Hiemalis begonias have been a popular semi-shade basket plant for many years. Now, breeding break-throughs, such as the Solenia series, have given growers hiemalis-type begonias that finish faster, are mildew resistant and take full sun.
Other advantages of Solenia begonias are their ability to perform in bedding situations, as well as mixed containers. Consumers will be rewarded with a blanket of blooms in all but the most extremely hot regions (plants performed very well in our Atlanta trials.) Additionally, Solenia begonias are more wind resistant than other begonias, and much more drought resistant than New Guinea impatiens. Their branching habit also keeps them from becoming top heavy and breaking.
Growers looking for a premium basket, bedding plant or mixed container item will find Solenia begonias to be a rewarding, easy-to-grow addition to their spring and summer programs, and two new colors were recently introduced: Salmon Coral and Dusty Rose, which makes 11 varieties in the series.
Growers are advised to begin with rooted liners, transplanting four cuttings per 10-inch basket 10-12 weeks prior to sale. Like all hiemalis types, Solenia prefers a high peat content, well-drained media with a low EC and pH in the 5.5-5.7 range. Plants should be started warm. Soil temperatures of 68¡ F are a must for proper establishment. Begin a 200-ppm constant feeding program once new roots have reached the side of the container and begun to circle.
Although Solenia is day-length-neutral (this is why they continue to develop new flowering shoots all summer), it benefits from extended day lighting during the dark winter months. Providing extra light from 5 a.m. until 8 p.m. will produce a faster-growing, fuller plant. This lighting can be achieved with HID lights 4 feet above the crop or incandescent bulbs strung on 6-foot centers and should be used from October 15 until March 15. Because of this day-neutral characteristic, Solenia can be easily flowered all summer long as a season extending crop.
Once plants have grown 11?2-2 inches, soft pinch the growing tip to encourage branching. One pinch is all that is necessary to produce a high-quality basket. Keep night temperatures in the 66-68¡ F range while the plants are developing, reducing to 65¡ F for the last 3-4 weeks. Day temperatures of 72-76¡ F are optimal. Plants should be grown under high winter light and will happily withstand up to 5,000 foot-candles during this period. Once outdoor temperatures rise above 72¡ F, provide a light shade during the heat of the day to keep leaf temperatures cooler. During this mid-spring period, it is best to maintain light levels between 4,000 and 4,500 foot-candles. This environment makes Solenia a great companion crop with New Guinea impatiens.
Because of its floriferous nature, Solenia may be finished for 41?2- and 6-inch production. Given its added vigor over a standard hiemalis begonia, cultural practices with respect to height control should be implemented. Long day treatments are not recommended for 41?2-inch production, as this will promote excessive vegetative growth. Use of negative DIF has great effects on finish plant height. Whenever possible, two hours before sun-up, temperatures should be dropped 5-10¼ F. We recommend that growers trial Solenia for 41?2- and 6-inch production the first year.
Although not always necessary, a preventative spray for powdery mildew may be advised. Bayleton (Strike) at label rates could be used 4-6 weeks after planting. As mentioned earlier, this class of begonias is very mildew resistant and is only sensitive under poor growing conditions or when the plant has been stunted by over-feeding/watering early in the crop. Insects are not a significant problem with Solenia. Monitor for western flower thrips and whitefly and treat as needed with Conserve (Dow AgroSciences) and Distance (Valent).
For 41?2- and 6-inch production Cycocel (Olympic) applications at 750 ppm may be applied at bi-weekly intervals. Weekly applications may be administered; however, leaf discoloration may occur. Individual grower experience will play an integral role in the use of Cycocel. Bonzi (Syngenta) at 3-5 ppm may also be applied near finish.