Nasturtium (Tropaeolum (group))

Overview

The Nasturtium, represented by the adaptable Tropaeolum (group) genus, remains a vibrant staple in gardens globally due to its vibrant hues and quick growth habit. These warm-weather annuals offer a stunning display of funnel-shaped blooms, typically in rich shades of red, orange, yellow, or cream, making them invaluable for adding immediate color to beds and containers. Gardeners prize Nasturtium not only for its aesthetic appeal but also for its surprising utility, as nearly all parts of the plant are edible, offering a pleasant, peppery bite.

As popular members of the Tropaeolaceae family, Tropaeolum (group) plants are famously forgiving, tolerating poor soils and periods of dryness once established. They come in both sprawling, dwarf bushy forms and impressive climbing varieties, allowing for flexible placement within the landscape. Whether cascading over a wall or scrambling up a trellis, the unique, parasol-like foliage provides a lush backdrop to the spicy, showy flowers.

This ease of care, combined with robust flowering from spring through autumn, solidifies the Nasturtium’s reputation as a gardener favorite. For best results, aim for full sun exposure, though some afternoon shade is beneficial in extremely hot climates, ensuring this cheerful annual provides continuous visual interest throughout the growing season.

Fast Facts

• Plant Family: Tropaeolaceae
• Plant Type: Annual
• Hardiness Zones: USDA Zones 2-11
• Size at Maturity:
  • Height: 1-10 ft
  • Spread: 1-3 ft
• Bloom Time: May to September
• Bloom Description: Red, orange, yellow or cream
• Sun Exposure: Full sun
• Water Needs: Medium
• Maintenance Level: Low

How to Grow

Sow Nasturtium seed directly into the garden after the danger of spring frost has passed, or start them indoors in pots about four to six weeks prior. These Tropaeolum (group) plants prefer poor to average, well-drained soils, and surprisingly, richer media tends to encourage excessive leaf growth at the expense of flowers. While they enjoy full sun, provide some part afternoon shade in hot summer areas to prevent stress during prolonged heat waves.

Watering needs for Tropaeolum (group) are moderate, but they exhibit tolerance for drier soil conditions, which can actually enhance flower production. It is crucial to avoid heavy fertilization; excess nutrients are known to decrease blooming significantly. Nasturtium are renowned for being forgiving annuals that manage well with minimal intervention.

Plants will readily self-seed if allowed to mature, potentially providing volunteers the following spring. Climbing types require support, such as a trellis or fence, to reach their full height potential, usually between 6 to 10 feet. Keep an eye out for common pests like aphids, though serious disease issues are rare for this hardy plant.

Landscape Uses

The diversity within the Tropaeolum (group) genus allows for a wide array of landscape applications. Dwarf-bushy, sprawling types excel as border edgings, softening the hard lines of pathways or cascading effectively over retaining walls. These low-growing varieties also function beautifully as dense, colorful annual ground covers across sunny slopes.

For dramatic vertical interest, utilize the climbing specimens by training them along fences or decorative trellises, transforming bare structures into a living tapestry of blooms. Furthermore, the compact nature of many modern Nasturtium selections makes them outstanding choices for mixed containers and hanging baskets, where their trailing habits are fully displayed.

Every part of the Nasturtium plant is usable, making them suitable for integrating into herb gardens, not just flower borders. Their peppery flavor makes them a standout addition to salads, linking the edible garden seamlessly with ornamental displays.

Standout Features

Flower Qualities

• Showy
• Fragrant

Noteworthy Characteristics

Nasturtiums are warm weather annuals that have been popular in herb gardens, cottage gardens and flower gardens for many years. Cultivars and hybrids sold under the name of Tropaeolum majus are generally referred to as common nasturtiums or garden nasturtiums. These plants exhibit showy, long-stalked, funnel-shaped flowers up to 2.5 inches wide that attract hummingbirds. The genus name itself references classical trophies, fitting for such a visually dramatic plant.

Tolerances

• Deer

Potential Problems

Nasturtium rarely suffer from serious insect or disease issues, contributing to their low maintenance status. However, gardeners should remain vigilant for soft-bodied pests such as aphids, mealybugs, and whiteflies, particularly when grown in hot, humid conditions.

If pests appear, immediate action is often effective. A strong spray of water can dislodge aphids from foliage, or in more persistent cases, insecticidal soap can be carefully applied. Overwatering or planting in heavy, poorly draining soils should be avoided as this increases susceptibility to fungal issues rather than pest pressure.

Frequently Asked Questions

What hardiness zones is Nasturtium suitable for?

This dependable annual is suitable for a very wide range of climates, thriving in USDA Zones 2 through 11.

How large does Nasturtium grow?

Depending on the variety, the mature height can range significantly from a low ground cover of 1 foot up to climbing types reaching 10 feet tall, with spreads generally between 1 and 3 feet.

What sun exposure does Tropaeolum (group) need?

For the best flower production, Nasturtium requires full sun exposure, although they appreciate relief from intense afternoon heat in the hottest parts of their range.

When does Nasturtium bloom?

This vigorous annual flowers consistently from May all the way through September, displaying blooms in shades of red, orange, yellow or cream.

Conclusion

The Nasturtium (Tropaeolum (group)) offers exceptional value through its ease of growth, edible components, and continuous, brilliant summer color. Its remarkable tolerance for neglect and its versatility in both climbing and sprawling habits make it a practical choice for nearly any gardener looking to maximize visual impact quickly. Before planting, swiftly check your local frost dates to ensure you start your seeds at the optimal time for a long blooming season.

Companion Planting

When planning your garden layout, consider companions that appreciate similar growing habits or that can help manage common pests associated with leafy, lush plants. Because Nasturtium thrives in slightly leaner, well-drained soil, pairing them with heavy feeders might require careful segregation during fertilization schedules.

Marigolds are traditional companions, as their strong scents are often cited as beneficial in deterring certain garden nuisances which might otherwise bother the Tropaeolum (group) foliage. Similarly, planting them near vegetable crops can act as a sacrificial trap crop or simply provide beautiful contrasting color.

In cottage garden settings, allow the Nasturtium to intertwine with sturdy, upright companions like cosmos or snapdragons. The trailing habit of the dwarf Nasturtium acts as a living mulch, suppressing weeds underneath taller flowers while adding necessary texture diversity.

Wildlife Benefits

While the primary benefit of Nasturtium often centers on its edible qualities, the funnel-shaped flowers are highly sought after by specific members of the local ecosystem. Their vibrant, nectar-rich blooms are particularly attractive to hummingbirds, who easily access the nectar hidden within the spurs.

These bright colors signal richly rewarding snacks to avian visitors throughout the peak summer months when many other early bloomers have faded. This reliable nectar source ensures that even in simpler annual displays, you are supporting essential garden pollinators.

Although not a primary pollinator plant like true milkweeds, the open structure of the Tropaeolum (group) flower allows for easy access by various smaller bees moving between flowers, contributing generally to the biodiversity of your sunny border or container arrangement.