Ornamental · Balsaminaceae
New Guinea Impatiens
Impatiens hawkeri
Offer it rich, moist soil and a little shade, and New Guinea impatiens will reward you with blooms from spring all the way to frost.
Partial shade
59–81°F · 15–27°C
85–110 days
USDA 10–12
Overview
New Guinea impatiens is a lovely plant to start with, thanks to its big, bright flowers glowing against deep green or bronze leaves. It comes from the islands north of Australia and lives as a tender perennial, though most gardeners simply enjoy it as a garden annual and replant each spring, which is no trouble at all. The plants stay neat and mounded, so they settle happily into beds, borders, or a pot by the door.
What makes this impatiens a kinder choice than the old bedding type is its sturdier nature. It welcomes more sun, its flowers and leaves grow larger, and it brushes off the downy mildew that once undid common impatiens in so many gardens. The interspecific SunPatiens hybrids take that a step further and stand up to full sun and true summer heat.
It really does not ask for much beyond steady moisture, so you can grow it with confidence. Keep the soil damp but never soggy, feed it through the season, and it blooms without a pause from spring until the first frost. If it dries out in the heat you will notice the leaves stipple and the flowers fade fast, but a good drink usually brings it back.
Care
The short version: give it partial shade and rich, well-drained soil kept evenly moist, offer a balanced feed every couple of weeks, and pinch off spent blooms to keep more coming, and it will thank you.
Light
Set it in partial shade, above all where summers turn hot, and you will both be happier for it. It copes with more sun than common impatiens, yet bright afternoon light without enough water leaves the plants stressed and the leaves stippled, so keep that drink coming.
Water
Aim to keep the soil evenly moist all the time, never soggy and never bone dry, and you will find the rhythm quickly. The more sun a plant gets, the thirstier it grows, so a spot in full light or a container will want water more often. Good drainage is the quiet helper that keeps all that moisture from turning into root rot.
Soil
Plant it in rich, well-drained soil worked over with plenty of organic matter and it will feel right at home. The mix should hold moisture without staying wet, since these plants love damp roots but sulk and rot in standing water.
Temperature
It is happiest between 59°F and 81°F (15°C to 27°C) and has no tolerance for frost at all. A cold snap ends the plant, which is exactly why it is grown as an annual outside the warmest zones, so there is no shame in replanting.
Humidity
Ordinary household humidity suits it just fine, so there is no number you need to chase. Steady moisture at the roots matters far more than the air, and it is dry heat that tends to invite spider mites.
Feeding
These are heavy feeders, above all in pots, so do not be shy with them. Offer a balanced liquid fertilizer every couple of weeks through the growing season and you will keep the blooms coming and the foliage full.
Pruning
There is no daunting pruning to face here, which is a relief. Deadhead the spent flowers to keep new ones forming, and pinch off any damaged or diseased growth whenever you spot it.
Size & spacing
Plants reach 6 to 20 inches (15 to 50 cm) tall and spread 12 to 24 inches (30 to 60 cm) wide, forming a tidy little mound. Leave a bit of room between them so air can move and the leaves dry quickly after rain.
When to plant
New Guinea impatiens simply cannot take frost, so let the calendar be guided by the cold and there is no rush. Set plants out only once the last frost has passed and nights hold above 50°F (10°C), and from there 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 hiccups with New Guinea impatiens come down to water and air, either too much lingering at the roots or too little reaching the leaves in the heat, and both are fixable. Learn to read the early signs on the foliage and flowers and you can step in gently before anything spreads. Match what you notice below, then act while a little care still does the trick.
Drooping and collapse while the soil stays wet
It feels backward, but a plant drooping in wet soil is almost always suffering from root rot and not thirst, so please do not add more water. Ease it out of its pot and feel the roots, which go soft and brown once they are struggling instead of white and firm. Water less, sort out the drainage or move it into a looser mix, and let go of any plant that has slipped too far, since even that teaches you something.
