Nasturtiums (Tropaeolum) are one of the quickest and easiest annuals to grow. They produce masses of vividly coloured blooms from midsummer right through to the first autumn frosts in a surprisingly wide range of colours – not just orange, yellow and red but also cream, salmon pink, burgundy and crimson (and often a mix of several of these). Some have attractively marbled or mottled leaves, too.
Nasturtiums are either bushy or dwarf (Tropaeolum minus) or climbers (Tropaeolum majus). Bushy varieties look great in containers and hanging baskets or at the front of a border, while climbing varieties can be trained up wigwams or obelisks and will twine through other plants. These can also be used as ground cover, spreading across gravel or cascading down a slope or bank. Both types grow very well in pots.
Nasturtiums not only look spectacular but the flowers, leaves and seeds are edible, too; nasturtiums are also known as Indian cress. Nasturtiums also make good companion plants on the veg patch – the caterpillars of large and small white butterflies feed on the leaves, luring them away from brassicas, while blackfly are attracted to the leaves, which may mean your beans escape attack. Bees love the flowers. Nasturtiums are incredibly easy to grow from seed, making them ideal for beginner gardeners and children. They also make good cut flowers.
How to grow nasturtiums
Sow nasturtiums from March to May, where they are to flower, or in 9cm pots in a greenhouse. Free-draining soil is essential for nasturtiums and, unlike many other flowers, they thrive on poor soils. Water plant in containers in dry spells. Once they have been hit by frosts, dig them up and put them on the compost heap.
Nasturtiums: jump links
- When to sow nasturtiums
- How to sow nasturtiums
- How to plant out nasturtiums
- How to care for nasturtiums
- Harvesting and storage
- Nasturtiums: problem-solving
- Nasturtiums to grow
Where to grow nasturtiums
Nasturtiums need sunshine for at least half the day in order to grow well. A free-draining soil is essential; nasturtiums flower best on poor soils. Fertile soil results in lots of leafy growth at the expense of flowers and flowers that are buried beneath the foliage.
Grow nasturtiums at the front of a border, up an obelisk, as companion planting on the veg patch or spilling over the edge of raised beds and pots.
When to sow nasturtium
Sow nasturtium seeds under cover from March and outside when the soil has warmed up, from March to May – a late sowing will ensure flowers until the first frosts.
How to sow nasturtium seeds
Sowing nasturtiums in the ground
You can sow nasturtium seeds directly where they are to flower.
- Rake the soil to a fine tilth and make sure it is free of weeds. Water the area before you sow – this will ensure that you don’t wash away the seeds once sown
- Sow the seeds 1.5cm deep, around 10cm apart – either push them in with your finger, or use a bamboo cane to make a shallow drill
- Cover the seeds with soil
- Once the seedlings emerge (after about two weeks) thin them to around 30cm apart
You can also simply pop seeds around the garden, where you’d like them to appear – around the edge of raised beds or large pots of bedding, for example.
Sowing nasturtiums in pots
You can also sow nasturtium seeds in pots – this is a good way to get earlier flowers and is a good option if you want to plant up a beautiful container display later in the season. Simply sow one seed per 9cm pot in a greenhouse or on a sunny windowsill, harden off and plant outside in late spring.
Read our detailed advice on how to sow annual climbers.
How to plant out nasturtiums
If you haven’t grown your own plants from seed, you might find small pots of nasturtiums at the garden centre in late spring or early summer that are ready for planting out.
Planting nasturtiums in the ground
Dig a hole that is the same size as the pot your plant was growing in, and plant so that the crown of leaves is at soil level. Water in well.
Planting nasturtiums in containers
Mix two-thirds peat-free multipurpose compost with one third fine gravel or grit, to reduce fertility and ensure good drainage. Again, plant so that the crown of leaves is at soil level and water in well.
In this clip from Gardeners’ World, Monty Don arranges plants for a late summer display, with a dramatic purple-leaved Phormium cookianum ‘Black Adder’ in the centre, lots of magenta-flowered Cosmos bipinnatus ‘Dazzler’, and four Bidens ‘Hawaiian Flare Orange Drop’ cascading over the rim, alongside trailing nasturtiums, Tropaeolum majus ‘Cherry Rose Jewel’. He also advises on aftercare to keep the display at peak flowering through to late autumn:
How to care for nasturtium
Nasturtiums are easy to care for and need little maintenance. Plants growing in the ground rarely need watering. Plants growing in containers should be watered to keep the compost evenly moist, but don’t feed them. Deadheading will encourage more blooms over a longer period.
Harvesting and storage
Nasturtium leaves, flowers and seeds are all edible. The flowers and young leaves have a peppery taste (nasturtiums are closely related to watercress) and are a great addition to salads. The seed pods can be used as a substitute for capers (they are known as ‘poor man’s capers’). Pick them when mature but still green, and pickle them in vinegar.
You can collect nasturtium seeds when they’re ripe and save them somewhere cool and dry to sow next year. In mild areas, nasturtiums are also likely to self-sow, so you may get seedlings springing up in future years. These can be easily pulled up if not wanted.
Growing nasturtiums: problem solving
Nasturtiums are likely to attract large and small white butterflies (known as cabbage white butterflies) which lay their large greenish eggs on the leaf undersides, which hatch into caterpillars that eat the leaves. This can be useful to deter caterpillars from eating brassica crops but not desirable if you’re growing nasturtiums for flowers. The best method of control is to inspect plants regularly and squash the eggs or young caterpillars, or move them on to plants you don’t mind being eaten.
Nasturtiums are also attractive to aphids, particularly blackfly. Again, by planting nasturtiums alongside bean crops you can lure aphids away from your crop, but you may not appreciate aphids on nasturtiums you’re growing for leaves and flowers. Spray them off with a jet of water or let ladybirds, hoverflies and lacewings remove them for you – all three lay their eggs on aphid colonies and their young quickly eat them up.
Nasturtium varieties to grow
Nasturtium ‘Black Velvet’
Tropaeolum minus ‘Black Velvet’ is a compact nasturtium with velvety dark red flowers. H x S: 30cm x 45cm
Tropaeolum minus ‘Phoenix’ has flowers with unusual split petals, in shades red, orange and yellow. A bushy variety. Height x Spread: 30cm x 30cm
Nasturtium ‘Empress of India’
Nasturtium minus ‘Empress of India’ is a bushy nasturtium with crimson-red flowers and dark leaves. H x S: 25cm x 45cm. ‘Princess of India’ is a dwarf version.
Nasturtium ‘Orange Troika’
Tropaeolum majus ‘Orange Troika’ is a climbing or trailing variety with vivid orange flowers and marbled foliage. H x S: 30cm x 1.5m
Nasturtium ‘Alaska Series’
Nasturtium minus ‘Alaska Series’ produces flowers in yellow, cream, orange and red, shown off against cream and green marbled leaves. Bushy. H x S: 25cm x 45cm.
Tropaeolum minus ‘Ladybird’ has pretty cream/yellow flowers with deep red spots at the throat. H x S: 30cm x 40cm
Nasturtium ‘Baby Deep Rose’
Tropaeolum minus ‘Baby Deep Rose’ is a compact, bushy variety with deep crimson blooms. H x S: 20cm x 20cm
Nasturtium ‘Bloody Mary’
Tropaeolum minus ‘Bloody Mary’ has splotched and striped flowers in shades deep red, yellow and cream. H x S: 30cm x 60cm