With the arrival of the new growing season quickly approaching, plant enthusiasts may choose from several new butterfly bush (Buddleia) varieties for their gardening pleasure, thanks to the College’s plant breeding work headed by Mark Brand, professor of horticulture in the Department of Plant Science and Landscape Architecture.
During the summer of 2006, doctoral graduate student Bill Smith exposed Buddleia davidii seeds to ethylmethane sulfonate (EMS) in the hope of generating some novel traits in butterfly bush. EMS is a chemical that can be used to induce a higher rate of mutations in plants. When the treated seeds were grown out in 2007, two unique individuals were identified that Brand believed were important new plants.
The first plant was a variegated individual whose leaves had a yellow edge around a dark green center. Variegated plants are always popular because the foliage adds interest even when the plant is not in bloom. The foliage variegation pattern was very stable, which is not always the case with variegated plants, and light blue flowers were also produced during the summer. After trialing this plant, Spring Meadow Nursery decided to license the new butterfly bush and include it in their Proven Winners® product line as ‘Summer Skies.’ ‘Summer Skies’ was patented (USPP 22465) and also holds Canadian Plant Breeder Rights.
The second unique seedling was picked from the hundreds initially grown out from the EMS treatment was one with a unique growth form, low growing and compact, bearing thick stems, large leaves and a frosted appearance to the foliage. But the color of the flowers was lackluster. Brand wanted to retain the compact habit of the mutant seedling, but breed it to produce flowers that had stronger, more vivid colors. To do this, the mutant compact butterfly bush was crossed with four standard-sized Buddleia cultivars that have vibrant flower colors.
“Fortunately, 50 percent of the seedlings from the compact mutant plant retained the dwarf characteristic,” Brand notes. “We then selected out the plants with the best flower colors in each color group from hundreds of seedlings.” By 2010, Brand knew he had something special. He continued reproduction of the new Buddleia plants using softwood stem cuttings, and since that time each plant has retained its unique features in successive generations. He filed for four patents in June of 2015.
Brand sent the plants to Spring Meadow Nursery in Michigan, a commercial grower. The new Buddleia cultivars were first offered in 2016 exclusively at Walmart, as the Soda Pop series of butterfly bushes within the Better Homes and Garden line. The four cultivars are Buddleia davidii ‘UCONNBD599’ Soda Pop Lavender, ‘UCONNBD603’ Soda Pop White, ‘UCONNBD604’ Soda Pop Blue, and ‘UCONNBD610’ Soda Pop Purple.
“These new Buddleia are dramatically different in their appearance than anything else on the market,” Brand says. “There are other dwarf plants, but these have big leaves, big chunky stems and full-sized flowers on a plant that stays between three and four feet tall, even when left unpruned. That’s what makes them unique. They also exhibit good cold hardiness, which is needed when growing butterfly bushes in hardiness zone 5.”
The response to the new line was so positive that Spring Meadow bred the new cultivars with some deeper color plants to expand the line. These plants are part of their Proven Winners® line, under the Buddleia Pugster™ Series. “Our material was so impressive it led to an additional line of Buddleia touted as a major breakthrough in butterfly bushes,” Brand points out. “I expect there will be more future butterfly bush introductions that will trace their genetic roots back to the compact mutant that was produced in our breeding program.”
Royalty monies from plant cultivars help to fund continued research by students. So far, the royalty income has gone toward lab supplies and other necessities such as plant media, containers and fertilizer.
“I think the bulk of our royalty funding is yet to come,” Brand says. “We have quite a few cultivars out there including an ornamental switchgrass (Panicum), several varieties of butterfly bush and some chokeberry (Aronia). We also have a number of plants in trials with commercial growers and some, such as a compact form of purple-leaf sand cherry (Prunus), and sterile barberries (Berberis), are licensed and in the production pipeline.”