How to Grow Daylilies in Australia

Daylilies (Hemerocallis hybrids) are clump-forming perennials in the family Asphodelaceae, grown for trumpet-shaped flowers from late spring into autumn. Each flower lasts a single day, but every stem carries a run of buds. They are not true lilies (Lilium), which have a guide of their own. Water-storing roots suit them to hot Australian summers, and the common mistake is burying the crown too deep.

Three mistakes that matter

1. Burying the crown. A crown set deep in the soil makes leaves but few flowers, and the clump slowly declines. Plant with the crown at soil level or just below it, as set out under Planting Crowns.
2. Choosing the wrong foliage type for the zone. Dormant daylilies need a cold winter, and in warm districts they can grow and flower poorly. Grow evergreen or semi-evergreen types in the tropics and subtropics, and keep dormant types for cooler gardens.
3. Planting into soggy ground. Roots that sit in water for long spells weaken, and in warm weather the crown can turn soft, foul-smelling and rotten. Choose a free-draining spot or a raised bed, never a hollow where water pools after rain.

When to plant

Plant bare-root divisions in mild weather, into soil that is moist but not waterlogged. Autumn suits most gardens, with Anzac Day a handy marker in the south, because roots settle before spring growth. Allow six to eight weeks for rooting before hard frost. A second window opens in late winter and early spring, before the heat.

Avoid planting through a heatwave.

Site, soil and setup

Daylilies take most soils, from sand to heavy clay, provided water drains away from their shallow roots. Light matters more: full sun brings the most flowers. The flowers turn to face the sun, so plant where you will see their faces.

A clump stays put for years, so rotation does not apply; refresh the soil with compost when you divide. Where water lies after rain, read waterlogged soil first.

Choosing a type for your zone

Foliage type decides where a daylily does best. Dormant types die back after frost and regrow in spring. Evergreen types keep their leaves, and semi-evergreen types vary with the climate.

Container growing

Compact types such as 'Booby Ruby', 'Bettylen' and 'Daria' grow well in pots. Use one at least 40 cm wide, about 30 L, filled with premium potting mix.

• Watering. Pots dry out fast, so water daily in hot weather. See watering pots in summer.
• Feeding. Mix a controlled release fertiliser for containers into the potting mix at planting, and scratch in a fresh dose each spring. Add seaweed solution at 30 mL per 9 L once a fortnight while buds form.
• Position. Full sun. In the tropics, move the pot out of wet-season rain.
• Repotting. Divide and repot every few years, once roots fill the pot and flowering falls away.

Planting Crowns

Daylilies are grown from divisions, because seed of a hybrid daylily does not come true to its parent.

Before planting

A bare-root division is a dormant crown with tuberous (fleshy, food-storing) roots and a short fan of trimmed leaves. It can look dry on arrival, which is normal. A soft or foul-smelling crown has rotted, so tell the seller straight away. Plant it soon, after soaking the roots in water for a few hours and snipping off any damaged ones.

Planting a bare-root division

1. Dig a hole about twice as wide as the spread of the roots, in soil prepared as under Site, soil and setup.
2. Build a cone of soil in the centre, sit the crown on top and spread the roots down its sides.
3. Set the crown, the point where leaves meet roots, at soil level or under no more than 2.5 cm of soil.
4. Fill in, firm gently and water in with seaweed solution at 30 mL per 9 L.
5. Space plants 40 to 60 cm apart, closer for compact types and wider for large ones.
6. Mulch with 5 cm of compost or leaf mulch, kept clear of the crown itself.

Settling in

Keep the soil evenly moist, not wet, for six to eight weeks. New leaves from the centre of the fan show that roots have formed. A division can take one to two growing seasons to flower fully, so a light first summer is normal.

Care by growth stage

Steady water while scapes (the flower stems) and buds form decides how many flowers a clump gives. Feed lightly, because too much nitrogen gives leaves at the expense of flowers.

If growth stalls in poor soil, a light dose of all-purpose controlled release granular (NPK around 14-5-10) in early spring can help. Water the soil, not the plant: drops spot flowers and wet leaves favour rust.

Division and Maintenance

Daylilies need little beyond tidying, but an old clump loses vigour. Divide it every three to five years, or once the centre flowers less than the edges.

