Twinspur

Twinspur: how do you recognise it?

Habit

Low, bushy to trailing plant, about 25 cm tall and 35 cm wide, with thin, branching stems.

Leaves

Small, oval with a slightly toothed edge, 1–3 cm long, light green and opposite on the stem.

Flower

Flowers of 1.5–2 cm with two lips and two characteristic spurs at the back, in loose racemes at the tips of the shoots, from May to October.

Colour

Pink to salmon pink; some selections have coral-red or almost white flowers.

Roots

Fine and shallow. They like moist but well-drained soil and rot in standing water.

Flowering: May–October · Sowing: February–March · Plants: May · Pruning: April and July

Why grow it?

• Flowers for almost five months, from May to October, if you cut it back after the first flush.
• Stays low and compact: ideal for pots, window boxes, hanging baskets and edging.
• Soft pink shades that go well with blue, white and purple summer flowers.
• Attracts bees to the patio or border.
• Easy to propagate from cuttings, so you get new plants free every year.

Twinspur: where does it grow best?

• Full sun gives the richest flowering; a spot with a little shelter from the fierce afternoon sun is fine too.
• Humus-rich, free-draining soil: sandy or loamy, acid to neutral. In pots use good potting compost with some coarse sand.
• Normally moist: keep the soil evenly damp, without wet feet.
• Sheltered from strong wind and heavy rain, which can snap the fine shoots.
• Space plants 25–30 cm apart; a 30 cm pot holds three plants.

Light

Sun

Soil type

Sand or loam

Acidity

Acid or neutral

Moisture

Normal

Size

0.25 m tall, 0.35 m wide

Hardiness

Tolerates light frost (to -5 °C)

Goes well with

• Lobelia: Blue flowers next to the pink twinspur, in a pot or window box.
• Verbena: Trailing or upright verbena flowers in the same season and needs the same sunny spot.
• Pelargonium: Red or white ‘geraniums’ give a sturdy backdrop in containers.
• Bacopa: White, softly trailing and flowering from May to October, ideal in hanging baskets.
• Petunia: Same needs and a cheerful combination in pots.

Twinspur: when and how to plant it?

Plant in May.

1. Plant out in May, once the last night frost has passed.
2. Harden off home-grown or bought plants first for a week: outside by day, inside at night.
3. Dig a hole as wide as the rootball and mix a little compost into the soil. In pots, put a layer of clay pebbles at the bottom for drainage.
4. Set the plant at the same depth as in its pot, 25–30 cm from its neighbours.
5. Water in well straight away and keep the soil damp for the first weeks.

Care

Water

Water regularly so the soil never dries out completely. In pots, check daily in warm weather.

Feeding

In pots, use a liquid feed for flowering plants every two weeks; in the border every four weeks, or add organic fertiliser when planting.

Deadheading

Cut off finished flower spikes: it keeps the plant tidy and encourages new buds.

Cutting back

In July, when the first flush is over, cut the plant back by about half and feed. It then flowers until October.

Mulching

In the border a thin layer of compost or fine bark keeps the soil cool and moist.

Tip: Cut it back by half in July and feed: it then flowers until October. In August take a few cuttings as insurance for next year.

Twinspur: when to prune it?

Pruning months: April and July.

When: In July, after the first flush of flowers. A plant that has overwintered is cut back in April.

How:

• Shorten all the shoots by about half, to just above a few leaves.
• Remove dried-out or bare stems completely.
• Water and feed straight afterwards so the plant quickly regrows.
• For overwintered plants in April: cut back to about 10 cm above the ground.

Caution: Do not cut everything back at once if the plant is already very sparse: leave at least a few leaves on each stem, otherwise it is slow to regrow.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Sow indoors in February–March in a bright spot. The seed is very fine: scatter it on damp seed compost and barely cover it.

Cuttings

In August–September: take 5–8 cm cuttings from non-flowering shoots, remove the lower leaves and insert in damp compost. Overwinter them frost-free and in the light.

Twinspur: how does it get through the winter?

Hardy to −5 °C: protect in harsh winters.

• Tolerates light frost down to about −5 °C. In Belgian winters with prolonged frost or wet soil it usually dies.
• In a sheltered spot against a sunny wall, with a layer of dry leaves over it, it sometimes survives a mild winter.
• In September take a few cuttings and keep them frost-free and bright, at 5–10 °C, so you have new plants next year.
• In pots: bring them in frost-free, keep the compost barely moist and water sparingly.

Diseases and pests

• Slugs: They eat young shoots and leaves bare in spring. Hand-picking, a slug barrier or a beer trap helps.
• Aphids: Small green insects on the young tips. Rinse off with water or let ladybirds clear them.
• Root or stem rot: The plant wilts and the stems turn black at the base. It is usually caused by too much water: provide free-draining soil and drainage holes in pots.
• Exhausted after the first flush: The plant gets sparse and flowers less. Cutting back by half and feeding gives it fresh energy.

Through the year

• February: Sow under glass or on a windowsill in a bright spot.
• March: Keep sowing. Prick out seedlings.
• April: Cut back overwintered plants. Move seedlings to a bright spot.
• May: Plant out after the last frost. First flowers.
• June: Flowering. Water and feed.
• July: Cut back by half after the first flush. Then feed.
• August: Second flush of flowers. Take cuttings.
• September: Flowering. Pot up cuttings for overwintering.
• October: Last flowers. Bring plants you want to keep indoors, frost-free.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Did you know?

• The name Diascia comes from the Greek words ‘di’ (two) and ‘askos’ (little sac), after the two spurs on the flower.
• In South Africa many Diascia species are pollinated by specialised bees of the genus Rediviva, which collect oil from the spurs with their long front legs.
• The species name barberae honours Mary Barber, a nineteenth-century plant collector in South Africa.