Fix:
- Reduce watering frequency
- Improve soil drainage or repot
- Remove severely affected plants
Yellowing, stippled leaves showing a thin webbing
Take heart, because those pale specks usually mean spider mites, and they are easy enough to turn around once the plant is too hot and dry. Turn a leaf over and look for tiny dots and thin webbing, or tap it above a sheet of white paper and watch for movement. Rinse the leaves, keep the soil nicely moist to ease the strain, and dab insecticidal soap or horticultural oil on the undersides.
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
When the weather turns cool, damp, and still, gray mold likes to settle on tired blooms and creep outward from there, but a little tidying sets it right. Gently pick off the spotted flowers and leaves, loosen up the planting so fresh air can flow through, and water down at the base rather than over the top. You have got this.
Fix:
- Remove and discard affected plant parts
- Improve air circulation and spacing
- Water at the base and avoid wetting foliage
Curled new shoots, tacky leaves, and streaked flowers
Aphids and thrips have a soft spot for the fresh shoots and the flowers, and you can send them packing without much fuss. Peek at the shoot tips and blooms for little insects, and keep an eye out for the silvery streaks and scarring that thrips leave in their wake. A firm rinse with water, a spritz of insecticidal soap, and trimming off the worst growth usually clears things up.
Fix:
- Rinse plants with water
- Apply insecticidal soap
- Remove heavily infested growth
Toxicity
Here is a real comfort for a home with pets and kids: New Guinea impatiens is non-toxic right across the board. 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. Plant it wherever you like and enjoy it without a worry.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Rest easy with cats around, since a curious nibble on a leaf or flower will not poison them.
Dogs None
Dogs are in the clear as well, because the ASPCA lists impatiens as non-toxic, so a chewed leaf is nothing to fret over.
Horses Safe
Horses have nothing to fear here, and a mouthful of the plant will not upset them.
Rabbits Safe
Rabbits can happily browse the leaves and blooms and come to no harm.
Livestock Safe
Cattle, goats, and sheep can share the space with ease, since there is nothing in the plant to trouble them.
Birds Safe
Backyard and pet birds are perfectly fine, and a pecked leaf or flower does them no harm.
People Safe
You can feel calm with little ones nearby, and though the plant is not grown for eating, a leaf in a small mouth will not poison anyone.
Varieties
New Guinea impatiens comes to you in named series rather than a long list of standalone names, and a few show up again and again. These are the friendly faces worth knowing.
'SunPatiens'
These interspecific hybrids were developed to shine in full sun and serious heat, and their strong growth shrugs off rough weather.
'Divine'
One of the rare series you can raise from seed, a nice exception when almost all New Guinea impatiens are struck from cuttings.
'Celebration'
Grown from cuttings, this series brings big blooms in a lovely spread of colors.
'Sonic'
Grown from cuttings, this series flowers early and evenly on a neat little plant.
How to propagate
New Guinea impatiens is a joy to multiply from cuttings, and if you would rather begin from scratch, a handful of seed strains give you that option too.
Stem cuttingsEasy
Spring to summer during active growth · 2 to 4 weeks to root
Cuttings are the friendliest way in, and most New Guinea impatiens start life as tip cuttings taken in spring or summer while the plant is growing, rooting in about 2 to 4 weeks. Do keep 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 handful of seed strains, such as the Divine series, will grow this way, so it is worth a try if you like a project. Sow indoors 8 to 10 weeks before the last frost, rest the seed right on the surface since it needs light, and keep it cozy around 70°F to 75°F (21°C to 24°C) until it sprouts in 10 to 14 days.
Myths
New Guinea impatiens will happily take full sun in any spot, the way a typical sun annual does.
They do soak up more sun than common impatiens, so you have room to be generous, but they still want steady moisture and are grateful for afternoon shade where summers run hot. The interspecific SunPatiens types are the ones bred for real sun and heat tolerance.
New Guinea impatiens succumb to downy mildew just as the old garden impatiens did.
You can relax here, because Impatiens hawkeri and the SunPatiens hybrids shrug off the impatiens downy mildew that once flattened the old bedding impatiens. They are the recommended stand-in for the susceptible Impatiens walleriana.