• Pick off spent flowers every day or two, because they turn to mush and can dry onto the bud below and stop it opening.
• Cut each scape at its base once its last bud has flowered, so the plant does not spend energy on seed pods.
• In late winter, pull away dead leaves and bin them, because they can harbour rust and pests.
• Divide after the main flowering, or in late winter in the subtropics, so new roots form before the heat.

Keep the fans shaded and damp until replanted. The method suits many perennials, as in dividing perennials.

1. Lift the whole clump with a garden fork and shake or hose off the soil.
2. Cut or pull it apart from the centre into fans, each with its own crown and roots.
3. Remove any scape, then cut the leaves back to a fan about 15 cm long to reduce water loss.
4. Trim old and broken roots, then replant each fan as under Planting Crowns.

Companion planting

Sun on the leaves comes first, so pair daylilies with low plants or ones that flower at another time.

Grows well with

• Daffodils and jonquils, which flower first; the growing daylily leaves then hide their yellowing foliage.
• Ornamental grasses and silver-leaved perennials, which set off dark flowers such as 'Black Stockings'.
• Low, open shrubs that frame a bed without shading the clumps.

Keep apart

• Trees and large shrubs, whose shade and roots cut flowering.
• Golden valerian (Patrinia), the alternate host of daylily rust.
• Plants that need frequent overhead watering, because wet daylily leaves favour rust.

Harvesting Blooms

For a vase, cut a whole scape when its first bud shows colour and several plump buds sit behind it.

• Cut in the cool of early morning, at the base of the scape.
• Pick off each flower as it fades, so the next bud has room to open.
• Change the vase water every two days.
• Stand the vase where cats cannot reach it.

A daylily flower cannot be stored, so pick by the stem. In a vase, the buds on one scape can open in turn for a week or more.

Common problems

Plenty of leaves, few flowers. Fewer than six hours of sun or a crown planted too deep is the usual cause (see Three mistakes that matter).

Bare, flowerless centre. The clump is crowded and due for dividing, as under Division and Maintenance.

Buds that wither unopened. Thrips feeding inside the buds, or dry soil while scapes form, can stop buds opening; keep up weekly soaks through flowering.

Tall stems that snap. Too much nitrogen pushes scapes tall and weak, so feed only as under Care by growth stage.

Pests and diseases

Daylilies are rarely bothered by pests, but these five are worth watching for.

Daylily rust (Puccinia hemerocallidis). First found in Australia in south-east Queensland, it raises small yellow spots on the leaves with orange, powdery pustules mostly underneath. Cut off and bin affected leaves, and replace a badly affected clump with a more resistant variety.

Hemerocallis aphid (Myzus hemerocallis). Recorded on daylilies in Australia, it sucks sap from young leaves and buds in cool spring weather, leaving distorted growth and sticky honeydew. Spray insecticidal soap and let ladybirds and lacewings do the rest. Read more

Thrips (Thysanoptera). These tiny insects hide in buds and leaf bases, leaving white streaks on petals and buds that die without opening. Spray insecticidal soap into the buds and leaf bases in the evening, to spare bees, and repeat as the label directs. Read more

Two-spotted mite (Tetranychus urticae). In hot, dry weather it stipples leaves yellow, starting low in the clump, and spins fine webbing. Spray insecticidal soap early, and avoid broad insecticides, which kill the predators that keep mites down. Read more

Garden snail (Cornu aspersum). Snails, and slugs with them, chew ragged notches in tender new growth, worst in early spring. Clear the dead leaves and old scapes they shelter in, and use an iron-based bait if needed. Read more

Prevention first

• Check the undersides of leaves for orange pustules before planting any new division.
• Keep the spacing under Planting Crowns, so leaves dry quickly after rain.
• Keep the bed free of weeds, which harbour thrips.
• Check buds and young leaves weekly from early spring, when aphids and thrips build up.

Tips

1. Grow early, mid and late flowering varieties together to stretch the display across the warm months.
2. Plant dark reds and purples where they get afternoon shade, and pale colours in full sun.
3. Label each clump at planting, because dormant types vanish in winter and names are easily lost.
4. Open daylily flowers draw insects, so a few clumps earn a place in a pollinator planting.

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