Adding cosmos to the White Garden

Adding Cosmos to the White Garden

It's mid-May, and time to plant out this key annual, which will provide colour right up to the first frosts. Let's look at how to grow and plant cosmos, and how it fits into the planting scheme in the White Garden.

• Cosmos (a half-hardy annual) can be planted out as soon as the risk of frosts is over, often mid-May in southern England or early June in northern or cooler areas of the UK.
• Cosmos are a great way of building up layers of planting for succession.

May Planting in the White Garden

The planting in the White Garden is swirls of textures and tones flowing around key trees and shrubs:

• emergent perennials – foxgloves, overwintered snapdragons
• mid-layer of perennials with self-seeded ox-eye daisies running through
• pockets where wallflowers were in spring – now they've finished, I'm planting cosmos 'Purity' in the gaps.

Growing and Planting Cosmos

• We sowed our cosmos on 18th March, and they're ready to plant out in mid-May.
• Roots are just starting to emerge from the pot, indicating they're ready for planting.
• Plants will establish more quickly if planted as soon as the risk of frosts is over, when the soil is warm enough but also still moist.
• We pinch out the growing tips around a month after sowing to promote stockier, well-branched plants.
• Allow at least 40cm between plants. They will grow to 5ft tall and bushy.
• Minimise standing on the soil – place them roughly from the side of the bed and then position them more accurately when you go in to plant.
• Plant a little deeper than they are in the pot, to anchor them and avoid the need for staking.
• Keep deadheading to keep them flowering until the first frosts.

Slugs and Snails

• Slugs and snails can damage young plants, so you can pick off any you find on them.
• However, remember that more widely, they are crucial parts of the ecosystem with a host of garden benefits such as decomposing waste, removing algae and recycling nutrients.
• Only a small minority of the UK's slug and snail species feed on live plants.

Plant Directory

Antirrhinum majus cultivars

Snapdragons

Tender, short-lived herbaceous perennials, often grown as annuals

Plantaginaceae

Cosmos bipinnatus 'Purity'

Cosmea 'Purity'

Half-hardy annual

Asteraceae

Digitalis purpurea f. albiflora

White-flowered foxglove

Hardy herbaceous biennial or short-lived perennial

Plantaginaceae

Erysimum species and cultivars

Wallflowers

Hardy or sometimes half-hardy annuals, biennials or woody-based perennials

Brassicaceae

Leucanthemum vulgare

Ox-eye daisy

Hardy herbaceous perennial

Asteraceae