If it’s rich, luscious foliage and abundant, lively blooms you are after, look no further than New Guinea impatiens.
Initially discovered on an expedition to Southeast Asia where plant hunters found them growing on stream banks high in the mountains, they were introduced to horticulture in 1978. They proved to be an almost instant hit with gardeners. Not surprising really – the masses of flowers they produce throughout the summer make them outstanding for pots, hanging baskets and in the garden. Combine this with their lush and exotic foliage that keeps them attractive beyond the summer months and you are guaranteed a winner.
New Guinea impatiens offer compact and uniform colour with good branching, and if kept free from frost will last for several years. They prefer a sheltered and partly shaded position. If grown in full sun they remain very compact, and if they are grown in deep shade they may become leggy and not flower well.
The vibrant colours of New Guinea impatiens look wonderful either mixed and matched, or grown in a mass display of single colours. Planted outside in clumps, they establish quickly to provide season long colour.
Just a few groupings will bring a touch of eye catching colour to an otherwise dull corner of the garden. After each flush of flowering, cut the plants back to promote a compact shape and they will produce even more flowers.
The New Guinea hybrids are proving resistant to the strain of downy mildew that is causing such havoc with the bedding impatiens. There is a huge range of colours to choose from – more than 20 different shades. There are lovely rich hues of reds and oranges for “hot” beds, gentle pastels to relax the eye and a pure white hybrid to add a sense of coolness on those hot summer’s days. Mixed trays are also available for those that prefer a kaleidoscope of colour.
New Guineas, especially the vibrant new hybrids, can be used extensively around patios and pool areas, along driveways and at entrances, in shady beds under trees or in borders shaded by wall, in-between shrubs and groundcovers. Window boxes, containers and the ever-popular hanging baskets make for excellent homes, especially for the compact varieties. In short, use them wherever you want to add a feel of vibrant colour.
While in the summer rainfall regions plants are available from the beginning of September, it’s best to wait for the warmth of summer before planting. Those who buy early should plant in well-protected, frost-free gardens. Even so you still run the risk of losing seedlings in late cold snaps. They prefer growing in a lightly or partially shaded position, but they will tolerate periods of full sun during the day – they do very well in morning sun positions.
The perfect spot is one with a combination of shade and sunlight, such as a veranda, patio or balcony. An eastern aspect is ideal. When planting into pots and baskets, use a container that will allow a good root system to develop. They require a good quality potting mix and regular watering. When in pots they can be brought indoors for a bit of colour and then taken outside after a week or two to allow them to recover in natural light.
As with most plants New Guinea impatiens do not like wet feet, so plant them in well drained soil. To prepare the soil, add at least one bag of compost (two bags if the soil is very sandy or has a lot of clay) and a handful of a general fertiliser to each square metre. Fork over to at least one spade’s depth (200mm) to loosen the soil thoroughly. Remove any roots from competing shrubs or groundcovers as they will compete for nutrients and moisture.
Remember that when it rains, plants under trees do not always get the benefit of the water because the trees act like an umbrella. Plants grown in sunnier positions will need more frequent watering.
Like most plants, New Guineas perform better when fed regularly. Compost alone contains very little fertiliser and so it is advisable to supplemented nutrients to ensure success. Add fertiliser to the soil at four or five week intervals, preferably 3:1:5 at the rate of one handful to every square metre. Alternatively feed weekly with a balanced water soluble fertiliser. This will virtually guarantee rave reviews all summer long.
New Guineas are “carefree” plants. Deadheading is not necessary (i.e. removing spent blooms). Occasionally in heavy shade or where the plants have been over-watered or overfed, they become leggy. Pinching back will encourage branching, a better bush shape and more flowers.