Growing Tips for the Soiree Kawaii Catharansus Series
May 7, 2019 
Lorentina McKoy, Suntory Flowers
Looking for heat-loving annuals? Catharanthus Soiree Kawaii from Suntory Flowers thrive in the harshest Southern conditions, while also looking great all summer up North. The word “kawaii” means cute in Japanese, describing the flower size and shape. Think of these varieties as Vinca’s cute little sister. Advantages include a compact habit with superior branching and more flowers on shorter internodes in small pots. No pinching is needed. Attractive glossy foliage complements the profusion of blooms, creating tidy mounds of color.
Soiree Kawaii should not be started too early in the season says Lorentina McKoy, National Sales and Product Rep for Suntory Flowers. If temperatures are cool, it will be a struggle. Northern growers should produce as a summer crop, transplanting no sooner than week 12. Winter is too soon for the South. Transplanting prior to week 7 in the Southern climates is a struggle to get them going, but once the weather breaks, so do they.
Make sure liners are mature before transplanting into pots; wait until the roots spread outside to the edge in the liner stage. Keep in mind that roots can develop in 14 to 21 days with bottom heating, but a mature liner takes 40 to 45 days. Six weeks from stick to transplant is ideal. For best results, keep Soiree Kawaii plants warm and dry in a sunny environment. Most importantly, keep soil temperatures warm — above 70°F during the day and above 65°F at night. Soiree Kawaii plants will stop growing if temperatures dip below 53°F for consecutive days, and then they start to rot. It is best to wait for warmer temperatures to start production.
Watch out for whiteflies, aphids, western flower thrips, and red spider mites when scouting for pests. Diseases to monitor include Botrytis, Thielaviopsis, Corynespora, Phythophthora, Pythium, and Rhizoctonia. Using the same preventative rotation that is used for seed Vinca does well in practice. Heritage, Subdue, and Medallion all work well, although Soiree Kawaii has not shown signs of disease as often as others in its genus.
McKoy’s Recommendations for Growing ‘Soiree Kawaii’ Successfully
• Fertilizer: 200 to 250 ppm; keep pH 5.4 to 6.1 and EC 1.0 to 2.0
• Propagation: Stick cuttings in a substrate with pH of 5.4 to 5.8. Maintain substrate temperature of 78°F. Constant soil temperature is very important in the early stages of rooting.
• Plant growth regulators: Optional. B-9 can be applied at 2,500 to 5,000 ppm.
• Lighting: Begin with 500 to 1,000 footcandles during rooting. Increase light intensity to 1,000 to 2,000 footcandles as roots develop. Maintain high light levels after toning rooted cuttings.
• Pinching: Optional. Always ensure you have at least two nodes, especially in cool periods. Growers can trim any stretched stems two weeks before shipping and still have a nice retail presentation.
• Growing media: Well-drained peat lite mix
• Irrigation: Don’t overwater. Allow substrate to dry out between watering. Water plants prior to wilting.
• Planting/scheduling: 4-inch pots, one liner, six to eight weeks; 6-inch pots, two to three liners, 10 to 12 weeks. Allow 40-45 days for rooting.
Learn more about Soiree Kawaii catharanthus at SuntoryFlowers.com.
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