Richard Bogren | 4/13/2017 6:47:01 PM
By Dan Gill
LSU AgCenter Horticulturist
(04/21/17) When Louisiana gardeners think about sunny summer flower beds, we know exactly what we want. We are looking for a bedding plant that thrives in the stifling heat and intense sunlight of a Southern summer. We want something with real color impact – a plant that produces large, dazzling flowers with a variety of colors to choose from. And stamina is critical. The plant must be able to last our entire exceptionally long summer growing season from April to November.
That’s quite a tall order, but a few excellent warm season bedding plants do a good job fitting that description. What you would likely not expect is impatiens, but that’s exactly what I’m about recommend.
SunPatiens (Impatiens hybrid) revolutionize how we use impatiens in the landscape. I must admit I did not believe impatiens would thrive in the sun when I first encountered SunPatiens in trials at the LSU AgCenter Hammond Research Station. I scoffed at the idea that impatiens could be grown right out in full sun, but I soon came to accept that very thing.
Over 10 years of trials at the Hammond Research Station and observation of plantings in landscapes have so impressed AgCenter horticulturist that they named Compact SunPatiens a Louisiana Super Plants selection for spring 2017. (Compact SunPatiens are the shortest category of SunPatiens.)
Coleus went through a similar transformation back in the 1990s. The shade-loving coleuses were bred and selected to grow well in full sun. Today, most coleuses you find at your local nursery will thrive in sun or part shade.
Sakata Seed did the same thing with SunPatiens, taking a plant adapted to the shade and breeding and selecting a sun-loving version of it. SunPatiens are hybrid impatiens that more closely resemble the New Guinea impatiens rather than traditional garden impatiens (Impatiens walleriana). The flowers are much larger, and the foliage and growth habit are more robust than garden impatiens. Some of the SunPatiens even have colorful variegated foliage like some of the New Guinea impatiens. (New Guinea impatiens have never done particularly well this far south, so SunPatiens are also remarkable in this regard.)
SunPatiens come in in three distinct series based on growth habit – spreading cultivars, compact cultivars and vigorous cultivars. Several new colors are typically added each year. The 15 cultivars in the compact series are designated as Louisiana Super Plants.
Cultivars in the compact series reach about 18-24 inches tall with an equal spread. The compact growers have a bushy growth habit that holds its shape well through summer and fall. The other cultivars – spreading and vigorous – tend to become too large during our long growing season and do not reliably maintain an attractive shape.
Flowers of all the Compact SunPatiens are large and showy and stand out from the dark green, glossy foliage. There are lots of colors to choose from, including blush pink, coral, deep rose, electric orange, fire red, hot coral, lilac, neon pink, red, pink, orange, orchid, white, royal magenta and tropical rose. You can find colors to fit virtually any color scheme. The flowers almost cover the foliage, and plants stay in constant bloom from spring to fall
A relatively new fungal disease in our area, impatiens downy mildew, has caused problems with traditional garden impatiens, which are very susceptible to this disease. With no practical controls, impatiens downy mildew can wipe out a large planting of impatiens in a short time. SunPatiens, however, are resistant to impatiens downy mildew, and you do not have to be concerned about this disease when planting them.
Now is a great time to plant SunPatiens. Experience shows that SunPatiens are best planted in the mid- to late spring (late March, April and early May) when the weather is warm but before the torrid heat of summer. Transplants planted then get established and are better prepared for the intense heat and humidity of summer arrives.
The mounding, shrub-like growth habit of this plant is striking in summer flower beds when they are covered with large colorful flowers. Plants hold their shape best when they receive full sun. If they’re planted in part shade, they will become lanky over the summer and produce fewer flowers.
SunPatiens will do best in well-prepared beds amended with generous amount of compost or other organic matter. Raised beds are recommended to provide good drainage during periods of heavy or extended summer rainfall. Plant so that the top of the root ball is even with the soil in the bed.
Do not irrigate too frequently, or you may encourage root rot. Allow SunPatiens to wilt slightly between watering, and mulch them to conserve soil moisture and prevent weeds.
The Louisiana Super Plant program is an LSU AgCenter educational and marketing campaign that highlights tough and beautiful plants that perform well throughout the state of Louisiana. Louisiana Super Plants have a proven track record with many years of reliable performance in Louisiana landscapes or have gone through several years of university evaluations and observations. Look for these plants at participating local nurseries. Louisiana Super Plants are “university tested and industry approved.”
Compact SunPatiens have flower power and are low maintenance and reliable. They work well in window boxes, patio containers, baskets and landscape beds, and last from spring until first killing frost. They are everything we want in a flowering bedding plant for summer color.
Compact SunPatiens come in a variety of colors. Photo by Dan Gill/LSU AgCenter
SunPatiens thrive in full sun. Photo by Dan Gill/LSU AgCenter
SunPatiens can be planted to grow together to produce a mass of color. Photo by Dan Gill/LSU AgCenter