Growing Together: Hot new trees and shrubs, courtesy of NDSU's breeding program
FARGO -- No one could possibly look forward to a frigid winter, right? Wrong.
Dr. Todd West, North Dakota State University professor and Woody Plants Improvement Project director, relishes winter temperatures that plunge to the depths of our region’s climate. West is optimistic about cold with good reason: His research involves developing new tree and shrub varieties well-adapted to the Upper Midwest, and a necessary characteristic is their ability to survive our winters, including winters that dive to record low temperatures.
During pleasant winters, potential new woody plants aren’t subjected to properly frigid conditions. It’s during a really cold winter, called a “test winter,” that new varieties being developed can be properly assessed to see if they’re truly winter-hardy in our region.
Developing a new tree or shrub cultivar is a long process — up to 30 or 40 years — including decades of testing, plus time for wholesale nurseries to propagate and distribute the new product to retail garden centers. The sooner a tree or shrub is subjected to a few test winters to separate the wheat from the chaff, the faster the process moves forward.
NDSU’s woody plant breeding and selection program is invaluable to the Upper Midwest and has been prolific, introducing 58 new cultivars. Without this program, we’d be dependent on trees and shrubs developed elsewhere, usually in milder climates, many of which aren’t suited for our zone 3 and 4 climates, alkaline soil and lower annual moisture.
The NDSU program adds diversity of plant types, which is badly needed as new diseases and insects cause loss of previously adapted types, like ash.
NDSU cultivars available to nurseries
- Spring Welcome Magnolia: Outstanding winter-hardy selection that blooms reliably even after early spring frosts. Its dense, rounded oval form is well-branched with flowers light pink in bud, gradually opening to pristine white. Can be grown single or multi-trunked as a large landscape shrub or small specimen tree, growing to 20 feet in height.
- Northern Herald Eastern Redbud: A rare, winter-hardy redbud covered in pink flowers, forming a small, rounded ornamental tree to 20 feet in height.
- Northern Flare Sugar Maple: A dependably winter-hardy northern sugar maple selection with beautiful orange-red fall color. Tolerates soils higher in alkalinity than other sugar maples, making it a good choice for the Red River Valley and westward.
- Royal Splendor Norway Spruce: Striking evergreen tree with a narrowly pyramidal form to 40 feet in height. Rich, emerald-green needles are highly resistant to needle cast diseases affecting other spruce types.
- Prairie Statesman Swiss Stone Pine: Rich emerald-green needles on an elegant, stately tree with a narrowly erect, strikingly dense habit, growing to 30 feet. Extremely cold-hardy and drought-tolerant, it's an outstanding evergreen landscape specimen tree.
- Prairie Dream Paper Birch: Exceptional snow-white exfoliating bark and brilliant golden-yellow autumn foliage color. Superior adaptation and stress tolerance, and it's resistant to bronze birch borer.
- Blueberry Delight Juniper: Selected from North Dakota’s Badlands, this low-growing, 20-inch, drought-tolerant evergreen spreads outward with rich green growth with silver-blue hues. Covered in attractive blueberry-like cones.
- Northern Tribute River Birch: Striking ivory-colored bark exfoliates to copper-bronze. It's winter-hardy, growing well even in compacted, dry soils. A beautiful specimen tree to 35 feet.
- Prairie Stature Oak: Outstanding red autumn color and dense pyramidal form make this a good choice as a shade, boulevard or specimen yard tree.
- Northern Empress Japanese Elm: A very hardy small- to medium-sized tree to 28 feet, with a rounded crown and striking autumn foliage colored apricot-orange to burgundy-red.
NDSU cultivars now in the works
- Summer Aspire Japanese Tree Lilac: A tall, upright tree lilac with a narrower form and greater height (35 feet) than other cultivars. Large, showy, creamy white flower panicles in late June.
- LavaBurst Ohio Buckeye: A narrow upright northern-hardy selection with bright green leaves changing to brilliant orange-red in autumn. Compact growth habit is ideal for limited space sites where a full-sized buckeye isn’t suitable. Grows to 28 feet.
- Cinnamon Curls Korean Birch: A distinctive dwarf birch with attractive creamy white exfoliating bark with cinnamon-colored curls especially visible during winter. Small focal point tree growing to only 9 feet high.
- Katsura Tree: Rare, winter-hardy selection with leaves opening red, changing to blue-green. Autumn color is a brilliant mix of yellow, apricot and pink, all on the same tree. Medium-sized to 25 feet.
Don Kinzler, a lifelong gardener, worked as an NDSU Extension horticulturist and owned Kinzler’s Greenhouse in Fargo. Readers can reach him at email@example.com.