New Guinea impatiens

New Guinea impatiens: how do you recognise it?

Habit

Compact, bushy plant about 35 cm high and wide with thick, juicy stems.

Leaves

Glossy, lance-shaped, 8–15 cm, often marked bronze, purple or yellow.

Flower

Flat, 5–7 cm across, with a long, thin spur at the back; from May to October.

Colour

Pink, red, orange, lilac, white or bicolour.

Roots

Fibrous and shallow; the plant needs regular water.

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

Why grow it?

• Flowers non-stop from May to October, with blooms of 5–7 cm.
• Tolerates more sun than the ordinary busy Lizzie, as long as it gets enough water.
• Resistant to the downy mildew that affects the ordinary busy Lizzie.
• Attractively coloured foliage: bronze, purple or yellow-green, pretty even outside flowering.
• Ideal for containers, pots and hanging baskets in half shade or light sun.

New Guinea impatiens: where does it grow best?

• Half shade or sun with some shade against the fierce midday sun; it tolerates more sun than busy Lizzie, provided it gets enough water.
• Humus-rich, moisture-retentive, well-drained soil: sandy, loamy or clay, acid to neutral. In containers, good-quality potting compost.
• Average to moist: never let the soil dry out completely, but do not let it become waterlogged either.
• Space plants 30–35 cm apart; in a 25 cm container, 2–3 plants fit.

Light

Sun and partial shade

Soil type

Sand, loam or clay

Acidity

Acid or neutral

Moisture

Normal or wet

Size

0.35 m tall, 0.35 m wide

Hardiness

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

Goes well with

• Fuchsia: Hanging flowers that enjoy the same half shade and moist soil.
• Begonia: Flowers just like it in half shade on moist soil.
• Coleus: Coloured foliage in half shade, a lovely partner for the flowers.
• Ivy: Green or variegated foliage that fills the container and makes the flowers stand out.

New Guinea impatiens: when and how to plant it?

Plant in May–June.

1. Plant out in May–June, when night frost is no longer expected; it needs at least 5 °C.
2. Ease the plant out of its pot without breaking up the rootball.
3. Set it at the same depth as in the pot, in humus-rich soil or in a container with drainage holes.
4. Allow 30–35 cm between plants in a border; in containers, 2–3 plants per 25 cm pot.
5. Water well straight away and keep the soil moist.
6. In the border, mulch with a thin layer of compost or bark to keep the soil cool.

Care

Water

Daily in summer, even twice a day in hot weather in containers. In dry spells it drops its flowers.

Feeding

Every 1–2 weeks, liquid feed for flowering plants; or a slow-release feed at planting.

Pinching

Pinch back long shoots in June for bushier growth and more flowers.

Spent flowers

Faded flowers often drop by themselves; remove them for a tidier plant.

Support

Usually not needed; the juicy stems are a little brittle in strong wind.

Tip: Water daily in summer: in dry spells it drops its flowers. It tolerates more sun than the ordinary busy Lizzie, but a spot with shade against the fierce midday sun is ideal.

New Guinea impatiens: when to prune it?

Pruning months: March and June.

When: In March cut back an overwintered plant and in June shorten long shoots.

How:

• Cut overwintered plants back by about half in March, just above a leaf.
• Pinch or cut back shoots that are too long in June for bushier growth.
• Remove dead, weak or withered stems completely.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Late-summer cuttings

In August–September: take 8–10 cm tip cuttings from non-flowering shoots, remove the lower leaves and root in compost or water. They root in 2–3 weeks.

Spring cuttings

In March–April, from an overwintered plant: take tip cuttings and root them at 18–20 °C. This gives you new plants in good time for May.

New Guinea impatiens: how does it get through the winter?

Hardy to 5 °C: protect in harsh winters.

• Not hardy: it needs at least 5 °C and is grown outdoors as an annual.
• To keep it, bring it indoors in October before the first night frost and keep it bright at 12–15 °C with little water.
• You can also take cuttings in late summer and overwinter them indoors; this is easier than keeping a whole plant.

Diseases and pests

• Red spider mite: In dry, warm conditions: fine webs and yellowed, speckled leaves. Water regularly and keep the air around the plant humid.
• Aphids and whitefly: Sap-sucking insects on young shoots and under the leaves. Wash off with water or let ladybirds deal with them.
• Flower drop: Usually caused by drought or a sudden change in temperature. Water regularly and avoid drying out.
• Stem rot and grey mould: Soft, brown stems from too much water or damp weather. Water less, allow space and remove affected parts.

Through the year

• March: Cut back overwintered plants. Take cuttings.
• April: Root the cuttings. Harden plants off.
• May: Plant out after the ice saints. Water and feed.
• June: Shorten long shoots. Water daily.
• July: Full flower. Water daily and feed every 1–2 weeks.
• August: Flowering. Take cuttings for overwintering.
• September: Flowering. Root the cuttings.
• October: Bring indoors before the first frost or clear.

Did you know?

• Modern New Guinea impatiens were bred by crossing wild species from New Guinea.
• Unlike the ordinary busy Lizzie, they are not affected by the downy mildew that hit that plant hard in many countries.
• The genus Impatiens includes hundreds of species; in many of them the ripe seed capsules burst open at a touch.