Nasturtium Flowering Times: What to Expect
Nasturtiums are beloved for their cheerful, trumpet-shaped flowers and edible leaves. A common question for gardeners is precisely when do nasturtiums flower? Generally, you can expect your nasturtium plants to start producing their vibrant blooms approximately 4 to 8 weeks after sowing the seeds. This means that if you sow them directly outdoors after the last frost in spring, you'll often see the first flowers appearing from early to mid-summer.
The flowering period for nasturtiums is impressively long, typically lasting from the start of summer right up until the first hard frost of autumn. This extended display makes them a fantastic choice for adding continuous colour to borders, containers, and even vegetable patches, as they are known companions for certain crops.
- Nasturtiums flower 4-8 weeks after sowing.
- Blooming starts in early to mid-summer.
- Flowering continues until the first frost.
- Care and variety influence bloom timing.
Several factors influence this timing, including the specific variety of nasturtium you are growing, the planting conditions, and the overall care the plant receives. Understanding these elements can help you maximise the blooming period and enjoy these striking flowers for as long as possible.
When to Sow for Early Flowers
To encourage an early show of nasturtium flowers, it's best to sow seeds directly into the soil once the risk of frost has passed. In many UK climates, this is typically from April or May onwards. Nasturtiums are not keen on being transplanted, so direct sowing is usually the preferred method. If you sow them in early to mid-May, you can realistically look forward to flowers appearing from July onwards.
For an even earlier start, or if you have a particularly short growing season, you can start nasturtium seeds indoors about 3-4 weeks before your last expected frost date. Use biodegradable pots to minimise root disturbance when transplanting them outside after the danger of cold weather has gone. This method can bring the first blooms forward into late June.
Factors Influencing Nasturtium Bloom
While the general timeline for nasturtium flowering is well-established, several conditions can either accelerate or delay their bloom, and affect the sheer abundance of flowers produced. Ensuring the right environment is key to unlocking their full floral potential.
Sunlight Requirements
Nasturtiums thrive in full sun. Ideally, they should receive at least 6-8 hours of direct sunlight per day. Ample sunlight is crucial not only for robust growth but also for prolific flowering. Plants grown in shadier spots may become leggy with fewer blooms, focusing their energy on leaf production rather than flowers. If your nasturtiums are not flowering as expected, assess their sun exposure. Moving pots to a sunnier location or ensuring they are planted in a bright garden bed can make a significant difference.
Soil Conditions and Feeding
Nasturtiums prefer well-drained soil that isn't overly rich. In fact, they perform best in poorer soils. Overly fertile soil, especially one high in nitrogen, can encourage lush foliage growth at the expense of flowers. If you've planted them in very rich compost or fed them with a high-nitrogen fertiliser, they might be producing lots of leaves but few flowers. For optimal flowering, avoid excessive feeding. A light application of a balanced, low-nitrogen fertiliser might be beneficial only if the soil is exceptionally poor, but often, no additional feeding is required.
If your nasturtiums are producing abundant foliage but sparse flowers, try withholding fertiliser and ensure they have good sun exposure. Sometimes, a slightly stressed plant (in terms of soil fertility) will prioritise flowering.
Watering Habits
Consistent watering is important, especially when plants are young and during dry spells. However, nasturtiums are relatively drought-tolerant once established and can even benefit from slightly drier conditions, which can encourage flowering. Overwatering, much like overly rich soil, can lead to excessive leaf growth and fewer flowers. Aim for soil that is moist but not waterlogged. Allow the top inch of soil to dry out between waterings, particularly once the plants are mature and flowering.
Deadheading and Pruning
Regular deadheading – removing spent flowers – can encourage the plant to produce more blooms. As flowers fade, they develop into seed pods. If left on the plant, the nasturtium will channel its energy into producing seeds rather than more flowers. Simply pinch or snip off the faded blooms. For trailing varieties that might become a bit unruly, a light trim can help maintain their shape and encourage bushier growth, potentially leading to more flowering sites.
The key to a long nasturtium flowering season lies in balancing their need for sunlight with avoiding overly rich soil and excessive watering.
Nasturtium Varieties and Their Flowering Habits
Nasturtiums come in a delightful array of varieties, each offering slightly different growth habits and bloom times, though the core flowering period remains consistent. Understanding these differences can help you choose the best types for your garden's aesthetic and your specific timing goals.
