.
- Good light is important to prevent leggy seedlings.
- 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, 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.
For further information on growing Cosmos, go to www.thompson-morgan.com/cosmos-article to read an article by Graham Rice taken from The Seed Raising Journal, or visit the half-hardy annuals from seed page. Read more about half-hardy annuals for beginners.
