If you love the look of impatiens but your flower beds get strong sunshine for part of the day, New Guinea impatiens (Impatiens hawkeri) will fill your yard with color. Unlike classic impatiens plants, which are shade lovers, New Guinea impatiens flowers tolerate up to half a day of sun in most parts of the country. These colorful blooms come in bright shades from lavender to orange, spanning the rainbow with a choice of bedding colors. Caring for New Guinea impatiens is no more difficult than any other flower, as long as you keep the plants well-watered throughout the hottest parts of the year.
I. Appearance and Characteristics
Impatiens hawkeri, the New Guinea impatiens, is a species of flowering plant in the family Balsaminaceae. It is native to Papua New Guinea and the Solomon Islands. It has been bred and hybridized in cultivation to produce a line of garden plants.
It was first collected in the Territory of Papua in 1884 and soon became popular as a greenhouse plant. After its discovery, fifteen other similar New Guinea taxa were collected, all of which were later determined to be forms of I. hawkeri.
Each plant will grow into a rounded mound, and if planted 18 inches (46 cm.) apart, they’ll grow to fill in the entire space in a matter of weeks. Keep the plants in the front of the bed 12 inches (31 cm.) away from the edging to keep the front branches from growing onto the lawn or sidewalk.
The thing to remember about New Guinea impatiens is that, although it will tolerate moderate amounts of sunshine, it still thrives in light shade. Flower beds on the east side of a building, which get morning sunshine and afternoon shade, are ideal locations for these plants. Fill the beds with mass plantings for the best look.
II. How to Grow and Care
Sunlight
The amount of sun exposure your New Guinea impatiens need depends on the temperature and moisture of your climate. New Guinea impatiens do best with morning sun and afternoon shade in a garden with eastern exposure. If the sun is bright and the temperatures extreme, impatiens will require more water and may not bloom as profusely.
Temperature and Humidity
Do not plant New Guinea impatiens outside until all danger of frost has passed and night temperatures are above 45 F. These flowers prefer day temperatures of 70 to 85 F and night temperatures of 55 to 65 F. They thrive in the high-humidity zones of 10, 11, and 12.
Watering
New Guinea impatiens thrive with regular waterings. Do not let them remain dry for an extended period of time or they will stop blooming and potentially die. New Guinea impatiens are not drought tolerant, yet prolonged periods of wet soil may cause their crowns to rot.1 Avoid watering them from the top, and use a drip hose instead, if possible.
Soil
New Guinea impatiens like a slightly acidic soil pH, in the range of 6.0 to 6.5, but are not terribly particular. These flowers need well-draining soil that holds moisture long enough for their roots to soak it up. New Guinea impatiens are heavy feeders, so add a good amount of organic matter to the soil during planting time. Once in the ground, give your flowers a good drink of water to help them establish themselves.
Fertilizing
Since New Guinea impatiens bloom all season long, they benefit from supplemental fertilizer. Give your flowers a dose of your favorite water-soluble food, specific for blooming flowers, every three to four weeks. You can also mix in some compost upon planting, or early and late in the season, when grown as perennials.
Pruning
New Guinea impatiens require some mid-summer pruning in order to maximize the blooms. To do so, first, deadhead the flowers by pinching the stem back to its first set of leaves. You can do this regularly throughout the season. Next, look for areas where the stems have grown leggy and are producing more foliage than blooms. Cut back your impatiens no more than 6 inches (and starting from the center stems), should they become spindly.
If your flowers look full and free of holes, there is no need to prune your impatiens at all.
Propagation
New Guinea impatiens starts are readily available at most nurseries, lending you so much variety. Still, they are easily grown from cuttings should you want to save money or if you love the specific cultivar you planted.
Here’s how to propagate New Guinea impatiens from cuttings:
- Gather garden shears, alcohol wipes, a glass, a pot, and potting soil.
- Disinfect your shears by swabbing the blades with an alcohol wipe.
