The best cosmos to grow

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A shorter newcomer cosmos whose single flowers fade from rich red to paler ‘antique’ tones and finally  to a rather watery shade. Deadhead when the flowers begin to look ragged. Height 60cm.

Wonderful, glowing-orange single cosmos flowers on plants with appealingly open growth, slow to start but prolific later. Lovely interplanted among dark-leaved cannas or dahlias for contrast in habit and colour. Height 1m.

Double-flowered cosmos forms can be disappointing. This is the pick from Wisley because although there were very few doubles, the singles and fluted flowers matched perfectly in colour to create a fascinating, rosy-pink blend. Height 1.8m.

Tall, rather leafy cosmos plants with fresh-green foliage carry single, long-stemmed white flowers, each vividly edged with bright carmine. Some flowers are almost fully white, the variability in the markings adds to the appeal. Height 2m.

These cosmos have cupped flowers with white petals fused into huge bowls, but with some pink-tinted and split flowers. Alternatively, ‘Cupcakes Mixed’ has a balance of white and pink shades. Voted People’s Favourite by Wisley visitors. Height 1.2m.

Deep-red, scarlet or deep-pink single cosmos flowers on tall but prolific plants. Rich colouring and  good with silver foliage, the flowers age harmoniously but eventually need regular deadheading. Height 1.5m. Hardiness RHS H3.

Very pretty cosmos that is a Fleuroselect Gold Medal winner. The small, mostly single, primrose-yellow flowers have a neat, white ring around the golden eye; a few flowers have extra petals and there are a few white flowers. Height 1m.

Like a shorter version of ‘Candy Stripe’, the striking plants are best early and mid-season, while the compact foliage allows the flowers to bloom unhidden. Cruder in colour than the softer, but taller, Cosmos ‘Capriola’. Height 60cm.

One of the best cosmos in the Wisley display, short plants carry rich, carmine single flowers that hold their colour well and fade harmoniously into pinkish tones. Good flower shape and size, ideal in large containers. Height 60cm.

Nicely rippled, rose-pink single cosmos flowers face upward from uniformly neat plants, the colour hardly fading before the petals start to drop. An improvement on the similar, but now unacceptably variable, ‘Sonata Pink’. Height 60cm.

Large, flat, upward-facing, pure-white flowers on plants of uniform height, Cosmos ‘Apollo White’ flowers consistently from June until well into the autumn. The Apollo Series is the new standard in short cosmos. Height 60cm.

Semi-double flowers in vivid reddish orange, with a few orange-flowered plants mixed in. Flowers are sparse at first but prolific later on, and open at various heights on the plant, not only at the top. Height 50cm.

My favourite, the white flowers are exquisite with their unique pattern: each petal on this cosmos is boldly tipped and edged in magenta pink with a similar ring around the eye. Sadly, it can be variable, and there are some ‘off’ types. Height 1.2m.

Perhaps the most dramatic cultivar, white flowers are tipped and streaked in reddish carmine, though some flowers are almost entirely white and some completely carmine. Eventually this cosmos fades to parched pink, when deadheading is necessary. Height 1m.

A new medium-height cultivar with large, mainly semi-double flowers striped in lavender pink and blushed white. Very pretty, early, long-flowering and prolific cosmos, but, strangely, its flowers all face in different directions. Height 1.2m.

Cosmos bipinnatus ‘Versailles Dark Rose’

The best of the tallest types of cosmos; the large, single, rich-rose flowers have a dark-red ring around the golden eye. Too tall and leafy for many gardens, but good at the back of the border and for cutting. Height 2.5m.

You can find more information on hardiness ratings here.

Suppliers

Chiltern Seeds (seeds)
Crowmarsh Battle Barns,
114 Preston Crowmarsh,
Wallingford, Oxfordshire OX10 6SL.
Tel 01491 824675,
chilternseeds.co.uk

Crocus
Online seed and plant supplier.
Tel 01344 578000,
crocus.co.uk

Mr Fothergill’s (seeds and plants)
Gazeley Road, Kentford,
Suffolk CB8 7QB.
Tel 0333 777 3936,
mr-fothergills.co.uk

Plants of Distinction (seeds)
Church Farm Cottage, The Street, Framsden, Near Stowmarket, Suffolk IP14 6HG.
Tel 01449 721720,
plantsofdistinction.co.uk

Thompson & Morgan
Online seed and plant supplier.
Tel 0844 573 1818,
thompson-morgan.com