What are Nasturtiums?
Nasturtiums are a popular choice for many gardeners, celebrated for their vibrant, trumpet-shaped flowers in shades of red, orange, yellow, and pink, as well as their distinctive, shield-shaped leaves. Native to South and Central America, these annual plants (though sometimes perennial in warmer climates) belong to the genus Tropaeolum, and are closely related to the nasturtium oil used in traditional remedies. Their appeal lies not only in their striking visual presence but also in their culinary uses – both the flowers and leaves offer a peppery, slightly tangy flavour, making them a delightful addition to salads and garnishes. They are known for their vigorous growth, often trailing or mounding, and their ability to thrive in less-than-ideal soil conditions, making them a forgiving option for beginners.
- Familiarity: Widely recognised for their bright colours and edible qualities.
- Ease of Care: Generally undemanding, tolerating poorer soils and some neglect.
- Versatility: Suitable for beds, borders, containers, and even as ground cover.
- Edibility: Flowers and leaves add a peppery zest to culinary creations.
Why Choose Nasturtium Plants?
Opting for nasturtiums brings a multitude of benefits to any garden space. Their cheerful blooms provide a splash of colour from early summer until the first frosts, attracting pollinators like bees and butterflies. Unlike many ornamental plants, nasturtiums actively contribute to the garden's ecosystem and can even serve as a trap crop for aphids, luring them away from more vulnerable plants. Their rapid growth means you can enjoy their beauty and flavour relatively quickly after planting. For those seeking plants that offer both aesthetic appeal and functional benefits, nasturtium plants present a compelling, multi-purpose option that enhances visual interest and culinary possibilities.
Understanding Nasturtium Flowers and Their Uses
The allure of nasturtium flowers extends beyond their visual charm. Each bloom is a burst of edible colour, perfect for garnishing dishes. Their peppery taste is similar to watercress, adding a unique zest to salads, sandwiches, and other light meals. The leaves, too, share this distinctive flavour profile and can be used in similar ways, often finely chopped. Beyond the kitchen, nasturtiums are valued for their ability to deter certain pests. They are known to attract aphids away from crops like beans and brassicas, acting as a decoy. This natural pest management characteristic makes them a valuable companion plant in organic gardening. When considering flowering nasturtium varieties, gardeners often look for those that best suit their aesthetic and functional goals, whether for vibrant bedding, cascading container displays, or a culinary herb garden.
Plant nasturtiums in well-drained soil that isn't overly rich; excessive fertility can lead to more foliage and fewer flowers.
Varieties of Nasturtiums
The world of nasturtiums offers a delightful array of forms and colours, catering to diverse gardening preferences. Generally, they fall into two main growth habits: bush varieties and climbing/trailing types. Bush types, like 'Alaska' or 'Cherry Rose', remain more compact, reaching heights of about 30-45 cm, making them ideal for containers, borders, or mass plantings where a neater appearance is desired. These often produce masses of flowers on relatively short stems. In contrast, climbing or trailing nasturtiums, such as 'Moonlight' or 'Jewel of India', can spread vigorously, with vines reaching lengths of up to 2-3 metres. These are excellent for covering walls, trellises, or for spilling over the edges of hanging baskets and raised beds, creating a dramatic, cascading effect. Colour palettes range from the classic bright oranges and yellows to deep scarlets, magentas, and even bi-coloured varieties. Some, like the 'Whirlybird' series, have uniquely upward-facing flowers, ensuring they are always visible.
When selecting nasturtium plants, consider the space available and the desired effect. For a small patio pot, a dwarf bush variety might be best. For a wilder, more abundant display along a fence or wall, a climber will provide coverage and visual impact. The choice between these forms allows gardeners to tailor their nasturtium display precisely to their landscape, ensuring optimal beauty and utility.
Growing Nasturtium Plants: A Gardener's Guide
Cultivating nasturtiums is remarkably straightforward, making them an excellent choice for gardeners of all skill levels. These plants are not particularly fussy, but understanding a few key requirements will maximise their vibrant display and edible yield. Nasturtiums prefer a sunny location, ideally receiving at least six hours of direct sunlight per day, though they can tolerate partial shade. However, in very hot climates, some afternoon shade can prevent scorching and prolong flowering.
Soil and Planting Conditions
The secret to abundant nasturtium flowers often lies in the soil. While they are adaptable, they perform best in well-drained soil. Crucially, they dislike overly rich or heavily manured soil, which can encourage lush foliage at the expense of flowers. In fact, slightly poorer soil often leads to a more prolific bloom. For containers, use a good quality, well-draining potting mix. When planting seeds, sow them directly into the ground or pot after the last frost has passed. Nasturtium seeds are quite large and can be sown about 2-3 cm deep and 15-20 cm apart. They germinate relatively quickly, often within 7-14 days. If starting indoors, sow seeds in biodegradable pots a few weeks before the last frost to avoid disturbing the roots during transplanting, as nasturtiums dislike root disturbance.
