Spring Bulbs to Grow Now

March is an exciting time in the garden. Whether you’re planting summer-flowering bulbs outdoors or getting a head start indoors, there’s plenty to be getting on with. This guide covers what to plant, how to do it, and what to expect.

Understanding the Two Types of “Spring” Bulbs

When gardeners talk about spring bulbs, they usually mean one of two things:

Spring-flowering bulbs (tulips, daffodils, alliums) are planted in autumn and bloom in spring. If you missed that window, don’t worry — you can often find pre-chilled or “in the green” bulbs at garden centres right now that can go straight into the ground.

Summer-flowering bulbs (dahlias, gladioli, begonias, cannas) are planted in spring — which means now is exactly the right time. These are the focus of the planting section below.

Bulbs to Plant Outdoors Now (March–April)

Dahlias

Dahlias are one of the most rewarding summer bulbs you can grow. The tubers can go in the ground from mid-March onwards in mild areas, though in colder parts of the UK it’s safer to wait until late April or start them off in pots indoors.

Planting depth: 10–15 cm deep
Spacing: 60–90 cm apart (they get big)
Position: Full sun, sheltered from wind
Soil: Rich, well-drained
Tips: Add a generous amount of compost to the planting hole. Place a stake before planting to avoid damaging the tuber later. They won’t tolerate frost, so have fleece ready if a late cold snap is forecast.
When to expect flowers: July through to the first frosts

Gladioli

Gladioli produce tall, architectural spikes of flowers and are perfect for cutting. Plant corms in successive batches every two weeks from now until May to enjoy a long season of blooms.

Planting depth: 10 cm
Spacing: 10–15 cm apart
Position: Full sun
Soil: Well-drained; they rot in waterlogged conditions
Tips: Plant in rows for a cut-flower patch, or dotted through borders for vertical interest. In colder regions, lift corms in autumn and store them frost-free over winter.
When to expect flowers: 70–90 days after planting

Eucomis (Pineapple Lily)

An underused gem. Eucomis produces exotic-looking flower spikes topped with a tuft of leaves — like a miniature pineapple. They thrive in a sunny, sheltered spot and are surprisingly hardy once established.

Planting depth: 10 cm
Spacing: 30 cm apart
Position: Full sun, against a south-facing wall if possible
When to expect flowers: August–September

Crocosmia

Crocosmia (including the popular cultivar ‘Lucifer’) produces fiery orange-red flowers beloved by hummingbirds and bees. The corms multiply quickly, making them great value.

Planting depth: 8–10 cm
Spacing: 8–10 cm apart
Position: Full sun to partial shade
Tips: Plant in clumps for the best visual impact. Divide congested clumps every few years to maintain vigour.
When to expect flowers: July–August

Begonias (Tuberous)

Tuberous begonias are ideal for pots, hanging baskets, and shaded spots where other summer bulbs struggle. They come in a dazzling range of colours.

Planting: Start tubers indoors now (see below) or plant directly outdoors from late May after the last frost
Position: Partial shade to full shade
Tips: Plant tubers hollow-side up. They need very little water until growth appears.
When to expect flowers: June–October

Cannas

Cannas bring a tropical feel with their large paddle-shaped leaves and vivid flowers. They need a warm start, so get them going indoors now.

Planting: Start in pots indoors from March, plant out after the last frost (late May/early June)
Position: Full sun, sheltered
When to expect flowers: July–September

Bulbs to Start Indoors Now

Starting bulbs indoors in March gives you earlier flowers and a longer season — particularly important in cooler regions.

How to Start Dahlias Indoors

Place tubers in trays or pots of barely moist compost, with the crown (the end with the old stem) just above the surface.
Keep in a frost-free greenhouse, conservatory, or windowsill at around 15°C.
Water sparingly until shoots appear, then water more regularly.
Harden off before planting out after the last frost.

How to Start Begonias Indoors

Fill a shallow tray with moist compost or moist vermiculite.
Press tubers hollow-side up, half-submerged in the medium.
Keep at 18–21°C in good light.
Once shoots are several centimetres tall and roots have developed, pot on individually.

How to Start Cannas Indoors

Soak rhizomes in warm water for 24 hours to break dormancy.
Plant in large pots of multipurpose compost.
Water well and keep warm (18°C+).
Harden off thoroughly before planting outside.

Buying “In the Green” Spring-Flowering Bulbs

If you missed autumn planting but still want daffodils, snowdrops, or bluebells this year, look for bulbs sold “in the green” — these are actively growing plants lifted just after flowering and sold with their foliage still attached. They transplant far better than dormant bulbs planted out of season.

Snowdrops in the green are widely available and are actually the preferred way to establish new colonies. Plant immediately after purchase, at the same depth they were growing.
Bluebells in the green establish well and will naturalise in woodland or partial shade.
Daffodils in the green can also be found, though they’re less common.

Essential Growing Tips

Soil Preparation

Most bulbs demand good drainage above all else. If your soil is heavy clay, improve it by digging in grit and well-rotted compost. Raised beds and containers are excellent alternatives for problem soils.

Planting Depth

A useful rule of thumb: plant bulbs at a depth of two to three times their diameter. Deeper planting offers some protection against frost and helps anchor tall-growing bulbs like dahlias and gladioli.

Feeding

Summer-flowering bulbs are hungry plants. Once foliage is growing strongly, feed every two weeks with a high-potassium liquid fertiliser (such as tomato feed) to encourage flowering rather than leafy growth.

Watering

Water at planting, then hold back until growth appears. Once in active growth, keep soil consistently moist but never waterlogged. Containers dry out quickly and will need daily checking in warm weather.

Frost Protection

The main risk in March and April is unexpected late frosts. Keep horticultural fleece to hand and be ready to cover tender growth overnight. Established foliage can usually tolerate light frosts; young shoots and emerging growth are more vulnerable.

Pests and Problems to Watch For

Slugs and snails are the biggest threat to emerging bulb shoots in spring. Use biological control (nematodes), copper rings, or go out at night with a torch to remove them by hand.

Vine weevil attacks begonia and dahlia tubers, particularly in containers. The white grubs eat roots and tubers from below. Use a biological nematode treatment watered into the compost in spring.

Dahlia aphids gather on soft new growth. Blast off with water or use an organic insecticidal soap spray.

Botrytis (grey mould) can affect bulbs started indoors in cool, humid conditions. Ensure good ventilation and avoid overwatering.

What to Expect Month by Month

March: Start dahlias, cannas, and begonias indoors. Plant gladioli corms in mild areas. Buy snowdrops and bluebells in the green.

April: Plant gladioli outdoors in succession. Harden off indoor-started dahlias and cannas. Plant crocosmia and eucomis outside.

May: Plant out hardened-off dahlias, cannas, and begonias after the last frost. Continue succession planting of gladioli.

June onwards: Maintain feeding and watering. Stake tall dahlias and gladioli. Deadhead regularly to extend flowering.

Top Varieties to Look For

Dahlia: ‘Bishop of Llandaff’ (dark foliage, red flowers), ‘Café au Lait’ (blush tones, hugely popular), ‘David Howard’ (apricot, orange)
Gladiolus: ‘Plum Tart’ (deep purple), ‘Espresso’ (dark maroon), ‘White Prosperity’ (classic white)
Crocosmia: ‘Lucifer’ (bold red), ‘Emily McKenzie’ (orange with mahogany markings)
Begonia: ‘Non Stop’ series (compact, prolific), ‘Illumination’ series (ideal for hanging baskets)
Canna: ‘Tropicanna’ (striped foliage, orange flowers), ‘Wyoming’ (bronze foliage, orange flowers)