Ornamental · Balsaminaceae
New Guinea Impatiens
Impatiens hawkeri
Root it in loamy, moisture-rich soil and cool shade, and New Guinea impatiens unfurls blooms from spring on through frost.
Partial shade
59–81°F · 15–27°C
85–110 days
USDA 10–12
Overview
New Guinea impatiens is built around big, bright flowers, broad flat blooms that sit open against leaves colored deep green or a burnished bronze. The plant traces back to the islands north of Australia and grows as a tender perennial, though most gardeners keep it as a garden annual and set out fresh plants each spring. The stems build into a low, rounded mound, neat and even from every side.
Set beside the old bedding impatiens, this one reads bigger and bolder in the hand. The flowers and leaves both run larger, the foliage carries that green-to-bronze depth, and the plant shrugs off the downy mildew that stripped common impatiens across so many gardens. The interspecific SunPatiens hybrids push the same heavy flowering through full sun and real summer heat.
The blooms open across a wide range of colors and keep coming without a break from spring to the first frost, as long as steady moisture reaches the roots. Damp but never soggy soil and a feed through the season hold that display. Let it dry in the heat and a fine stippling dulls the leaves while the flowers fade fast.
Care
The short version: partial shade over rich, well-drained soil kept evenly moist, a balanced feed every couple of weeks, and spent blooms pinched from the mound to keep fresh flowers opening.
Light
The plant wants partial shade, above all where summers turn hot. The broad leaves take more sun than common impatiens, but a bright afternoon without enough water leaves them slack and stippled, the color going flat where the surface dries.
Water
The soil should stay evenly moist throughout, never soggy and never bone dry. The more sun striking those open blooms, the faster the plant drinks, so a spot in full light or a container empties quicker. Good drainage keeps that moisture from souring into root rot.
Soil
The roots want rich, well-drained soil worked through with plenty of organic matter. The mix should hold moisture yet let the excess drain, since the fine roots crave damp but rot in standing water.
Temperature
The soft foliage does best between 59°F and 81°F (15°C to 27°C) and carries no frost hardiness. A cold snap blackens the stems and ends the plant, which is why it grows as an annual outside the warmest zones.
Humidity
Ordinary humidity suits it, so there is no figure to reach. Moisture at the roots matters far more to the leaves than the air around them, and it is dry heat that pulls in spider mites and their fine webbing.
Feeding
These are heavy feeders, above all in pots. A balanced liquid fertilizer every couple of weeks through the growing season keeps the blooms broad and open and the foliage thick and full.
Pruning
The mound needs no hard pruning. Deadheading the spent flowers pulls the browning blooms off and keeps fresh buds opening, and any damaged or diseased growth comes away as it shows.
Size & spacing
The plant stands 6 to 20 inches (15 to 50 cm) tall and spreads 12 to 24 inches (30 to 60 cm) wide into a rounded mound. A little gap between mounds lets air pass and dries the leaf surfaces after rain.
When to plant
New Guinea impatiens holds no frost hardiness in its soft stems and leaves, so timing turns on the cold. Set plants out only after the last frost passes and nights hold above 50°F (10°C), and the blooms open from spring right through to the first frost in fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: 8 to 10 weeks before last spring frost (seed strains only)
- Plant: After last frost when soil and night temperatures stay above 50°F (10°C)
- Harvest: Spring through fall until frost
Hardiness
USDA hardiness zones: 10–12
Temperature: down to -1°C
Troubleshooting
Most trouble on New Guinea impatiens writes itself onto the leaves and flowers first, from a change in leaf color to a mark on the petals, and the cause almost always traces to water or air. A close look at the foliage and blooms catches it early. Match what you see below, then act while the damage is still small.
Limp, collapsing stems above sodden soil
Leaves that hang limp and yellow while the soil sits wet are the face of root rot, not thirst. Lift the plant and the roots tell the story, gone soft and brown and slippery instead of the firm white of healthy ones. Cut the watering back, loosen or drain the mix, and lift out any plant whose roots have turned to mush.
Fix:
- Reduce watering frequency
- Improve soil drainage or repot
- Remove severely affected plants
Peppered yellow leaves under gossamer webbing
A fine sandy stippling that dulls the leaf color and a thin, silky webbing across the surface are the marks of spider mites, which crowd in when the plant is hot and dry. Turn a leaf and the underside carries tiny moving specks tangled in the webbing, or tap it over white paper and watch the dots scatter. Rinse the foliage, keep the soil damp to ease the strain, and coat the undersides with insecticidal soap or horticultural oil.