Trailing Nasturtiums
Varieties such as 'Alaska' (known for its variegated foliage), 'Moonlight', and 'Jewel' are typically trailing or climbing types. These are ideal for spilling over the edges of hanging baskets and containers, or for rambling through trellises and walls. They generally produce a profusion of flowers over a long season, often starting a little later than bush types but continuing just as robustly until the frost.
Bush Nasturtiums
Bush varieties, like 'Cherry Rose', 'Salmon Queen', or the compact 'Whirlybird' series, grow into more rounded, upright mounds. These are excellent for planting in beds and borders where their compact form is beneficial. They often start flowering slightly earlier than their trailing counterparts and provide a dense display of colour. Their overall bloom duration is similar, but their habit means the visual impact is more concentrated.
Comparing Bloom Times with Other Flowers
When considering when do nasturtiums flower, it’s useful to compare their timeline with other popular garden annuals. Sweet peas, for instance, often bloom earlier in the season, from late spring, and their flowering might wane by mid-summer if not managed carefully. Marigolds can begin blooming around the same time as nasturtiums, from early summer, and often continue through to autumn with similar resilience. Sunflowers, planted from seed, typically take longer to mature before blooming, often appearing in mid to late summer depending on the variety and planting time.
Fuchsias, which are often perennial in milder climates but grown as annuals elsewhere, have a different flowering habit, often starting later in summer and continuing into autumn, and they tolerate more shade than nasturtiums. Begonias, another popular choice for colour, can bloom from spring through to autumn, but many prefer partial shade, making them a different option for certain garden spots. Geraniums (Pelargoniums) offer a long blooming season from late spring into autumn, provided they are fed and deadheaded, and also have varied preferences for sun and soil compared to nasturtiums.
For continuous colour through summer and autumn, pair nasturtiums with plants that have slightly different peak blooming times or cultural needs. For example, early-blooming sweet peas followed by nasturtiums, and then late-blooming dahlias or asters, can create a succession of interest.
Nasturtium Species and Variations
The most commonly grown species is *Tropaeolum majus*. Within this species, there are many cultivars bred for different flower colours (ranging from pale yellow and apricot to deep crimson), leaf patterns (like the variegated 'Alaska'), and growth habits (bushy vs. trailing). While specific cultivars might have marginal differences in their exact readiness to flower, the general rule of thumb—4-8 weeks post-sowing—holds true for most varieties of *Tropaeolum majus*.
Maximising Your Nasturtium's Flowering Potential
To ensure your nasturtiums provide a spectacular display from early summer until the first frost, a few horticultural practices can significantly enhance their blooming performance. It’s not just about planting them; it’s about nurturing them to fulfil their flowering potential.
The Importance of Planting Time
As mentioned, timing is crucial. Direct sowing after the last frost (typically May in the UK) is the most reliable method for most gardeners. This allows the plant to establish its root system in warm soil, setting the stage for a prompt start to flowering in July. If you are aiming for the earliest possible blooms, consider starting seeds indoors in late April or early May, being mindful of their dislike for root disturbance.
Companion Planting Benefits
Nasturtiums are excellent companion plants, particularly in vegetable gardens. Their peppery scent can deter certain pests like aphids and whiteflies, and they are thought to act as a trap crop for some undesirable insects. This pest-deterring quality indirectly benefits their flowering by keeping the plant healthier and less stressed, allowing it to direct more energy into bloom production. Consider planting them near beans, brassicas, or cucumbers.
Container vs. Ground Planting
Nasturtiums can be grown successfully in both containers and garden beds. In containers, ensure the pot is of adequate size (at least 20-25 cm diameter) and has good drainage. Plants in pots may require more frequent watering, especially during hot weather, but this also gives you greater control over soil conditions. Growing them in containers with less fertile potting mix can naturally encourage more flowers and less foliage. In the ground, they perform best in well-drained soil without the addition of excessive compost or manure.
When to Expect the Last Blooms
The end of the flowering season for nasturtiums is dictated by the weather. They are tender annuals and will not survive a frost. However, they are remarkably resilient and will continue to produce flowers right up until temperatures drop significantly. In most of the UK, this means you can enjoy their blooms well into October, and sometimes even November in milder years or sheltered locations. As soon as a hard frost is forecast, their flowering will cease, and the plants will begin to die back.
By adhering to these practices, you can ensure a vibrant and extended flowering period for your nasturtiums, transforming your garden with their bold colours and cheerful disposition throughout the warmer months.