How to grow Nasturtiums

You will often find that Nasturtiums are given the name Tropaeolum. And depending on whether they are bushy/dwarf varieties or climbing varieties, they are named Tropaeolum minus or Tropaeolum majus respectively.

Additionally, other varieties include Tropaeolum azureum, Tropaeolum peregrinum, Tropaeolum speciosum, Tropaeolum tricolor and more.

The more common name, Nasturtium, comes from the Latin translation ‘nose twister’. This is because Renaissance botanists compared its taste and spicy scent to that of watercress, which is named Nasturtium officinale.

Nasturtiums are native to South America, specifically to the Andes Mountains, where they are considered an invasive species outside its typical range.

This depends on which variety you grow. Tropaeolum minus is a bushy/dwarf variety, which grows well in containers and the front of borders. Tropaeolum majus is a climbing variety, often seen as trained on wigwams or other tall structures or as ground cover.

They can be seen with either simple or ovate, circular leaves that palmate, with bright funnel-shaped flowers featuring 5 petals each.

Nasturtiums grow in a rewarding number of colours, some of these even combined in mottled, marbled, or bicolour designs.

The colours you’re most likely to see from Nasturtiums include orange, red, yellow, cream, pink, dark red, bright red, and salmon. When growing from seed, check the packet so you know which colours to expect.

These colourful plants need sunlight for at least half of the day to grow well, so choose a sunny spot.

Free-draining soil is best, and not too fertile. If it is too fertile, the plant will grow predominantly foliage, which may bury the blooms, hiding them.

Nasturtiums do fine in rich, fertile soil, however they tend to grow masses of foliage compared to less blooms. This is why they grow better in poor soils generally.

Moist soil is also not so great for Nasturtiums, preferring soil that drains well.

Know which Nasturtium you’re growing, first and foremost. Climbing Nasturtiums will grow in different places to dwarf/bushy Nasturtiums, so keep that in mind when planting.

You can expect to see their flowers emerging from June all the way through to October. This gets you through most of the summer, and autumn, until the first frosts.

Nasturtiums are notoriously easy to grow. So easy, in fact, that they are often given to children to grow! And because all parts of Nasturtiums are safe to ingest, this means children can grow them from a young age.

These plants are often annuals, which means they need to be sown again every year to see them come back. They live for as long as they flower, then die back during the frosts.

Yes, Nasturiums are really good plants for a pollinator-friendly garden. Their bright and various colours are very attractive to pollinators, plus their trumpet-shaped flowers give easy access to the nectar and pollen.

The main two categories of Nasturtium are bushy, or trailing/climbing. Choosing which of these two varieties you would like to grow is probably the easiest place to start!

Bushy or dwarf Nasturtium varieties are ideal for growing in containers and at the front of borders. Their flowers are bright and eye-catching, and they don’t grow particularly tall, most only growing up to 30 cm (1 foot) tall.

Climbing or trailing Nasturtium varieties are a great choice for a few different options. They can be trained to grow up wigwams, supports, obelisks, or another vertical surface. As they also trail, they make a great choice for ground cover too. They will even spread across gravel or paved surfaces for some bright colour! Trailing varieties also grow well in pots, and they have a lovely chandelier effect in hanging baskets.

Again, this depends completely on which variety you choose to grow.

Tropaeolum minus typically won’t grow much taller than 30 cm (1 foot), and the same goes for the spread of these varieties.

Alternatively, Tropaeolum majus will, like T. minus, grow not much more than 30 cm tall (1 foot) unless climbing. Its spread can be much larger, with some varieties growing up to 1.5 metres (5 feet).

Before sowing or planting, you want to make sure that the area is weed-free, and well-draining soil. Rake the surface to a fine tilth and produce seed drills 2cm deep. Each drill should be about 30 cm (1 foot) apart.

If you’re growing your Nasturtiums from seed, you want to sow them between March and May. You can do this exactly where you want them to grow, or in 9 cm pots in a greenhouse or windowsill. Use free-draining soil for this.

If you’re planting out established Nasturtiums, you can do this anytime from May to August, again in free-draining soil.

Nasturtiums are extremely low maintenance, so don’t need much from you once sown or planted.

Once the seedlings have emerged, you can thin them out to make sure they are no closer than 30 cm apart.

If you are growing your Nasturtiums in the ground, they are unlikely to need regular watering. In containers, you should check that the soil is moist, but not sodden.

It’s best not to feed Nasturtiums! Feeding will lead to masses of foliage growth and fewer blooms.

Nasturtiums are typically grown from seed. You can harvest these from the plant in late summer or early autumn but wait until the last minute. You want to ensure that the seeds are mature! They can dry and fall off the plant, or you can collect them yourself. The seeds are the size of a large pea, and there will be roughly 2-4 of them per flowerhead.

Leave them out on a paper towel to dry, then store in a cool, dry place. Then you can plant them next year!

It is not uncommon to see large and small white butterflies laying their eggs on Nasturtium leaves. These eggs develop into caterpillars. That is why Nasturtiums are often planted among crops you would prefer the caterpillars to leave alone, as Nasturtiums recover well.

If you don’t really want your Nasturtiums eaten by caterpillars, the best thing to do is try to move them if you can to a plant you don’t mind being nibbled. Caterpillars are valuable to our gardens, as both moths and butterflies are important pollinators.

Nasturtiums can also be affected by aphids, which is why they are often planted amongst aphid-vulnerable crops. If you’re growing for Nasturtium flowers, encourage aphid predators like ladybirds, hoverflies, and lacewings into your garden.

Young annual or perennial plants can be bought from the garden centre and from nurseries between late spring and early summer, ready to plant out straight away.

Seeds can be bought year-round from your local garden centre too, to plant out in the spring.

The best garden styles for Nasturtiums to feature in, include City and Courtyard, Gravel and Rock, Informal, and Cottage garden designs.