How to Grow Scilla in Australia

Woodland bluebells, sold as Scilla, are Spanish bluebell (Hyacinthoides hispanica), a spring bulb in the asparagus family (Asparagaceae) once named Scilla hispanica. A different plant from hyacinths (Hyacinthus) and grape hyacinths (Muscari), they are grown for upright spikes of bell-shaped flowers in part shade. Bluebells return and spread each spring in cool and temperate gardens, but in warm districts the bulbs need chilling first.

Three mistakes that matter

1. Skipping the chill in a warm district. Bluebells need a cold winter to flower well, so in Brisbane or on the NSW north coast flowering is often patchy. Chill the bulbs in the fridge for 6 to 8 weeks first, as described under Planting Bulbs.
2. Planting into wet, heavy soil. Bulbs sitting in waterlogged ground over winter rot before they flower. Choose a well-drained spot, dig compost through clay before planting, or grow them in a pot of potting mix instead.
3. Cutting the leaves off after flowering. The yellowing leaves are feeding the bulb for next spring, so removing them early means fewer flowers. Leave them for 4 to 8 weeks until they wither, and hold off mowing bluebells in a lawn.

When to plant

Plant in autumn, once the nights turn cool: from March in cold districts, and in April or May where winters are mild. Roots grow while the soil still holds some warmth, so plant by the end of May. Anzac Day falls in the middle of the window. One planting lasts for years, because the clumps multiply.

In warm districts, count back 6 to 8 weeks from your planting day and start the chill then.

Site, soil and setup

Bluebells are woodland plants: they want winter and spring light, then shade and a dry rest over summer.

A clump stays put for years, so crop rotation does not apply.

Weed status by state

Spanish bluebell spreads by seed and by offsets (small bulbs that form beside the parent). In Victoria it occasionally escapes from gardens, often as a hybrid with English bluebell (Hyacinthoides non-scripta).

No state declares it, but keep it in the garden. Cut spent stems before seed sets near bushland (see Harvesting Blooms), and put unwanted bulbs in the green waste bin rather than the home compost.

Container growing

Pots suit bluebells and keep their seed and offsets in check. Use a pot at least 20 cm wide, about 4.5 L, for around 10 bulbs, or 25 cm wide, about 8.5 L, for around 15. Choose one with drainage holes, fill it with premium potting mix and set the bulbs close together, a little shallower than in the ground.

• Watering. Water in, keep the mix just moist from first shoots to the end of flowering, then let it dry out over summer.
• Feeding. Give seaweed solution at 30 mL per 9 L once a fortnight from first shoots until the leaves yellow.
• Position. Bright shade or morning sun, out of hot afternoon sun once buds show.
• Repotting. Lift and repot crowded bulbs as described under Harvesting Blooms.

Planting Bulbs

Bluebells start from dormant bulbs planted straight into the ground or a pot in autumn.

Chilling

In subtropical and other warm districts, give the bulbs a false winter before planting. Put them in a paper bag in the fridge crisper for 6 to 8 weeks. Keep fruit out of that fridge, because the ethylene gas it gives off can ruin the flower buds. Plant them straight from the fridge. Cool and temperate gardens can skip the chill altogether.

Planting in the ground

• Choose firm, plump bulbs, and set aside any that are soft, mouldy or squashy.
• Dig holes 7 to 10 cm deep and set each bulb pointed end up.
• Space bulbs 10 to 15 cm apart in loose drifts, or scatter a handful and plant them where they land.
• Backfill, water in well to settle the soil, then mulch with 5 cm of compost to hold moisture and keep weeds down.
• Mark the spot with a stake, so a spade does not find the bulbs in summer.
• Leaves usually appear through winter, and flowers follow from about August to October, later in cold districts.

Care by growth stage

Moisture while they grow and a dry summer rest decide how well bluebells flower. Feed lightly, because compost and bone meal at planting carry them most of the way.

Weeks run from an autumn planting, so let the plants mark each stage. If growth stays weak in poor soil, a light dose of all-purpose controlled release granular (NPK around 14-5-10), scratched in as shoots appear, can help.

Companion planting

Bluebells do best among plants that shade them in summer and hide their fading leaves.

Grows well with

• Deciduous trees, which let in winter and spring light, then shade the resting bulbs in summer.
• Hellebores, which grow early and help hide the dying bulb leaves.
• Jonquils and snowflakes, hardy bulbs that also stay in the ground for years.

Keep apart

• Vegetable beds, where a bulb could be dug up and eaten by mistake.
• Small, slow perennials and ground covers, which spreading bluebell clumps can smother.
• Bushland edges, where seed and dumped bulbs can escape into native vegetation.

Harvesting Blooms

Pick stems for the vase when they stand firm with every bell well attached, before any begin to drop.

• Snap or cut each stem at the base rather than pulling it, which can damage the bulb.
• Strip any leaves that would sit below the waterline, and recut the stem end with a sharp knife.
• Stand stems in water with flower food.
• Keep pets away from the vase water, because every part of the plant is poisonous.
• Cut stems left in the garden as the bells fade, to stop seed forming.

The bulbs are best left in the ground, but crowded clumps can be lifted every three to four years once the leaves have died down. Replant them straight away, or store them dry in old stockings or mesh bags in an airy shed and replant in autumn.

Common problems

Leaves but few flowers. In warm districts the bulbs have missed their winter chill (see Three mistakes that matter). In cooler gardens, deep shade is the usual cause.

Soft, rotting bulbs. Bulbs that were soft, brown or smelly when bought already carried disease, and wet ground finishes the job (see Three mistakes that matter). Read more

Fewer flowers each year. Clumps crowd themselves after a few years. Lift and divide them in summer, as described under Harvesting Blooms.

Bluebells coming up everywhere. Seed from spent stems and new offsets spread them through a bed. Cut spent stems (see Harvesting Blooms), and fork out strays while they are dormant.

Pests and diseases

Bluebells are generally free of serious pests and diseases, so one pest does most of the damage.

Common garden snail (Cornu aspersum). Snails and slugs chew holes in young leaves and flowers, mostly on wet nights. They hide by day, so go out after dark with a torch and pick them off. Read more

Prevention first

• Sink a shallow container of beer among the clumps to trap snails and slugs.
• Line pots and raised beds with copper tape, which snails and slugs dislike crossing.
• Drop collected snails into soapy water rather than squashing them, because their eggs can survive.
• Welcome kookaburras, magpies and frogs, which eat snails.

Tips

1. Plant a few bulbs inside an old colander or open basket, so they are easy to find and lift later.
2. Grow bulbs in a plain pot set inside a better-looking outer pot, then lift it out to die down out of sight once flowering ends.
3. Check the botanical name on any label: bluebell creeper (Billardiera) is an unrelated climber and a declared plant in South Australia.

Due to quarantine restrictions and our shipping policy, we cannot send Scilla bulbs to Western Australia or Tasmania.