How to Grow Grape Hyacinths in Australia

Grape hyacinth (Muscari armeniacum), in the asparagus family Asparagaceae, is a spring bulb grown for its spikes of blue bells, like upturned bunches of grapes. It flowers from late winter and spreads into drifts by offsets and seed. It suits dappled shade under deciduous trees and grows well in small pots. The mistake to avoid is letting it seed freely: it has escaped gardens in four states and the ACT.

Three mistakes that matter

1. Letting it seed near bushland. Grape hyacinth self-sows freely and escapes through seed and dumped garden waste. Snap off spent spikes before the pods ripen, and never tip bulbs or clippings into bush or over the back fence.
2. Cutting the leaves off early. The leaves keep feeding the bulb for several weeks after flowering, so cutting them while green means fewer spikes next spring. Leave them until they yellow and wither, then trim at ground level.
3. Skipping the chill in a warm garden. Grape hyacinths need a cool winter to flower well. Where winters are mild, as in Brisbane, chill the bulbs in the fridge for 6 to 8 weeks first, as under Planting Bulbs.

When to plant

Plant in autumn once the summer heat has left the soil, from about March to May, with Anzac Day near the middle of the window. In warmer districts, wait until April or plant chilled bulbs straight from the fridge in May or June. One planting keeps flowering for years, because the clumps return and thicken.

Leaves appear within weeks of planting, months before the flowers, and that is normal. Bulbs bought early can wait in a paper bag somewhere cool and dry until the soil cools.

Site, soil and setup

Grape hyacinth grows in almost any soil that drains, from sand to clay.

Clumps stay in one spot for years, so crop rotation does not apply. Dig in fresh compost each time you divide them.

Weed status, state by state

No state bans it, but it has naturalised in south-eastern South Australia, New South Wales, the ACT, Victoria and Tasmania. Wild records include Ballarat, Daylesford and Geelong, the Cooma district and old garden sites across Tasmania. It has also turned up in bushland near central Perth, probably from dumped garden waste. Dig out unwanted plants with every bulb and offset, and put them in the general waste bin, not the compost, where bulbs can survive.

Container growing

A pot keeps this spreading bulb in check and suits warm zones, where it can be moved out of summer rain. Use a pot with drainage holes, at least 20 cm wide and 20 cm deep (about 5 L), and a premium, free-draining potting mix. Crowd 10 to 15 bulbs in close together, not touching, at the same depth as in a bed. Grape hyacinths, 'Heavenly Blue' among them, stand 10 to 20 cm tall, which suits pots.

• Watering. Water in after planting, then whenever the top 2 cm of mix feels dry. Stop once the leaves yellow.
• Feeding. Water in fish and seaweed blend at 25 mL per 9 L as the buds form and again as the flowers fade.
• Position. Full sun or light shade in winter and spring. Move the pot somewhere dry and shaded for the summer rest.

Planting Bulbs

Grape hyacinths start from small dormant bulbs, 15 to 30 mm across, planted pointed end up in autumn.

Chilling

In the Subtropical zone and other mild-winter gardens, chill the bulbs for 6 to 8 weeks before planting. Put them in a paper bag in the fridge crisper. Keep them away from apples and other ripening fruit, whose ethylene gas harms the flowers. Plant them straight from the fridge. Cool and alpine, Mediterranean and most Temperate gardens get enough winter cold without it.

Wear gloves when handling bulbs, and store them where children and pets cannot reach. They are ornamental bulbs, not food, and eating them can cause nausea and vomiting.

The two store varieties

'Heavenly Blue' is the standard blue grape hyacinth, with cobalt blue bells tipped white from July to September on spikes 10 to 20 cm tall. It suits drifts, edging and pots. 'Magic Carpet' is grown the same way.

Planting a drift

1. Prepare the bed as under Site, soil and setup.
2. Plant in groups of ten or more, because single bulbs are lost in the garden.
3. Set each bulb pointed end up, 5 to 10 cm deep, about three times its own height.
4. Space bulbs 5 to 10 cm apart for a dense show, or up to 15 cm apart to leave room to spread.
5. Water in well, then water again only if the soil dries out.
6. Mark the spot, so a spade does not find the bulbs in summer.

After flowering

Snapping off spent spikes, as under Three mistakes, also gives larger spikes next spring. Seedlings that do come up take up to four years to flower. Every four to five years, lift congested clumps while they are dormant in summer, split off the offsets and replant them.

Care by growth stage

Moisture while the leaves are green and a dry summer rest decide how well grape hyacinths flower. Feed lightly: bone meal at planting, then a liquid feed as the buds form and again as the flowers fade.

If growth stalls in poor soil, a light dose of all-purpose controlled release granular (NPK around 14-5-10) scratched in as the leaves appear can help.

Companion planting

Grape hyacinths make a low blue carpet beneath taller spring bulbs and early perennials.

Grows well with

• Daffodils, which flower alongside and go in at the same autumn planting.
• Pansies, low company for grape hyacinths in a pot.
• Hellebores, which flower at the same time and hide the bulbs' fading leaves.

Keep apart

• Bush and reserve edges, where seed and dumped bulbs escape into native vegetation.
• Fine lawns, which grape hyacinth seeds itself into.
• Small rock-garden plants that a spreading clump can crowd out.

Harvesting Blooms

Cut a spike when its lowest bells have opened and the top ones are still tight, because each spike opens from the bottom up.

• Cut in the cool of the morning.
• Cut the stem at its base and leave every leaf on the plant.
• Stand the stems straight in water.
• Pick from the back of a clump so the display stays full.

In the garden a spike stays in flower for about two weeks. Bulbs lifted for dividing can go straight back in, or wait in a paper bag somewhere cool, dry and airy until autumn. Use the cut stems in posies and small vases, where their scent and colour carry well.

Common problems

Plenty of leaves, few flowers. Crowded clumps and deep shade both reduce flowering; divide clumps when dormant and move them into more light. For warm-winter gardens, see Three mistakes.

Untidy leaves in autumn and winter. Long, floppy leaves before and after flowering are normal for this species; plant among low perennials that hide them.

Soft, rotting bulbs. Bulbs rot when planted too deep or in a wet site; replant firm bulbs at 5 to 10 cm in free-draining soil or a pot.

Bulbs dug up. The smell of bone meal and other organic fertilisers draws dogs to dig. Fence the bed, or feed with the controlled release granular under Care by growth stage in place of bone meal.

Pests and diseases

Grape hyacinth is generally free of pests and diseases, so watch mainly for snails in damp weather.

Garden snail (Cornu aspersum). Widespread in Australian gardens, snails and slugs feed on the soft leaves and flowers of spring bulbs in damp weather. Hand-pick on damp evenings, or scatter an iron-based bait thinly by its label, never in heaps, where dogs cannot reach the pellets or packet. Read more

Prevention first

• Buy and plant only firm, plump bulbs, and discard any that are soft or mouldy.
• Plant in free-draining soil, so bulbs do not sit wet.
• Check new leaves and buds on damp winter evenings for snails.
• Clear the withered leaves once they have fully died down.

Tips

1. For a river of blue, plant a long, winding drift under deciduous trees, like the famous Blue River planting at Keukenhof in the Netherlands.
2. The leaves show in autumn, so they mark where clumps sit when you plant other bulbs around them.
3. If you cannot tell which end is up, plant the bulb on its side and the shoot finds its own way.

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