As tulips and daffodils begin to brighten gardens with their vibrant hues, late March presents an ideal opportunity for gardeners to look ahead. With the harshest winter weather hopefully behind us, this period is perfect for sowing hardy annuals outdoors. These colourful, fast-growing plants help bridge the gap between spring bulbs and summer perennials, ensuring a continuous display of blooms.
Why Sow Hardy Annuals Now?
Sowing seeds in late March allows plants to develop a strong, deep root system while the soil remains moist from spring rains. This timing also enhances resilience, as the young plants adapt to variable weather conditions, including wind, rain, and temperature dips, making them tougher than those grown under cover. Additionally, early blooming flowers provide essential food for emerging bees and butterflies, boosting garden biodiversity throughout the year.
Six Fast-Growing Flowers to Plant This Month
Here are six hardy annuals that can be sown directly outside in late March and will flower in record time. For those preferring a head start, French marigolds, petunias, and zinnias can be begun indoors and transplanted later.
1. Calendula (Pot Marigold)
Unlike French marigolds, calendula tolerates cooler temperatures and can be sown directly outdoors. Simply rake the soil, scatter the seeds, cover lightly, and expect blooms in six to eight weeks. This daisy-like plant is edible, perfect for salads, and often self-seeds, returning year after year without extra cost.
2. Nasturtiums
Known for their vigorous growth, nasturtiums typically flower within 60 days when sown in late March, unless frost persists. They thrive in poor soil—rich soil may produce more leaves than flowers. These plants are excellent for pollinators, and both leaves and flowers offer a peppery, edible flavour.
3. Cornflowers
Cornflowers provide a striking electric blue colour and can be sown directly into containers, beds, or borders, blooming in eight to ten weeks. They grow well in poor soil, attract bees, and make beautiful cut flowers. Pair them with wildflowers like poppies and cosmos for a stunning display.
4. Nigella (Love-in-a-Mist)
Nigella is famously tough, with feathery foliage and blue or white flowers. It dislikes transplanting, so sow seeds directly where you want them to grow. The plant self-seeds readily, and its unique striped seed pods are ideal for drying and decorative use.
5. California Poppies
These vigorous, spreading annuals, often in orange or yellow, flower within 60 days. Like nigella, they prefer direct sowing in sunny spots and thrive in poor or sandy soil. Once established, they are highly drought-tolerant, making them low-maintenance choices.
6. Sweet Alyssum
Sweet alyssum forms a low-growing carpet of honey-scented flowers, perfect for edging pots or paths. It blooms in six to eight weeks when seeds are scattered on the soil surface, as they need light to germinate. The flowers attract hoverflies, which help control aphid populations, benefiting your garden ecosystem.
By planting these hardy annuals now, you can enjoy a colourful, biodiverse garden that flourishes from spring into summer. Remember to check local conditions and adjust sowing times if frost is still a risk.
