Dr. Rick Schoellhorn, director of new products for Proven Winners provided a window to the world of how plants come to us, the buying public. Schoellhorn was one of the four speakers at the Proven Winners Indoor Garden Extravaganza in Atlanta last week.
Proven Winners, he said, screens and grows 15,000 plants each year in order to find three that they can introduce to the country’s garden centers. Four hundred plant breeding companies and individuals submit plant possibilities for them to consider.
“One of the reasons plants discovered or bred in Japan do so well in the American Southeast is that Japan is even hotter and more humid,” said Schoellhorn.
For example, Raspberry Blast Supertunia was bred in Japan for its heat and humidity tolerance.
“Growers and home gardeners want two different things,” Schoellhorn said. “Growers want compact balls of generic items and gardeners want plants that perform so well that they are surprised.”
He said the only way gardeners can get the things they want in their local garden center is to go to the garden center in the fall and tell them what they want to grow the next spring.
“Vista Bubblegum petunia is the best petunia choice for the southeast,” Schoellhorn said. “That plant went through two years of testing before it was introduced. It had to succeed in MI, NH, FL, CA and Germany.”
After a plant is selected, the tissue culture is grown into liners. Three growers provide rooted liners full of plant plugs to 8,000 growers.
Schoellhorn came to Proven Winners from previous career as an agricultural sciences professor and garden center owner. He lives in Gainesville, FL but his work keeps him on the move, travelling the world.
“The plants I’m working on now are for your 2012-13 gardens,” Schoellhorn said. “At the trial gardens in Gainesville, we grow everything on silver, plastic mulch over the winter so we can observe the plants’ tolerance to heat and cold.”
Schoellhorn said he is particularly interested in plants that can survive the hot nights and high heat of southern gardens. Most plants selected for and grown in the rest of the U.S. are dead by mid-summer.
“Annuals will look their best longer and keep blooming if they are fertilized regularly,” Schoelhorn said. “Liquid fertilizer is good for patio pots and greenhouse use. Slow release granules are good to apply to the soil”
Spray- on fertilizer needs to sit on the plants’ leaves 6-hours in order to be absorbed. If it rains or overhead watering is used, the fertilizer is washed into a nearby creek.
Slow release fertilizer works when moisture and soil microbes break it down and make the nutrients available to the plants. During periods of high heat, plants need more fertilizer, so use slow release twice each summer.
Good plants for the southeast include Goldilocks Rocks Bidens, Aubrieta, Alligator Tears Color Blaze Coleus, Blue Mohawk juncus or rush for aquatic gardens, Vertigo Pennisetum purpureum, Heliotrope Simply Sensational, Leucanthemum Daisy May, Gold Dust Mecardonia and Superbells Blackberry Punch .
“Try to get Superbells/Supertunias in the fall,” Schoellhorn said. “Plant them in pots and overwinter them inside. (They can tolerate 20 degrees.) Put them out in the spring and they’ll pop out.”
For our area he recommended a graceful, Mahogany-red fountain grass, Vertigo Pennisetum purpureum or Pearl Millet, that grows to 5-feet tall in one season.