June 2003

Culture Tips for Infinity New Guinea Impatiens By Nicole Jackson

New Guinea impatiens burst onto the gardening scene 30 yearsago and already have become etched in the gardener’s mind as the perfect shadeplants.

Now comes Infinity, a new series from renowned breederLudwig Kientzler. The Kientzler name has been synonymous with quality andinnovation since 1904. Ludwig Kientzler carefully bred Infinity to be growerfriendly with consistent vigorous habit and finishing times across the seriesand also to have the features consumers demand: large flowers, dark green topurple foliage and a variety of color choices.

More vigorous than most other series, these New Guineas fillcontainers and baskets quickly. Their vigorous habit makes them an easy choicefor 10-inch, 12-inch or even larger baskets, plus their production performancein 4-inch, 5-inch or even gallon pots is exceptional. Although when usingsmaller pots, it is best to space the pots to allow the best developmentpossible. Rigorous trials and selectionprocess under outdoor conditions have shown this series to be especiallydurable and attractive, even in the heat and rain. For consumers, Infinity isgreat in shade combination planters, pots, hanging baskets and in thelandscape.

There are 17 colors in the series — Blushing Lilac,Cherry Red (shown above left), Dark Pink, Dark Salmon Glow, Lavender, LightSalmon, Light Purple, Lilac, Orange, Orange Frost, Pink, Pink Frost, Pink Kiss,Red, Salmon, Scarlet (center) and White (right) — all new for 2004.

Growing on

Infinity performs best in fast draining medium withsufficient peat moss and perlite. Plant 3-5 liners per 8- to 10-inch pot andone liner per 4- to 6-inch pot. Keep pH at 5.8-6.2 and EC at 0.5-0.7. LightLevels should be moderate to high. Maximum light intensity is recommended inearly to mid-spring for optimal growth. Light shade should be used in latespring, but light intensity should be between 3,000-5,000 foot-candles. Highlight promotes growth, increases leaf variegation and intensifies leaf color ofthe cultivars with dark leaves.

Normal day temperatures should be 65-75° F and normalnight temperatures 60-70° F. Night temperatures above 70° F may cause adelay in flowering.

New Guinea impatiens transpire a large amount of water, butdo not respond well to continually water-logged medium. After transplant-ing,it is best to keep the medium just moist, as over watering during this timewill cause problems. Although they will tolerate slight wilting, leaf andflower burn will occur if the plants are over stressed. We recommend avoidingwilting but allowing plants to dry between watering.

Finishing time for 8- to 10-inch pots is 11-13 weeks and 8-9weeks for 4- to 6-inch pots.

Fertilizers, Pests and Diseases

Infinities prefer 100-100-100 ppm N-P-K for the first fourweeks or when the roots have hit the side of the pots. Then 200-100-200 ppmN-P-K for the rest of the crop cycle. Soluble salts can cause severe root damageabove 2.0 millimhos during production. New Guinea impatiens need only moderatelevels of micro-nutrients. Excess minor nutrients will cause dieback of thegrowing tip, leaf margin necrosis and total plant collapse. Poor nutrition mayresult in yellowing of leaves, leaf drop and small flowers.

As for pests, watch for thrips, spider mites and cyclamenmites.

Maintain moderate humidity levels but good air movement toprevent Botrytis and Myrothecium. Watering plants early in the day and ventingin the afternoon will help control Botrytis. New Guinea impatiens may becomeinfected with root rot caused by Rhizoctonia, Pythium and Phytophthora. Thiscan occur especially when plants are over-watered. Drench with a broad-spectrumfungicide at liner planting to reduce these disease problems. ImpatiensNecrotic Spot Virus (INSV) can be a problem; however, this virus is easilycontained if thrips, the necessary vectoring agent, are controlled.