How to grow and care for cleome

Grow spider flower in full sun and in fertile, well-drained soil. Site it where plants are sheltered from wind as the tall stems are susceptible to damage. Good sites include the middle to back of a border, mixed with other colourful annuals to create a summer bedding display, or in gaps in borders amongst permanent plants. Due to its tall growth, spider flower isn’t ideal for pots apart from large containers.

How to plant cleome

Harden off plants growing under cover to acclimatise them to the outside for 10-14 days before planting out in early summer once the frosts are past. Water in immediately after planting.

Caring for cleome

After planting out, keep watered for the first few weeks until established and then water regularly during dry spells. Stake or support plants as stems grow tall and flower heads form. Fortnightly throughout summer, apply a liquid fertilizer high in potash to boost flowering. Deadhead faded blooms to encourage more flowers.

How to propagate cleome

Start seeds under cover in February/March, sowing onto moist seed compost and covering with a fine layer of perlite or vermiculite. Keep at a temperature of 20°C for seed to germinate reliably. Once the seedlings are large enough to handle, transplant into individual pots and grow on until sufficiently large to plant out, in early summer.

Pests and diseases of cleome

Young plants are susceptible to slug and snail damage. Minimise risk of damage by growing plants to a good size in pots before planting out, then using an environmentally friendly barrier protection to combat pests.

As a brassica, cleome foliage may be eaten by the caterpillars of large and small white butterflies. Inspect leaf undersides regularly, hand pick caterpillars, and transfer them to a sacrificial crop of nasturtiums, instead.