Water nasturtiums consistently, especially when young and during dry spells, but allow the soil to dry out slightly between waterings. Avoid overwatering, which can lead to root rot.
Care and Maintenance for Flowering Nasturtiums
Once established, nasturtium plants require minimal care. Regular watering is important, particularly in dry periods, but avoid waterlogging the soil. Deadheading spent flowers isn't strictly necessary as they readily produce new blooms, but it can help maintain a tidier appearance and encourage further flowering. For bush varieties, pinching back young plants can promote a bushier habit. Climbing types may need some support, such as a trellis or netting, as they grow. Nasturtiums are generally disease-resistant, but can occasionally be affected by powdery mildew, especially in humid conditions or when air circulation is poor. Ensuring good spacing between plants can help mitigate this. Aphids can sometimes be a problem; if they appear, a strong jet of water or insecticidal soap can usually manage them, or you can simply leave them for beneficial insects or the plant's trap-crop function.
When to Plant Nasturtium Seeds
The timing for planting nasturtium seeds is crucial for a long flowering season. In temperate climates, nasturtiums are typically sown directly outdoors after all danger of frost has passed. This usually means late spring, from April to June, depending on your specific region. Sowing seeds successively every few weeks can ensure a continuous display of flowers throughout the summer and into autumn. If you wish to get a head start, you can sow seeds indoors in pots about 2-3 weeks before the last expected frost. However, it's important to handle their roots with care when transplanting, as they are sensitive to being moved. For those in milder climates, nasturtiums can sometimes be sown in early autumn for overwintering and early spring blooms.
The plant's resilience means that even if you miss the optimal planting window, nasturtiums are often forgiving and can still provide a good show if sown a little later.
Nasturtiums UK Gardening Considerations
Growing nasturtiums in the UK is generally very successful due to their adaptable nature. They thrive in most garden soils, provided they are well-drained, and prefer a sunny spot. In cooler UK summers, they might appreciate the warmest, sunniest site available. Many gardeners opt for direct sowing from spring onwards, once the soil has warmed and the risk of frost has subsided. The trailing varieties are particularly effective for softening the edges of raised beds or containers, while the bush types fill gaps in herbaceous borders or add vibrant colour to vegetable patches. Their tolerance for less-than-ideal soil conditions also makes them suitable for challenging spots, such as poor, sandy soil.
For those looking to extend their flowering season in the UK, consider sowing seeds in batches a few weeks apart. This ensures a continuous display from early summer right through to the autumn frosts. While they are often grown as annuals, in milder coastal areas, they might survive a winter, though this is not typical nationwide. The edible nature of both the flowers and leaves makes them a favourite for culinary gardeners, adding a peppery kick to salads and dishes throughout the growing period.
Alternative Plants and Companion Planting
While nasturtiums offer a unique combination of beauty, flavour, and pest-deterring qualities, gardeners often explore alternative plants that share some of these characteristics or complement them effectively. Understanding these alternatives allows for greater design flexibility and ecological balance within the garden.
Similar Flowers for Colour and Edibility
If you are drawn to the bright, cheerful colours of nasturtiums, several other annuals and perennials can provide a similar visual impact, though perhaps with different textures or flavours. Marigolds (Tagetes spp.) offer bold, sunny blooms in shades of yellow, orange, and red, and some varieties are also edible, though their flavour is quite distinct. Pansies and violas are smaller but offer a wide spectrum of colours, including purples and blues not found in nasturtiums, and their petals are also edible, with a mild, slightly sweet taste. For a more delicate, wispy effect, cosmos plants provide airy blooms in pinks, whites, and oranges that attract pollinators. Sweet peas, while primarily grown for their fragrance and delicate flowers, offer a beautiful climbing display in a range of pastel and vibrant colours, though they are not typically consumed.
When considering edible flowers, borage, with its star-shaped blue blooms, and calendula (pot marigold) with its sunny orange and yellow petals, are excellent choices that also attract beneficial insects. Each of these alternatives brings its own charm and benefits, allowing gardeners to create layered displays of colour and attract a diverse range of wildlife.
Companion Planting with Nasturtiums
Nasturtiums are renowned for their beneficial companion planting properties, particularly their ability to act as a trap crop for aphids. By planting nasturtiums near susceptible crops like brassicas (cabbage, broccoli, kale), beans, or cucumbers, gardeners can lure aphids away from the main crop, concentrating the pests where they are easier to manage or simply less damaging. This natural pest control method is invaluable for organic gardening. They are also thought to deter squash bugs and some beetles. Therefore, a strategic placement of nasturtium plants throughout the vegetable garden can contribute significantly to overall crop health without resorting to chemical interventions.
Plants to Avoid Near Nasturtiums
While nasturtiums are generally good neighbours, there are a few plants they are best kept separate from. It is often advised not to plant nasturtiums near legumes like peas and beans, not because they harm them, but because nasturtiums can stunt the growth of these specific crops. Some gardeners also suggest avoiding planting them too close to plants that require very rich soil, as the nasturtium's preference for leaner conditions might not be ideal for its neighbours. For instance, while companion planting is beneficial, you wouldn't typically place a nasturtium right at the base of a heavily fertilised tomato plant; rather, you'd use them to deter pests from the broader vicinity of the vegetable patch.
