Keter Manor Outdoor Apex Double Door Garden Storage Shed (6 x 8ft)
A durable and stylish beige and brown garden storage shed perfect for storing garden tools, equipment, bikes, and outdoor essentials. Weather-resistant, low maintenance, and ideal for any garden or allotment setup.
Seed Trays & Propagation Kits
View Seed Trays
Heated Propagators & Grow Lights
See Grow Lights
Seed Compost for Healthy Seedlings
View Compost
🌸🌱 March Flower Planting Guide: What to Grow in the UK for Seasonal Blooms
🌿 Introduction: Why March Is a Key Month for Flowers
March marks the true start of the growing season in the UK. Days are getting longer, soil is beginning to warm, and many flowers can now be sown either indoors or directly outdoors. Planting flowers in March sets the stage for vibrant spring, summer, and even autumn displays.
Gardeners plant flowers in March because:
✔ soil conditions are improving
✔ frost risk is reducing (but not gone)
✔ plants establish before summer heat
✔ it allows for a longer flowering season
This guide explains exactly what flowers to plant in March in the UK, plus where and how to grow them successfully.
Below
⭐ Check Out Our Recommended Products
• Flower Seeds for Spring Sowing
Choose hardy and half-hardy varieties suited to March planting.
Click here to see them
• Seed Trays & Module Pots
Ideal for starting flowers indoors or under cover.
Click here to see them
• Multi-Purpose or Seed Compost
Provides the right balance for healthy germination.
Click here to see them
🌸🧠 1. What Flowers Can Be Planted in March?
March is suitable for:
✔ hardy annuals
✔ half-hardy annuals (under cover)
✔ perennials from seed
✔ bulbs and tubers
Where you plant depends on frost risk and flower type.
🌱🌼 2. Hardy Annual Flowers to Sow Outdoors in March
These flowers tolerate cool conditions and light frost.
✔ sweet peas
✔ calendula (pot marigold)
✔ cornflowers
✔ nigella (love-in-a-mist)
✔ larkspur
✔ poppies
Sow directly into prepared soil in sunny positions.
🌸🏡 3. Half-Hardy Annuals to Sow Indoors in March
Start these under cover to protect from frost.
✔ cosmos
✔ zinnias
✔ sunflowers
✔ nasturtiums
✔ cleome
✔ annual salvias
These will be planted outside after the last frost.
🌱🌿 4. Perennial Flowers to Start in March
March is ideal for many perennials grown from seed.
✔ delphiniums
✔ lupins
✔ echinacea
✔ rudbeckia
✔ aquilegia
Perennials take longer but reward patience with long-term colour.
🌷🌱 5. Bulbs and Tubers to Plant in March
Some summer-flowering bulbs and tubers can go in now.
✔ gladioli (later in March)
✔ lilies
✔ begonias (start indoors)
✔ dahlias (start under cover)
Wait until soil is workable and not waterlogged.
🌞🌱 6. Best Places to Grow March-Sown Flowers
✔ sunny borders
✔ raised beds
✔ containers and pots
✔ greenhouses or cold frames
Good drainage is essential at this time of year.
💧🌱 7. Watering and Care for March Plantings
✔ keep compost moist, not wet
✔ water gently to avoid seed displacement
✔ protect young plants from frost
Overwatering is a common early-season mistake.
🌱✋ 8. Hardening Off March-Sown Flowers
Before planting outside:
✔ gradually expose plants to outdoor conditions
✔ do this over 7–10 days
✔ avoid frost and strong winds
Hardening off reduces transplant shock.
⚠️❌ 9. Common Mistakes When Planting Flowers in March
❌ sowing too early outdoors
❌ ignoring frost forecasts
❌ planting into cold, wet soil
❌ overcrowding seedlings
Patience is key in early spring.
🌸📅 10. What Blooms to Expect from March Planting
✔ spring sowings bloom from late spring onwards
✔ many flower all summer
✔ some self-seed for next year
March planting creates long-lasting seasonal colour.
🌟 FAQs
Is March too early to plant flowers in the UK?
No — many flowers thrive when planted in March.
Do I need to protect plants from frost?
Yes — especially half-hardy annuals.
Can I sow flowers directly outside in March?
Yes — hardy annuals can be sown outdoors.
What flowers grow fastest from March sowing?
Cosmos, calendula, and cornflowers grow quickly.
Should I use seed compost or multi-purpose compost?
Seed compost is best for germination.
Meta Description:
March flower planting guide for the UK. Learn what flowers to grow in March, including hardy and half-hardy annuals, perennials, and bulbs, plus where to sow them, indoor vs outdoor planting advice, frost protection tips, and common mistakes to avoid for beautiful seasonal blooms.