Tropaeolum tricolor, commonly known as the Three-coloured Nasturtium or Three-coloured Indian Cress, is an unusual tuberous perennial climber producing masses of brilliantly coloured flowers in red, purple and yellow. Its exceptionally slender twining stems weave through supports and neighbouring plants, creating a delicate curtain of foliage and exotic, long-spurred blooms.

Unlike familiar annual nasturtiums, Tropaeolum tricolor follows an unusual winter-growing and summer-dormant cycle. The stems emerge from an underground tuber during the cooler months, with flowering continuing from winter into spring or early summer before the plant naturally dies back for its summer rest.

• Botanical name: Tropaeolum tricolor
• Common names: Three-coloured Nasturtium, Three-coloured Indian Cress
• Plant type: Tuberous perennial climber
• Flower colour: Orange-red, purple and yellow
• Flowering time: Winter to early summer
• Height: Approximately 1.5m
• Spread: Approximately 30-60cm when trained
• Position: Bright position with sun or light shade
• Soil: Fertile, very well-drained soil or compost
• Dormancy: Summer dormant
• Ideal for: Conservatories, cool greenhouses, sheltered walls and containers with climbing support

About Tropaeolum tricolor

Native to Chile, Tropaeolum tricolor is one of the most distinctive members of the nasturtium family. From the tuber emerge exceptionally fine, thread-like stems bearing small, light green leaves divided into five or seven rounded lobes.

The flowers are the real attraction. Each is around 3cm long, with an orange-red calyx tipped in deep purple surrounding a contrasting yellow flower. A slender red to purple spur extends behind the bloom, producing the extraordinary three-coloured effect that gives the species its name.

A Delicate Climber

Despite the fine appearance of its stems, this species can climb to around 1.5m tall when given suitable support. Fine mesh, twiggy branches or slender canes work particularly well because the delicate stems need something narrow to twine through.

Its airy growth makes it ideal where a conventional vigorous climber would be too heavy. The flowers are most effective when the stems are allowed to scramble naturally through an open framework.

Where to Grow Tropaeolum tricolor

In the UK, Tropaeolum tricolor is best grown somewhere sheltered from hard frost and excessive winter wet. A cool greenhouse, conservatory or protected container makes it much easier to accommodate its winter-growing habit.

Provide plenty of light and excellent drainage. The tuber dislikes sitting in cold, waterlogged compost, particularly when dormant.

How to Plant Tropaeolum tricolor Tubers

Plant the tuber in a deep pot filled with a fertile but sharply draining compost. A mix containing additional grit or perlite is useful. Cover the tuber with several centimetres of compost and provide a climbing support from the start, as the new shoots can develop quickly once growth begins.

Water cautiously at first, increasing slightly once strong growth is visible. During active growth, keep the compost lightly moist but never saturated.

Winter Growth and Summer Dormancy

The unusual seasonal cycle is important when growing this species. Tropaeolum tricolor normally grows through the cooler part of the year, flowers from winter into spring or early summer, then naturally begins to yellow and die back.

Once the foliage has died, reduce watering significantly during summer dormancy. The resting tuber should be kept comparatively dry until signs of fresh growth return.

Height and Spread

When supported, Tropaeolum tricolor usually climbs to around 1.5m tall. Its individual stems are extremely slender, with an approximate trained spread of 30-60cm, depending on the support provided and the maturity of the tuber.

Why Grow Tropaeolum tricolor?

• Extraordinary three-coloured flowers
• Bright orange-red, purple and yellow colouring
• Delicate thread-like climbing stems
• Unusual winter-growing habit
• Flowers when relatively few climbers are in bloom
• Reaches approximately 1.5m tall
• Spread of around 30-60cm when trained
• Returns from a perennial underground tuber
• Excellent collector's plant for protected cultivation

Frequently Asked Questions

How tall does Tropaeolum tricolor grow?
It is a delicate climber capable of reaching approximately 1.5m tall with suitable support.

What is its spread?
When trained, allow approximately 30-60cm, although the fine stems can be directed over a wider support if required.

When does Tropaeolum tricolor flower?
It typically flowers from winter through spring and into early summer before entering dormancy.

Is Tropaeolum tricolor related to ordinary nasturtiums?
Yes. It belongs to the same genus, Tropaeolum, but unlike commonly grown annual nasturtiums it is a perennial climber growing from a tuber.

Does it need climbing support?
Yes. The very slender stems climb most effectively through fine mesh, twiggy supports or thin canes.

Is Tropaeolum tricolor hardy in the UK?
It is best treated as a plant for protected or very sheltered cultivation in the UK, particularly because its active growing period occurs during winter when frost and excessive wet can be damaging.

What happens in summer?
The plant naturally dies back into its underground tuber and becomes dormant. Water should be greatly reduced during this resting period.

With its fine climbing stems and extraordinary red, purple and yellow flowers, Tropaeolum tricolor is a fascinating and highly distinctive tuberous climber for gardeners who enjoy unusual plants and seasonal growth cycles.