Wishbone flower

Wishbone flower: how do you recognise it?

Habit

Compact, cushion-shaped annual 20–30 cm tall and wide, with branching, square stems.

Leaves

Oval to lance-shaped, 3–5 cm, with a toothed edge; fresh green and opposite.

Flower

Trumpet-shaped, two-lipped flowers about 3 cm across, from June to September.

Colour

Blue, violet, pink, white or wine-red; the lower lip often has a yellow blotch.

Roots

Fine and shallow: the plant dries out quickly, so keep the soil evenly moist.

Flowering: June–September · Sowing: February–March · Plants: May–June · Pruning: July

Why grow it?

• Flowers from June to September in partial shade and shade, where few summer plants flower freely.
• Compact and dense: a lovely filler for pots, boxes and hanging baskets.
• Many colours: blue, violet, pink, white or wine-red, often with a yellow throat.
• Little work: a bit of water and the occasional feed is enough.
• A fresh companion for hostas and ferns in a shady border.

Wishbone flower: where does it grow best?

• Partial shade or shade; in hot midday sun the leaves scorch and flowering fades.
• Humus-rich, moisture-retentive but well-drained soil: sand, loam or clay, acid to neutral.
• Sheltered and warm: it is frost-tender and does not grow well below about 5 °C.
• Space plants 15–20 cm apart; put 3–4 plants in a 25–30 cm pot.

Light

Partial shade and shade

Soil type

Sand, loam or clay

Acidity

Acid or neutral

Moisture

Normal or wet

Size

0.25 m tall, 0.25 m wide

Hardiness

Frost tender: plant out after the last frost (mid-May)

Goes well with

• Hosta: Large leaves give calm beside the small wishbone flowers in the same shade.
• Begonia: Same position and a different flower shape for a varied summer container.
• Coleus: Coloured leaves as a backdrop for the blue and purple flowers.
• Trailing lobelia: A second blue flower for partial shade that spills over the pot edge.
• Ferns: A fresh, green underplanting for a shady border.

Wishbone flower: when and how to plant it?

Plant in May–June.

1. Sow indoors in February–March. The seed is dust-fine: scatter it on moist seed compost and do not cover it, as it germinates in light at 20–24 °C.
2. Prick out the seedlings once they have two true leaves and grow them on in a bright spot at 15–18 °C.
3. Harden the plants off from early May and plant them out from mid-May to June, when frost is no longer a risk.
4. Dig a hole as deep as the pot, mix in some compost and space the plants 15–20 cm apart.
5. Water in well and pinch out the tips above the third or fourth pair of leaves for bushy growth.
6. A thin layer of compost or fine bark keeps the soil cool and moist.

Care

Water

Keep the soil lightly moist at all times, in pots too. In dry spells leaves and flowers droop quickly. Water at the base, not over the foliage.

Feeding

From June to August, add a liquid feed for flowering plants to the water every two weeks.

Pinching out

Pinch out young plants so they branch; you get more side shoots and so more flowers.

Deadheading

Usually not needed: the flowers drop by themselves. Do remove dried stems and leaves.

Pots and boxes

Use potting compost and check daily in warm weather that it is still moist.

Tip: Keep the soil evenly moist and shield it from hot midday sun. Pinch out young plants and cut back long shoots in July: it then flowers until the first frost.

Wishbone flower: when to prune it?

Pruning months: July.

When: It is not really pruned: pinch out young plants in May and cut back long, bare shoots in July.

How:

• In May, pinch out the tip of young plants above the third or fourth pair of leaves.
• In July, cut long, bare shoots back by a third; they regrow within a few weeks and flower again.
• Remove dried or damaged stems and leaves.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

In February–March indoors. Scatter the dust-fine seed on the surface, press it in lightly and do not cover it. Keep moist at 20–24 °C; it germinates in 2–3 weeks.

Cuttings

In August–September take 5–8 cm cuttings of non-flowering shoots; they root easily in water or moist potting compost. Overwinter them in a bright, frost-free place.

Wishbone flower: how does it get through the winter?

Hardy to 5 °C: protect in harsh winters.

• An annual and frost-tender: the first night frost finishes it. Clear the plants away then.
• To keep it, take cuttings in late summer and overwinter them in a bright place at 10–15 °C.
• You can collect ripe seed in late summer and keep it dry until next spring.

Diseases and pests

• Slugs: Young plants are eaten most. Use iron phosphate pellets or collect the slugs in the evening with a torch.
• Spider mite: Fine yellow stippling and webbing on the leaves in warm, dry weather. Mist the plants, water more and rinse with water.
• Aphids: Sticky, curled shoots. Wipe them off or rinse with water; ladybirds help.
• Fungal rots: Too much moisture rots stem bases or gives grey mould on the flowers. Water at the base and leave air between plants.
• Scorched leaves: Brown, dry edges after strong midday sun. Move it to a sheltered spot with only morning or evening sun.

Through the year

• February: Sow indoors in a bright place at 20–24 °C.
• March: Finish sowing. Prick out seedlings.
• April: Grow plants on in a bright spot at 15–18 °C.
• May: Harden off. Plant outside from mid-May.
• June: First flowers. Water and feed.
• July: Full flower. Cut back long shoots. Feed.
• August: Water in dry weather. Take cuttings.
• September: Last flowers. Collect seed.
• October: Clear the plants after the first frost.

Did you know?

• The name wishbone flower refers to the two stamens in the heart of the flower, which together form a V shape.
• The genus Torenia is named after Olof Torén, a Swedish clergyman and naturalist of the 18th century.
• The yellow blotch in the throat of the flower works as a nectar guide: a signpost for visiting insects.