Researchers at the Landscape Plant Development Center are in the business of stressing out. It’s not the hours or the workload. They’re putting plants through the rigors of environmental and biological stresses and looking for the most tolerant selections.
“Customers of nursery crops want plants that require little or no maintenance,” says Harold Pellett, executive director of the center.
Besides stress tolerance, the center also emphasizes the development of smaller-stature plants to better fit small properties; plants with season-long interest and color; improved varieties of native species and sterile cultivars of invasive species.
“The use of native plants is gaining popularity because of their adaptation to regional climatic conditions,” Pellett says. “However, even though they are very tolerant of the normal climatic conditions of a region, they are not always well-adapted to the soil conditions found in the man-modified environments in which we wish to use them.”
Developing sterile cultivars will eliminate fruit litter and invasiveness, and improve flowering. The center has verified tetraploids of crabapple, Acer platanoides and A. ginnala. Researchers also have noted several pear selections that appear to be sterile. The center has found some Buddleia seedlings that appear sterile or of low fertility.
Cooperative effort. The Landscape Plant Development Center, headquartered in Mound, Minn., is a nonprofit organization with research stations in Donald, Ore. and Lake Elmo, Minn. Sarah Doane is the station manager in Donald, Ore.
The center also partners with several universities, including Washington State University – Puyallup, where Rita Hummel performs intensive Pyrus studies. The center develops and evaluates plants that are adapted in different geographic regions.
Breeding projects include Pyrus, Carpinus, maple, mountain ash, clematis, Weigela, Diervilla, Buddleia and oak. The center has introduced ‘Center Glow’ ninebark, ‘Silver Ball’ pear, ‘Center Star’ clematis and ‘Cool Splash’ diervilla.
And the center is continually working on future introductions. “We have promising selections in many genera including Pyrus, Acer, Carpinus, Physocarpus, Buddleia, Weigela, Cornus, Forsythia, Viburnum, Cephalanthus, Ceanothus and Diervilla,” Hummel says. Hummel is excited about one hybrid pear in particular that combines four species, including Pyrus ussuriensis, the most cold-hardy of the genus. It also has a pyramidal branching habit that resembles a conifer, she says. In 2008, Doane made crosses between Acer pseudosieboldianum and cultivars of A. palmatum with red foliage.
The author is editor of Nursery Management magazine. Send her an e-mail at email@example.com.