HORTICULTURAL SECTOR — As the soil begins to warm this March, gardeners across the region are shifting their focus from spring maintenance to the critical window for summer-flowering bulbs. This month serves as a pivotal transition, offering the final opportunity to rectify missed autumn plantings through “in the green” specimens while simultaneously starting tender summer favorites like dahlias and begonias indoors. Experts suggest that early preparation during this period is the most significant factor in ensuring a vibrant, continuous floral display from mid-summer until the first frost of autumn.
The Two Pillars of Seasonal Bulbs
Understanding the distinction between bulb categories is essential for success. While spring-blooming varieties such as tulips and daffodils are typically planted in the autumn, those who missed the window can still find “in the green” plants. These are actively growing specimens lifted post-flowering, which transplant more successfully than dormant bulbs at this time of year. Specifically, snowdrops and bluebells established now will naturalize more effectively for future seasons.
Conversely, March is the optimal time to begin summer-flowering varieties. These plants, ranging from the architectural majesty of gladioli to the exotic flair of pineapples lilies, require the warming temperatures of spring to establish their root systems.
Strategic Outdoor Planting
For those gardening in milder climates, several varieties can go directly into the ground from mid-March through April. Dahlias remain a cornerstone of the summer garden, requiring rich soil and a planting depth of 10–15 cm. Given their substantial size, spacing them 60–90 cm apart is vital for air circulation.
Gladioli offer a different strategic advantage. By planting corms in two-week intervals from now until May, gardeners can ensure a succession of blooms rather than a single, short-lived flush. Other reliable outdoor options include the fiery, bee-friendly Crocosmia and the exotic Eucomis, which provides a unique architectural element in late summer with its pineapple-shaped blossoms.
The Advantage of an Early Indoor Start
In cooler regions, or for those seeking an extended blooming season, starting tender bulbs indoors is a professional standard. This “head start” method is particularly effective for:
- Tuberous Begonias: These should be placed hollow-side up in moist compost indoors to provide color for shaded areas where other bulbs might struggle.
- Cannas: These tropical giants benefit from a 24-hour warm water soak to break dormancy before being potted and kept at temperatures above 18°C.
- Dahlias: Starting tubers in pots on a frost-free windowsill or greenhouse in March allows for stronger plants that can be “hardened off” and moved outdoors once the threat of frost has passed in late May.
Protecting Your Investment
Success depends heavily on soil management and pest control. Most summer bulbs are susceptible to rot in waterlogged ground; if working with heavy clay, gardeners should incorporate grit and organic matter to improve drainage. A general rule for planting depth is to bury the bulb two to three times its own diameter to provide structural support and frost protection.
As new shoots emerge, vigilance against slugs and snails is paramount. Using biological controls like nematodes or physical barriers can prevent these pests from decimate young growth. Furthermore, as the plants mature, switching to a high-potassium liquid fertilizer—such as tomato feed—every fortnight will prioritize flower production over leaf growth, resulting in a more spectacular display come July.