Egyptian starcluster

Egyptian starcluster: how do you recognise it?

Habit

Compact, branching subshrub 30–40 cm high and 30 cm wide; grown here as an annual.

Leaves

Opposite, lance-shaped to oval, 5–10 cm long, fresh green, slightly hairy, with clear veins.

Flowers

Round heads of small, five-pointed stars with a long tube, from June to October.

Colour

Red, pink, lilac and white, often with a paler eye.

Roots

Fine and fibrous; it likes moist but well-drained soil.

Flowering: June–October · Plants: May–June · Pruning: March

Why grow it?

• Flowers non-stop from June to October, even in hot summers.
• A real butterfly magnet: the nectar-rich flowers are visited busily by butterflies and bees.
• Compact and neat (about 40 cm), ideal for pots, window boxes and the front of a sunny border.
• Pretty as a cut flower in small posies, with the rich colours of the flower heads.
• Easy to propagate from cuttings, so you can have new plants every year.

Egyptian starcluster: where does it grow best?

• Full sun and warmth; in light partial shade it also flowers, but less abundantly.
• Free-draining soil rich in humus: sand or loam, acid to neutral. In a pot, good-quality compost works well.
• Evenly moist: the root ball must not dry out, but must not sit in water either.
• Sheltered and warm, for example against a sunny wall; it dislikes cold or wet nights.
• Plant 25–30 cm apart, or three plants in a 30 cm pot.

Light

Sun

Soil type

Sand or loam

Acidity

Acid or neutral

Moisture

Normal

Size

0.4 m tall, 0.3 m wide

Hardiness

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

Goes well with

• Zinnia: The same sun and warmth, with bold colours that complement the little stars of pentas.
• Sage: Ornamental sage with blue spikes looks lovely next to red or pink pentas and also attracts bees.
• Lantana: Flowers in the same warm shades and needs the same sunny spot.
• Ornamental grasses: Soft plumes and fine stems make the bright heads stand out.

Egyptian starcluster: when and how to plant it?

Plant in May–June.

1. Plant only from mid-May or June, when nights are no longer cold; below about 5 °C it suffers.
2. First let the plants get used to the outdoors by day for a week and bring them in at night.
3. Dig a hole slightly larger than the root ball, or fill a pot with good compost; make sure there are drainage holes.
4. Set the plant at the same depth as in the nursery pot and firm the soil lightly.
5. Water generously straight away and keep the soil evenly moist for the first few weeks.
6. In a border, mulch with a thin layer of compost to keep the soil moist.

Care

Water

Regular and even, especially in pots in warm weather. Water at the base; the root ball must never dry out completely.

Feeding

From May to September give a flowering-plant feed in the water every two weeks for continuous flowering.

Faded flowers

Cut faded heads off with their stalk. This encourages new flowers and keeps the plant neat.

Pinching

Pinch out the tips of young plants after planting for a bushy, free-flowering shape.

Repotting

Put overwintered plants in fresh compost and a slightly larger pot in spring.

Tip: Put pentas in a warm, sunny spot and never let the soil dry out completely. Pinch out young plants and cut faded heads off, and it will flower until the first cold nights.

Egyptian starcluster: when to prune it?

Pruning months: March.

When: In March for overwintered plants; during the season, pinch out tips and cut off faded heads.

How:

• Pinch out the tips of the shoots on young plants after planting so they branch.
• Cut faded heads back to just above the next pair of leaves.
• Shorten overwintered plants by a third to a half in March and remove weak shoots.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Softwood cuttings (late summer)

In August–September: take cuttings of 8–10 cm from non-flowering tips, remove the lower leaves and insert them in moist cutting compost. Keep them bright and warm; they usually root within a few weeks.

Softwood cuttings (spring)

In March–April: use the shoots from cutting back overwintered plants and treat them the same way. They flower already in summer.

Egyptian starcluster: how does it get through the winter?

Hardy to 5 °C: protect in harsh winters.

• Not hardy: it does not tolerate frost and suffers already below about 5 °C. Bring it indoors in October, before the first cold nights.
• Overwinter in a bright, frost-free place, preferably at 10–15 °C, for example a cool conservatory or a bright room. Water sparingly and stop feeding.
• Short of space? Take a few cuttings in August–September and overwinter those on a windowsill.
• Cut back in March and repot in fresh compost; put back outside after mid-May.

Diseases and pests

• Spider mite: Fine webs and yellowish speckles on the leaves in dry, warm air. Mist the leaves now and then with water and remove affected parts.
• Aphids and whitefly: Sticky leaves and small insects on young shoots. Rinse off with water, use a mild soap solution and let natural enemies such as ladybirds help.
• Yellow leaves with green veins: Iron deficiency (chlorosis) in too chalky soil or with water that is too cold. Use ericaceous compost, possibly an iron feed, and do not water with cold water.
• Root rot: Limp plant and brown roots in wet soil. Ensure good drainage and water less; discard the plant if rot is severe.

Through the year

• March: Cut back overwintered plants and repot.
• April: Take cuttings and harden off by day.
• May: Put outside after mid-May. Pinch out the tips.
• June: First flowers. Feed every two weeks.
• July: Full flower. Water and cut off faded heads.
• August: Flowering. Take cuttings for overwintering.
• September: Flowering. Ease off feeding.
• October: Last flowers. Bring indoors before the cold nights.
• November: Winter rest: bright, frost-free and little water.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Butterflies

Nectar for butterflies.

Did you know?

• The name Pentas comes from the Greek pente (five), because each flower has five lobes.
• Despite the English name ‘Egyptian starcluster’, the plant does not come from Egypt but from tropical Africa and the Arabian Peninsula.
• Pentas belongs to the Rubiaceae, the family that also includes the coffee plant.