Ornamental · Balsaminaceae
New Guinea Impatiens
Impatiens hawkeri
Give it rich, moist soil and a little shade, and New Guinea impatiens blooms from spring straight through to frost.
Partial shade
59–81°F · 15–27°C
85–110 days
USDA 10–12
Overview
New Guinea impatiens earns its place with big, bright flowers set against deep green or bronze leaves. It came out of the islands north of Australia and grows as a tender perennial, though almost everyone treats it as a garden annual, replanting each spring. The plants stay neat and mounded, which makes them easy to tuck into beds, borders, or a pot by the door.
What sets this impatiens apart from the old bedding kind is its tougher streak. It takes more sun, the flowers and leaves run larger, and it brushes off the downy mildew that wiped out common impatiens in many gardens. The interspecific SunPatiens hybrids push that even further, holding up to full sun and real summer heat.
It asks for little beyond steady moisture. Keep the soil damp but never soggy, feed it through the season, and it blooms without a pause from spring until the first frost. Let it dry out in the heat and you'll see the leaves stipple and the flowers fade fast.
Care
The short version: partial shade and rich, well-drained soil kept evenly moist, with a balanced feed every couple of weeks and spent blooms pinched off to keep the flowers coming.
Light
Give it partial shade, especially where summers turn hot. It handles more sun than common impatiens, but bright afternoon light without enough water leaves the plants stressed and the leaves stippled.
Water
Keep the soil evenly moist at all times, never soggy and never bone dry. The more sun a plant gets, the more often it drinks, so a spot in full light or a container will need water more frequently. Good drainage is what keeps that moisture from turning into root rot.
Soil
Plant in rich, well-drained soil worked over with plenty of organic matter. The mix should hold moisture without staying wet, since these plants want damp roots but rot in standing water.
Temperature
It does best between 59°F and 81°F (15°C to 27°C) and has no tolerance for frost. Cold snaps end the plant, which is why it's grown as an annual outside the warmest zones.
Humidity
Ordinary humidity suits it fine, so there's no number to hit. Steady moisture at the roots matters far more than the air, and dry heat is what brings on spider mites.
Feeding
These are heavy feeders, especially in pots. Give a balanced liquid fertilizer every couple of weeks through the growing season to keep the blooms coming and the foliage full.
Pruning
There's no hard pruning to do. Deadhead the spent flowers to keep new ones forming, and pinch off any damaged or diseased growth as you spot it.
Size & spacing
Plants stand 6 to 20 inches (15 to 50 cm) tall and spread 12 to 24 inches (30 to 60 cm) wide, forming a tidy mound. Leave room between them so air can move and the leaves dry quickly after rain.
When to plant
New Guinea impatiens can't take frost, so timing turns on the cold. Set plants out only after the last frost has passed and nights hold above 50°F (10°C), and they bloom 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 with New Guinea impatiens traces back to water and air, either too much sitting at the roots or too little reaching the leaves in the heat. Read the early signs on the foliage and flowers and you can step in before it spreads. Match what you see below, then act while it still helps.
Wilting and collapse even though the soil is wet
When a plant wilts in soggy ground, the cause is usually root rot rather than thirst. Slip it out and check the roots, which turn brown and mushy instead of white and firm. Cut back on watering, fix the drainage or repot into a looser mix, and pull any plant that has gone too far.
Fix:
- Reduce watering frequency
- Improve soil drainage or repot
- Remove severely affected plants
Speckled, yellowing leaves with faint webbing
This is spider mites, which move in when the plant is hot and dry. Look on the leaf undersides for tiny specks and fine webbing, or tap a leaf over white paper to watch them crawl. Rinse the foliage, keep the soil moist to ease the stress, and treat 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
Cool, damp, stagnant air invites gray mold, a fungus that settles on fading blooms and spreads from there. Pick off the affected flowers and leaves, open up the planting so air can move, and water at the base instead of over the top.
Fix:
- Remove and discard affected plant parts
- Improve air circulation and spacing
- Water at the base and avoid wetting foliage
Twisted new growth, sticky leaves, or streaked blooms
Aphids and thrips go after the tender new growth and the flowers. Check the shoot tips and blooms for small insects, and watch for the silvery streaks and scarring that thrips leave behind. A hard rinse with water, a spray of insecticidal soap, and snipping out the worst growth usually settles it.
Fix:
- Rinse plants with water
- Apply insecticidal soap
- Remove heavily infested growth
Toxicity
Good news for a home with pets and kids: New Guinea impatiens is non-toxic across the board. The ASPCA lists impatiens as safe for cats, dogs, and horses, and a stray nibble won't poison the other animals around the house either. Plant it wherever you like without a second thought.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Safe for cats. A curious nibble on the leaves or flowers won't poison your cat.
Dogs None
Safe for dogs too. The ASPCA lists impatiens as non-toxic, so a chewed leaf is no cause for worry.
Horses Safe
No risk to horses. Grazing on the plant won't make them sick.
Rabbits Safe
Rabbits can browse the leaves and blooms without harm.
Livestock Safe
Cattle, goats, and sheep are fine around it, with nothing in the plant to trouble them.
Birds Safe
Backyard and pet birds face no danger from a pecked leaf or flower.
People Safe
Safe around children. The plant isn't grown for eating, but a leaf in a small mouth won't poison anyone.
Varieties
New Guinea impatiens comes in named series rather than a long list of standalone names, and a few turn up again and again. These are the ones worth knowing.
'SunPatiens'
Interspecific hybrids bred for full sun and high heat, with vigorous growth that holds up to rough weather.
'Divine'
A seed-grown series, which is unusual since most New Guinea impatiens come from cuttings instead.
'Celebration'
A cuttings-grown series carrying large flowers across a wide range of colors.
'Sonic'
A cuttings-grown series known for early, even flowering on a tidy, compact plant.
How to propagate
New Guinea impatiens is easiest to multiply from cuttings, though a handful of seed strains exist for gardeners who want to start from scratch.
Stem cuttingsEasy
Spring to summer during active growth · 2 to 4 weeks to root
Most New Guinea impatiens are grown from tip cuttings taken in spring or summer while the plant is growing, and they root in about 2 to 4 weeks. 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, can be raised this way. Sow indoors 8 to 10 weeks before the last frost, scatter the seed on the surface since it needs light, and keep it warm around 70°F to 75°F (21°C to 24°C) until it sprouts in 10 to 14 days.
Myths
New Guinea impatiens can go in full sun anywhere, like any other sun annual.
They take more sun than common impatiens, but they still need steady moisture and welcome afternoon shade where summers run hot. The interspecific SunPatiens types are the ones bred for real sun and heat tolerance.
New Guinea impatiens catch the same downy mildew that wiped out garden impatiens.
Impatiens hawkeri and the SunPatiens hybrids shrug off impatiens downy mildew, the disease that flattened the old bedding impatiens. They are the recommended stand-in for the susceptible Impatiens walleriana.