Understanding these relationships helps create a balanced garden ecosystem. For example, if you are growing sweet peas, you might plant them on one side of a trellis and nasturtiums on another, or use nasturtiums to protect nearby brassicas rather than directly alongside the sweet peas.
The principle of companion planting is about creating a diverse, self-regulating garden where different species support each other's growth and resilience.
Alternatives to Trailing Nasturtiums
For gardeners seeking a cascading effect similar to trailing nasturtiums but with different aesthetics or growth habits, several excellent alternatives exist. Sweet peas offer a fragrant, delicate climbing display and are perfect for covering trellises or arches, providing colour and scent throughout the summer. Lobelia, particularly trailing varieties, provides masses of small blue, purple, or white flowers that spill over the edges of pots and hanging baskets, creating a frothy waterfall of colour. Petunias, especially trailing or 'wave' types, offer large, trumpet-shaped blooms in a vast array of colours and are very effective in containers and hanging baskets. For a more robust, foliage-focused trailing effect, consider plants like dichondra 'Silver Falls', which offers masses of silvery, trailing foliage, or certain varieties of fuchsia, known for their beautiful, pendulous flowers and ability to thrive in shadier spots.
Each of these alternatives offers a unique contribution to the garden's design. While they may not provide the peppery taste of nasturtiums, they excel in visual appeal and can fill similar design roles, from softening edges to creating vibrant hanging displays.
Harvesting and Using Nasturtiums
The dual nature of nasturtiums – ornamental and edible – makes them a unique asset in the garden. Harvesting is straightforward, and their peppery flavour can elevate a variety of dishes. Knowing when and how to harvest ensures you get the best from these versatile plants.
When and How to Harvest Nasturtium Flowers and Leaves
Nasturtium flowers can be harvested as soon as they open, typically from early summer until the first frost. For the best flavour and appearance, pick them in the morning after the dew has dried. Gently twist or snip the flower stem just above the calyx (the green leafy part at the base of the flower). Avoid pulling, which can damage the plant. The leaves are also edible and can be harvested throughout the growing season. Young, tender leaves have the mildest flavour. You can snip off outer leaves or pinch back the tips of stems to encourage bushier growth. If you want to collect seeds, allow flowers to mature and develop seed pods, which are also edible when young and green, often pickled like capers.
The edible parts of the nasturtium plant are best used fresh to retain their vibrant colour and distinct peppery flavour.
Culinary Uses for Nasturtium Flowers and Leaves
The peppery, slightly sweet, and sometimes faintly spicy flavour of nasturtiums makes them a delightful culinary ingredient. The flowers are often used whole as a garnish for salads, soups, or appetisers, adding a burst of colour and a unique taste. Think of them as edible jewels scattered across a plate. The leaves, too, can be used similarly to spinach or basil, chopped into sauces, pestos, or folded into omelettes. Their flavour is more pronounced than the flowers, so use them judiciously. Young, tender leaves are ideal for salads, while older leaves can be cooked. Nasturtium seeds, when immature, can be pickled and used as a substitute for capers, offering a sharp, tangy bite. This versatility means that a single nasturtium plant can contribute to multiple courses of a meal, from a fresh salad starter to a zesty garnish.
Preserving Nasturtiums for Later Use
While nasturtiums are best enjoyed fresh, there are ways to preserve their flavour and beauty for later. One popular method is to freeze nasturtium flowers in ice cube trays with a little water. Once frozen, they can be added to drinks, providing a decorative and flavourful element. You can also dry nasturtium leaves, though their peppery quality diminishes significantly upon drying. The dried leaves can be used as a mild seasoning. For a more potent preservation, pickling the immature seed pods, as mentioned, is highly effective, creating a condiment that lasts for a considerable time. Some people also infuse vinegar or oil with nasturtium flowers and leaves, which can be used for dressings or marinades, though the fresh flavour is always superior.
If you have an abundance of nasturtium flowers, consider making a 'nasturtium butter' by finely chopping the petals and mixing them with softened butter, salt, and a little lemon juice for a flavourful spread.
Troubleshooting Common Nasturtium Issues
While generally robust, nasturtiums can encounter a few problems. The most common is excessive leaf growth with few flowers, usually caused by soil that is too rich in nutrients or nitrogen. In such cases, reduce feeding and watering slightly. Powdery mildew can appear on leaves, especially in humid conditions or when plants are overcrowded. Improving air circulation and avoiding overhead watering can help. If aphids become a significant problem, a strong spray of water or an organic insecticidal soap can be effective. Remember that nasturtiums are often planted specifically to attract aphids away from other plants, so a small infestation might be a sign of success rather than a problem. Overwatering can lead to root rot, so ensuring good drainage is paramount. If plants become leggy, pinching them back can encourage a more compact and floriferous habit.