How to Grow Zephyranthes in Australia

Rain lilies (Zephyranthes), also called zephyr lilies or storm lilies, are small bulbs in the family Amaryllidaceae. They are grown for starry, crocus-like flowers that open a few days after rain. They come from the Americas and suit Australian gardens with summer storms, from Brisbane to Sydney. A dry spell followed by a good soaking brings on the flowers, so beds kept wet all year often give leaves instead.

Three mistakes that matter

1. Planting into cold, soggy ground. Dormant bulbs sitting in waterlogged soil through winter can rot. Choose a free-draining bed, or raise heavy clay and work in coarse grit before planting, as set out under Site, soil and setup.
2. Too much shade. In deep shade the clumps grow thin, flower poorly and are more prone to pests. Give them full sun, or morning sun with afternoon shade in hot inland gardens.
3. Splitting clumps too often. Rain lilies flower best as thick, undisturbed clumps, and single bulbs take longer to reach flowering size. Leave a planting for three to four years, then lift and replant in groups of three or more bulbs.

When to plant

Plant dormant bulbs from late winter into spring, once frosts have passed. Roots then settle before the summer and autumn rains. In frost-free gardens a second window opens in late summer. Potted clumps already in leaf can go in at any time of year if watered in well.

Site, soil and setup

Drainage decides whether the bulbs last. Rain lilies take sand, loam or clay, but they rot where water lies around a dormant bulb in cold weather.

A clump stays put for years, so rotation does not apply. Where water pools after rain, read waterlogged soil before planting.

Choosing a rain lily

Two species are widely grown in Australia, and they differ in colour and in how much cold they take.

Weed status, state by state

Both species have escaped from gardens in eastern Australia. White rain lily is recorded as naturalised in Queensland and New South Wales, and sparingly in Victoria. Pink rain lily is naturalised on the NSW north coast and in eastern Queensland. Neither is a declared weed in any state or territory.

Keep plantings away from bushland, creeks and drains, where seed and bulbs can spread.

Container growing

Rain lilies suit pots, and a wide, shallow bowl planted thickly makes a good show. Use a pot or bowl at least 25 cm wide and 15 cm deep, about 5 L, with drainage holes. Fill it with premium potting mix blended three parts to one with coarse grit, and set the bulbs one bulb width apart.

• Watering. Keep the mix moist, not wet, while in leaf, and water regularly in hot weather. See watering pots in summer.
• Feeding. Water in liquid potash at the label rate every fortnight from the first flowers until late autumn.
• Position. Full sun, with afternoon shade in hot districts. In cool zones, move the pot to a frost-free spot for winter and keep the mix barely moist.

Planting Bulbs

Start from bulbs or divided clumps; seed works too but takes longer to reach flowering size.

Choosing bulbs

Rain lily bulbs are small, from about 1 cm to more than 5 cm across depending on the species. Choose firm bulbs and discard any that are soft or mouldy. Potted clumps in leaf establish and flower faster than dormant bulbs.

Planting dormant bulbs

1. Prepare the bed as under Site, soil and setup, and wear gloves, because the bulbs are poisonous.
2. Set each bulb with its pointed tip upwards, 5 to 8 cm deep.
3. Space bulbs 8 to 10 cm apart, in drifts of ten or more rather than single rows.
4. Firm the soil and water in with seaweed solution at 30 mL per 9 L.
5. Keep the soil just moist until leaves appear, then water as under Care by growth stage.

Dividing a clump

Lift a crowded clump with a fork as growth starts in late winter or spring. It falls apart into many small bulbs. Replant them in groups of three or more at the same depth, as in dividing perennials.

From seed

Seed pods ripen soon after flowering. Sow the shiny black seed fresh, because it loses viability quickly, on moist seed raising mix and cover it lightly. Seedlings usually emerge in two to six weeks and can flower within eight to twelve months in good conditions.

Care by growth stage

Water decides the display, though a hose never sets off flowers quite as well as rain. Feed lightly, because established clumps in fair soil need little.

If growth stalls in poor sand, a light dose of all-purpose controlled release granular (NPK around 14-5-10) scratched in each spring can help.

Companion planting

The grassy leaves stay low, so pair rain lilies with plants that will not smother them.

Grows well with

• Mondo grass and liriope, whose similar leaves hide the bulbs between flushes.
• Star jasmine and other low groundcovers that leave the flowers room to rise.
• Other bulbs, because the rain lily foliage sets off their flowers.

Keep apart

• Vegetable beds, because the leaves can be mistaken for leek or garlic chives.
• Dense, tall perennials and shrubs, whose shade cuts flowering.
• Lawns that are fed and mown short; bulbs naturalised in grass need the mower set high and no lawn feed.

Harvesting Blooms

Each flower lasts only a day or two, so enjoy most of them in the garden. Cut a few as buds show colour for a small vase or a posy.

• Cut in the cool of early morning, at the base of the stem.
• Pick off faded flowers at the base to stop seed setting and spreading.
• Keep cut stems and bulbs away from children and pets.

Stand cut stems in clean water straight away. Lifted or newly bought bulbs keep for a short time in a cool, dry, airy place, but plant them as soon as you can. Every part of the plant, bulb included, contains lycorine and related alkaloids. Eaten, they can cause vomiting, diarrhoea and convulsions, so rain lilies are grown for ornament only.

Common problems

Leaves but no flowers. Soil kept wet with no dry spell is a common cause; otherwise check Three mistakes that matter.

Soft, rotting bulbs. Cold, waterlogged soil through winter; replant sound bulbs in a raised or gritty bed.

Leaves dying down in summer. A long dry spell sends rain lilies dormant, and they regrow after rain.

Scorched leaves in extreme heat. Hot afternoon sun can burn the foliage and cut flowering, so give hot clumps afternoon shade.

Seedlings popping up away from the clump. Seed has ripened and spread, so remove faded flowers before pods form.

Pests and diseases

Few pests trouble rain lilies, because the alkaloids in the leaves and bulbs deter most chewing insects.

Garden snail (Cornu aspersum). Snails, and slugs with them, chew the leaves and can destroy the flowers. Hunt them at dusk after rain and use an iron-based bait if needed. Read more

Mealybugs (Pseudococcidae). White, waxy sap-suckers that cluster at leaf bases, mostly on clumps that are stressed by shade, dryness or poor drainage. Wipe them off and spray insecticidal soap. Read more

Spider mites (Tetranychidae). Worst in hot, dry weather, they turn leaves yellow or bronzed and spin fine webbing. Hose the leaves and spray insecticidal soap in the evening. Read more

Lily caterpillar (Spodoptera picta). A native pest of the amaryllis family in Queensland, New South Wales and the Northern Territory, also called the storm lily caterpillar. Pale grey caterpillars with black stripes feed in groups on the leaves, then bore down into the bulb. Pick them off by hand as soon as they are seen.

Prevention first

• After summer rain, check under the leaves for the hairy egg masses of lily caterpillar.
• Clear dead leaves and litter where snails shelter.
• Water deeply in long dry spells, which keeps mites down.
• Check new bulbs and potted clumps for mealybugs before planting.

Tips

1. Mark where the bulbs are planted, because dormant clumps vanish and are easily dug through.
2. Collect seed for new plants as the pods turn yellow and begin to split, rather than letting it scatter.
3. Where winters are hard, mulch the bed heavily, or lift the bulbs before frost and store them cool and dry until spring.

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