Wanted: Plucky roses with impressive landscape performance coupled with serious pest and disease resistance.
It’s not fiction. Texas A&M University has found 17 cultivars that deliver all of those desirable traits. Deemed EarthKind roses, the plants have been through years of rigorous testing including very little irrigation and absolutely no pesticide or fertilizer applications. The plants are mulched, but the soil is not amended with compost.
EarthKind Roses can be any type from floribunda to hybrid tea. EarthKind roses range from wildly popular cultivars such as Knock Out to one that’s been around more than a century such as Duchesse De Brabant.
But if a test subject is devoured by aphids, smothered with blackspot, succumbs to heat or shrivels from the cold, it won’t join the ranks of the coveted EarthKind group.
“Once they’re established in the landscape, EarthKind roses will be very drought and heat tolerant,” said Steve George, horticulturist at Texas AgriLife Extension and father of the EarthKind rose program. “EarthKind roses have such good disease and pest resistance, they’ll almost never have to be sprayed.”
Northern exposure
The Texas-born EarthKind program has caught the attention of universities in other states. The University of Minnesota, Kansas State, Iowa State, University of Nebraska-Lincoln and Colorado State are testing EarthKind roses.
David Zlesak, assistant extension professor at the University of Minnesota, traveled south in January 2007 to meet with George and learn more about the program.
“One of the major needs we have in the North is not only disease resistance but winter hardiness,” Zlesak said.
Zlesak returned to Minnesota and planted a 20-cultivar EarthKind rose trial garden in Rosemont, Minn. The first year is strictly for establishment, and performance data will be recorded during years two through four. Zlesak will announce some of the “winners” by the end of year four. Like the Texas EarthKind trial gardens, the Minnesota test subjects will not be sprayed. The only difference is deadwood will be pruned in spring, Zlesak said.
National collection
George partnered with Pam Smith, horticulturist for the city of Farmers Branch, a Dallas suburb, to plant a 100-cultivar test garden. Results from this garden, along with the other university tests sites, will produce a national EarthKind collection.
About 80 percent of the roses in the Farmers Branch study are winter hardy to Ames, Iowa, George said.
“And so we want to see how far south they will come, because from that group we hope that we will find a number, or at least a handful that will make it from Houston to Minneapolis, L.A. to New York City, with no sprays and no fertilizer,” George said.
The roses will eventually be tested using treated wastewater from sewage plants.
The city of Farmers Branch, which contributed $25,000 to the project, will maintain the garden, Smith said. The Houston Rose Society donated an additional $25,000, said Gaye Hammond, the society’s past president and serious EarthKind supporter.
When Texas A&M identified the first 11 EarthKind roses in 2003, Hammond “was blown away,” she said.
“I asked, ‘What’s next?’ And when A&M said they were done, I said, ‘Oh no you’re not. This isn’t enough. We need more roses in the EarthKind program,’” Hammond said.
Texas A&M Commerce is testing 20 varieties, including some that are hardy to Canada, said Derald Harp, assistant professor of agricultural sciences at Texas A&M Commerce. The Commerce test garden has phosphorous-deficient soil, Harp said.
Harp expects some “solid results” from his test by next fall.
Wholesale production
Mark Chamblee, owner of Chamblee’s Rose Nursery in Tyler, Texas, has been growing EarthKind roses since the program’s inception. He grows all 17 EarthKind varieties and grew the roses planted in the Farmers Branch test garden.
“I’m amazed by the excitement from consumers and master gardeners, and I’m excited about the program’s success. Success sells,” Chamblee said.
Chamblee sells EarthKind varieties wholesale, retail and mail-order. EarthKind roses for wholesale are available in 4-inch liners, 1-gallon, 2-gallon and 3-gallon containers. The 1-gallon roses are good for shifting up, he said.
EarthKind roses are easy to propagate and grow, Chamblee said.
“They have a better vascular system and a better root system,” he said. “And they’re not chemically dependent when they go into the landscape.”
In production, the EarthKind roses are grown in media similar to what is recommended in the landscape -- shredded hardwood mulch, compost and horticulture sand.
Growers will cut down on the use of pesticides with EarthKind roses in production.
“Selecting more disease-resistant varieties allows us to have a biorational method of pesticide application,” Chamblee said. “We’re focused more on plant health than disease control.”
Last summer Chamblee experimented with Ellepots in propagation. The pots shortened production time, but Chamblee had to restructure the amount of irrigation and plant nutrients. This year all of Chamblee’s propagation will be in Ellepots.
Gardeners want care-free roses
In the landscape, EarthKind roses need eight hours or more of full, direct sun and good air movement over the leaves.
Before planting, till in 3 inches of compost.
Keep a 3-inch layer of mulch around the roses year-round.
Fertilize in March, June and lightly in late August.
EarthKind roses are highly tolerant to pests, but not immune. Pesticides are not necessary as long as the gardener doesn’t mind occasional, minimum leaf drop.
For more: Steve George, Texas AgriLife Extension, (972) 952-9217; s-george3@tamu.edu; http://earthkindroses.tamu.edu.
Photo courtesy of Chamblee's Rose Nursery
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- Kelli Rodda
May 2008