When to plant lily bulbs

When to plant lilies

The RHS lily guide says to plant lilies ideally in early autumn, so they can establish a good root system before winter, or in spring when bulbs are available.

The RHS bulb planting guide is more specific. It says to plant hardy summer-flowering bulbs, such as lilies, in September and October. The RHS guide to lilies in containers also prefers early autumn, and adds that bulbs can be planted until spring.

What if you plant late? The RHS says lilies planted after spring will flower later, but will go back to their usual flowering time the next year.

Plant bulbs as soon as you get them

For best results, the RHS says, plant lily bulbs immediately after buying them to prevent them drying out.

The RHS bulb planting guide makes the same point about bulbs in general. Bulbs are bought dry and dormant, and they may flower poorly if planted later than recommended or after lengthy storage. Get them in the ground or potted up as soon as you can.

Basal-rooting or stem-rooting: why depth differs

Lilies do not all root in the same way. The RHS explains that some also root from the stem above the bulb. These stem-rooting lilies go deeper than basal-rooting ones.

Plant basal-rooting lilies, or any lily when you are not sure of the type, at a depth equal to the height of the bulb. Plant slightly deeper on light, sandy soils. Plant stem-rooting lilies at a depth of roughly two and a half times the height of the bulb.

Some lilies have their own rules. The RHS plants small-bulbed species such as *L. pumilum* 8 cm deep and 10–15 cm apart, and rhizomatous lilies such as *L. pardalinum* 10 cm deep and 30 cm apart, because they spread.

Note that the RHS general bulb guide says most bulbs go in at two to three times their depth. Its lily guides are more precise, and shallower for basal-rooting lilies.

Lilium candidum: plant it shallow

*Lilium candidum* is the exception. The RHS says it has large, loose-scaled bulbs and is planted with the nose, or tip, close to the soil surface, with the bulbs 20–25 cm apart.

Soil and site

Most lilies prefer neutral to slightly acid soil, the RHS says. They do not grow well in heavy clay or in poorly drained or waterlogged soil, because the bulbs rot.

Different groups like different soils. Oriental lilies grow best in acid soil. Asiatic hybrids prefer alkaline soil. Longiflorum and trumpet hybrids will grow in most soil types.

Lilies grow in sun or partial shade, but do best where their roots are shaded and not overcrowded. They do not thrive in heavy shade. Space the bulbs 15 cm apart, or three times the bulb's diameter.

Lilies in pots

Choose a deep container with plenty of drainage holes, the RHS says. As a general guide, plant three bulbs in a 35 cm pot, in good quality peat-free multipurpose compost or peat-free John Innes No 3.

The RHS container guide gives more detail. Plant a single large bulb, 10–12 cm across, in a 20–23 cm pot, or three to four smaller bulbs, 5–8 cm across, in a 23–25 cm pot, with 5 cm between bulbs. It recommends peat-free John Innes No 3 for most lilies, and John Innes ericaceous compost for lime-haters such as *L. auratum* and *L. speciosum*. In clay pots, it puts a 5 cm layer of crocks or small stones in the base.

Lilies are heavy feeders, so the container guide adds controlled-release fertiliser granules at planting. Keep the compost moist at all times, but not wet.

Over winter, the container guide keeps pots in a cool but frost-free, airy place, such as a well-ventilated cold greenhouse or frame. It says lilies usually need cool winters to flower well, so indoors is not suitable. In southern England many lilies are fully hardy and can stay outside in larger containers all year. The RHS lily guide says the same for mild areas, and moves pots in cold areas, or of tender lilies, to a light, frost-free place such as a cool greenhouse or cold frame.

After planting: staking, watering and feeding

Tall lilies may need staking, especially in windy places. The RHS puts stakes in at planting time, because doing it later can damage the bulb.

Do not let lilies dry out or become waterlogged. Once growth begins in spring they need more water, so check pots regularly. Lilies in the ground should only need watering in very dry periods during summer, the RHS says.

For good flowering in future years, feed lilies in containers with a liquid, high-potassium fertiliser every two weeks during the growing season, until the leaves begin to yellow.

Lily beetle

The RHS container guide calls lily beetle one of the main pests of lilies. The adult is about 8 mm long, with bright red wing cases and thorax and a black head and legs. The grubs are reddish brown with black heads and hide under their own wet, black droppings.

Adults are active from late March to October, and start to appear on sunny days in late March and April. They can strip the leaves of lilies, giant lilies (*Cardiocrinum*) and fritillaries.

The RHS suggests removing beetles by hand where practical, tolerating some damage, and encouraging predators such as birds, frogs, wasps and ground beetles. Slugs and aphids may also feed on lily leaves.

After flowering

When the flowers fade, the RHS cuts the stem just below the faded flowers. Keep watering, and feeding lilies in pots, until the stems die down naturally. This helps them flower well next year. At the end of the season, cut the dead stem off at ground level.

Pots can be repotted in autumn when the foliage dies down, or the bulbs moved into the garden.

Lilies and cats

The RHS warns that all parts of lilies are poisonous to cats, and that the bulbs are a potential risk to all pets.