Fix:
- Rinse foliage with water
- Keep soil moist and reduce heat/drought stress
- Apply insecticidal soap or horticultural oil to leaf undersides
Fuzzy gray mold on flowers and leaves
A soft, grayish-brown fuzz creeping over spent petals and leaves is gray mold, a fungus that grips the fading blooms first when the air turns cool, damp, and still. Strip off the furred flowers and leaves before the fuzz spreads onto sound tissue. Open the planting so air threads through, and lay the water at the base so the petals stay dry.
Fix:
- Remove and discard affected plant parts
- Improve air circulation and spacing
- Water at the base and avoid wetting foliage
Puckered new growth, glossy sticky leaves, silver-streaked blooms
Curled, twisted shoot tips, a sticky sheen on the leaves, and pale silvery streaks scored across the petals give away aphids and thrips, which crowd onto the softest new growth and the flowers. Look close at the tips and blooms for the small insects, and read the silvery scarring the thrips scratch into the color. A hard rinse, a coat of insecticidal soap, and cutting away the worst-hit growth clears them.
Fix:
- Rinse plants with water
- Apply insecticidal soap
- Remove heavily infested growth
Toxicity
For a home with pets and children, the plant is easy company: New Guinea impatiens is non-toxic through leaf, stem, and flower. The ASPCA lists impatiens as safe for cats, dogs, and horses, and a stray nibble will not poison the other animals around the house either. It can grow wherever curious mouths reach, with nothing to fear.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
The leaves and flowers are safe for cats, so a curious nibble of either will not poison them.
Dogs None
Dogs are safe as well, since the ASPCA lists impatiens as non-toxic, so a chewed leaf is harmless.
Horses Safe
Horses take no harm from the foliage, and a mouthful of the leaves will not make them sick.
Rabbits Safe
Rabbits can browse the soft leaves and open blooms with no harm.
Livestock Safe
Cattle, goats, and sheep meet nothing harmful in the leaves or stems of the plant.
Birds Safe
Backyard and pet birds are safe, and a pecked leaf or petal does them no harm.
People Safe
The plant is safe around children; it is not grown for eating, but a leaf reaching a small mouth will not poison anyone.
Varieties
New Guinea impatiens reaches gardeners as named series rather than a long list of standalone names, and a few turn up again and again. These are the ones worth knowing by sight.
'SunPatiens'
Interspecific hybrids toughened for high heat and blazing sun, their stems pushing vigorous, weather-hardy growth through rough spells.
'Divine'
A series started from seed, unlike the cuttings that give rise to nearly every other New Guinea impatiens.
'Celebration'
A cuttings series whose oversized blooms open in a wide spectrum of hues.
'Sonic'
A cuttings series that flushes early, uniform blossoms across a dense, compact mound.
How to propagate
New Guinea impatiens roots easily from cuttings of its soft stems, while a small number of seed strains give another route for growers who want to start from scratch.
Stem cuttingsEasy
Spring to summer during active growth · 2 to 4 weeks to root
A short length of soft stem tip, cut in spring or summer while the plant is pushing new growth, is how most New Guinea impatiens begin, and pale new roots break from the cut end in about 2 to 4 weeks. Bear in mind that many named cultivars are patented, so propagating them at home may not be legal.
SeedModerate
Indoors 8 to 10 weeks before last frost · 10 to 14 days to germinate
Only a few seed strains, such as the Divine series, come true from seed. Sow indoors 8 to 10 weeks before the last frost, press the fine seed onto the surface since it needs light to break, and hold it warm around 70°F to 75°F (21°C to 24°C) until the green sprouts show in 10 to 14 days.
Myths
New Guinea impatiens blooms in full sun in any bed, just as an everyday sun annual does.
The broad leaves and open petals take more sun than common impatiens, but they still draw on steady moisture and hold their color better under afternoon shade where summers run hot. The interspecific SunPatiens types are the ones bred for real sun and heat tolerance.
New Guinea impatiens are struck by downy mildew, the scourge that wiped garden beds of impatiens.
The thick leaves of Impatiens hawkeri and the SunPatiens hybrids stay clean of the impatiens downy mildew that once stripped the old bedding impatiens bare. They are the recommended stand-in for the susceptible Impatiens walleriana.