Formosa toad lily

Formosa toad lily: how do you recognise it?

Habit

Perennial 50–70 cm tall and 40–50 cm wide, with upright to arching stems from creeping rhizomes.

Leaves

Oval to lance-shaped, up to 15 cm, glossy dark green, clasping the stem and sometimes flecked with dark spots.

Flowers

Star-shaped, 2–3 cm across, in small groups at the stem tips and in the leaf axils, from August to October.

Colour

White to pale lilac with dense purple spots.

Roots

Creeping rhizomes with short runners: the clump gets a little wider every year.

Flowering: August–October · Plants: March–May and September · Pruning: March

Why grow it?

• Flowers from August to October, just when the shady border often starts to look tired.
• Striking, orchid-like blooms spotted with purple: a real talking point.
• Glossy foliage that looks good even without flowers in a shady corner.
• Bumblebees and other insects visit the late flowers.
• Fully hardy and, despite its exotic looks, easy to grow in the garden.

Formosa toad lily: where does it grow best?

• Partial to full shade: under trees or on the north side of a wall. Full midday sun scorches the leaves.
• Humus-rich, loose, moisture-retentive soil: sand, loam or clay enriched with compost, acid to neutral.
• Normal to slightly moist soil; do not let it dry out in summer.
• Sheltered from strong wind. Allow 40–50 cm between plants.

Light

Partial shade and shade

Soil type

Loam, clay or peat

Acidity

Acid or neutral

Moisture

Normal

Size

0.7 m tall, 0.5 m wide

Hardiness

Hardy (to -20 °C)

Goes well with

• Hosta: Large leaves at the base, in the same partial shade.
• Ferns: A fresh green backdrop for a shady border.
• Japanese anemone: Also flowers late in the season, in white or pink.
• Bugbane: Tall white spikes at the same time of year.

Formosa toad lily: when and how to plant it?

Plant in March–May and September.

1. Plant between March and May or in September, when the soil is neither frozen nor waterlogged.
2. Dig a hole twice as wide as the root ball and mix in compost or leaf mould.
3. Set the plant at the same depth as in its pot, with the rhizome just below the surface.
4. Space plants 40–50 cm apart; in groups of three they look their best.
5. Water in well straight away and spread a layer of leaf-compost mulch around the plant.

Care

Water

Keep the soil evenly moist, especially in dry summers and while the buds form in August.

Feeding

A spade of compost or organic fertiliser in spring is enough.

Mulching

A layer of leaf compost or fine bark keeps the soil cool and moist and feeds the woodland-type soil.

Slugs

Young spring shoots are a slug favourite: check them often.

Dividing

Divide the clump every 4–5 years in spring if it gets too dense or bare in the centre.

Tip: Plant it beside a path or a terrace: the small spotted flowers are only really appreciated up close. Protect the young shoots from slugs in spring.

Formosa toad lily: when to prune it?

Pruning months: March.

When: In March, before the new shoots appear.

How:

• Cut last year’s dried stems down to just above the ground.
• Leave the dead stems standing over winter: they protect the rhizome from frost and shelter insects.
• Do not cut anything back after flowering: the last blooms decorate the garden until the first frosts.

Caution: It comes up late in spring: mark the clump so that you do not damage the new shoots when weeding.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Division

In March–April or in September: cut the clump with a spade into pieces with roots and runners, and replant straight away.

Seed

Seeds germinate slowly and unevenly: patience is needed, and plants flower only after 2–3 years.

Formosa toad lily: how does it get through the winter?

Hardy to −20 °C.

• Hardy to about −20 °C: no protection is needed in Flanders.
• Leave the dead stems standing until March; they protect the rhizome.
• In an exposed spot or for young plants, a layer of leaves or compost over the clump is welcome.
• In a pot: put it in a sheltered place and wrap the pot in hard frost, but never let it stand in water.

Diseases and pests

• Slugs: Holes in young shoots and leaves in April–May. Collect them in the evening with a torch and scatter coarse bark or shells around the clump.
• Drought: Brown leaf edges and falling buds in dry weather. Mulching and regular watering help.
• Sun scorch: Pale, burnt patches on the leaves in full sun. Move the plant to partial shade.
• Stem rot: Black, soft stem bases in cold, wet soil. Improve drainage with sand and compost and do not plant too deep.

Through the year

• March: Cut back dead stems. Add compost. Plant or divide.
• April: Plant. Watch for slugs.
• May: Plant. Apply mulch.
• June: Water in dry weather.
• July: Keep the soil evenly moist.
• August: Flowering begins.
• September: Full flower. Plant or divide.
• October: Last flowers.
• November: Foliage fades: leave the stems standing.
• December: Rest.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The name Tricyrtis comes from Greek and refers to the three small bulges (nectar pouches) at the base of the outer petals.
• The common name toad lily refers to the spotted flowers.
• The species name formosana means ‘from Formosa’, the old name of Taiwan, where the plant originates.