- Select a hearty stem and cut 4 to 6 inches below the bloom.
- Remove the leaves from the bottom of the cutting, leaving only the top two leaves.
- Place the bottom of the cutting in a glass of water and locate it in a sunny window until it begins to root.
- Fill a pot with potting mix, water it, and allow it to drain.
- Poke a hole in the soil and place your cutting into the hole, covering up all the roots and about 1 inch of the stem.
- Place the pot in a sunny indoor location, and then harden it off by relocating it outside for several days before transplanting it into your garden.
How to Grow New Guinea Impatiens from Seed
Since New Guinea impatiens are hybrids, most varieties cannot be grown from seed, as they are either sterile or will not grow true to seed. However, there are a few cultivars that have stabilized enough so that seeds are available. These include the Divine Series, which comes in shades of white, pink, lavender, orange, and red, and the Tango, offering dramatic fluorescent orange flowers.
To grow impatiens from seed, make sure you’re in it for the long haul, as seeds will need to be started indoors about three months before your average last frost date. Fill a tray, or a 6-pack of cells, with a seed starting mix and water the soil. Plant two seeds in each cell or broadcast seeds over the tray, covering them with a dusting of soil. Mist the top, and then cover your containers with plastic and locate them in a bright spot. Remove the plastic when two sets of leaves have formed and allow the seedlings to grow for three months before transplanting them into the ground.
Potting and Repotting
New Guinea impatiens make great potted flowers that can liven up your home’s outdoor decor. To pot them, first select a container with good drainage. Next, create a false bottom in the pot by adding a thin layer of pebbles before filling the pot with soil. Take your impatiens starts out of their package and gently separate the roots at the bottom, if they seem root-bound. Relocate the starts to the container, making sure to place them to your liking, and to completely cover the roots. Water the pot and allow it to drain before placing it in a sunny location outside.
Since New Guinea impatiens grow relatively small and are mostly kept as annuals, repotting them is almost never needed.
Overwintering
Gardeners wanting to extend the life of their plants, as well as those wanting to relocate them outdoors come spring, can bring impatiens indoors during the winter. First, inspect the plant to make sure that it is free of pests and disease. Next, cut the plant back by a third, water it slightly, and relocate it to a sunny area in your home. (You may need to supplement with a plant light, if you don’t have enough natural light indoors.) Come spring, cut your plant back by half, repot it in fresh soil, water it, and harden it off by bringing it outside during the day for a few days after the last frost. Once temperatures warm, relocate the pot to a sunny spot outdoors.
Pests and Diseases
Common Pests & Plant Diseases
Like common impatiens, New Guinea impatiens can become infested with aphids and spider mites, which damage the plant by sucking its juices. Treat an infestation by first reducing the population with a spray from the garden hose. Then, spray the plant with insecticidal soap.
Necrotic spot and tomato spotted wilt can move into an inpatiens bed infested with thrips. There is no cure for these viruses, so prevention is crucial. Eliminating thrips will thwart the chances of disease moving in.
Downy mildew, botrytis blight, and verticillium wilt are fungal conditions that can affect impatiens with soggy soil. You can prevent this by maintaining a consistent watering schedule and increasing the space between plants when planting. Once these diseases move in, downy mildew can only be controlled by removing the diseased plant, while botrytis blight and verticillium wilt may respond to a fungicide.
Common Problems
Like other flowers, New Guinea impatiens can actually get sunburned and develop a condition called marginal necrosis. Brown necrosis patches on leaves are not very serious, yet they create an unsightly display. The best way to avoid this is to make sure your planting area receives ample shade.
III. Uses and Benefits
Commonly grown in containers and beds, the new guinea impatiens can be grown in borders, foundation planting, and in either mass or small group plantings. It has commonly been grown as an ornamental, free-flowering plant. A common companion of the new guinea impatiens is Azalea, however, other companion plants include Camellia, Yew, and Rhododendrons.
