Nasturtium

Overview

Nasturtiums are almost foolproof: big seeds that small hands can sow, rapid growth and bright flowers in orange, red, yellow and cream all summer. The round leaves and flowers have a peppery, watercress flavour and liven up salads, and the green seeds can be pickled. 'Empress of India' has dark leaves and crimson flowers, 'Alaska' has cream-splashed foliage, 'Tom Thumb' types stay compact, and trailing or climbing varieties will scramble up a fence or tumble from a basket.

Where to grow nasturtium

Sunny, lean ground gives the most flowers. They are ideal for edging vegetable beds, filling gaps on new allotments, trailing over walls and planting in pots or hanging baskets. In shade or rich soil they grow lush but bloom sparsely.

Planting

Sow seeds 2cm deep directly where they are to grow from mid-May, once frosts are over. For earlier flowers, sow in small pots indoors in April and plant out after hardening off. Space compact types about 30cm apart and climbers a little further.

Care through the year

Spring

Sow under cover or wait for warm soil. Protect young plants from late frost.

Summer

Water only in long dry spells and skip the fertiliser. Pick flowers and leaves freely, and check undersides of leaves for pests.

Autumn

Plants keep flowering until the first frost. Collect ripe seeds to sow next year.

Winter

Clear frosted plants. Self-sown seeds may sprout next spring.

Pruning

No pruning needed. Trim straggly trailing stems to keep them in bounds and pull out plants that wander too far.

Propagation

Grow from seed. Collect the large, wrinkled seeds when they turn pale and fall easily, dry them and store them in a paper bag. Nasturtiums often self-seed.

Common problems

Blackfly cluster on stems and leaves, and caterpillars of the large cabbage white butterfly can strip plants. Some gardeners use them as a sacrificial crop to draw pests away from brassicas. Squash blackfly with your fingers or hose them off, and pick off caterpillars by hand.

Guides to the problems most likely to affect nasturtium:

• Aphids
• Cabbage caterpillars

Something else wrong? Diagnose it by symptom.

Month-by-month reminders

Jobs for this plant come round in May and June. Each month page lists everything else worth doing in the garden at the same time.

Related plants

• Pot marigold
• Sunflower
• Sweet pea

Sources

Botanical names follow Kew's Plants of the World Online; growing attributes were checked against the references below. Text is our own. See our editorial policy.

• Kew Plants of the World Online — Tropaeolum majus
• Wikipedia — Tropaeolum majus