The North Dakota Agricultural Experiment Station and NDSU Research Foundation have introduced two new woody plant selections this year. They include Cinnamon Curls Dwarf Korean Birch and Northern Empress Japanese Elm. The selections were developed by the NDSU Woody Plant Improvement program, under the direction of Todd West, associate professor of plant sciences.
Cinnamon Curls Dwarf Korean Birch is a distinctive dwarf selection of Korean birch that is slow growing and has a rounded, compact growth habit. A notable characteristic is its attractive creamy white exfoliating bark with cinnamon colored undersides curling in strips. This feature is noticeable in all seasons but especially during the winter months when the trunk and branches are fully exposed.
At maturity, Cinnamon Curls stands nine feet tall with a spread of nine feet. Its foliage is bright green in summer months, changing to bright golden-yellow fall coloration. It prefers full sun to very light shade, performs best in well-drained soil and is tolerant of higher pH soils. It is hardy to USDA climatic zone 4a.
This tree has very good insect and disease resistance. Recommended use for this tree selection is in limited space landscapes such as business and home entryways, patios and small outdoor living space areas where an attractive focal point plant is desired.
Northern Empress Japanese Elm is a hardy small to medium sized elm with a rounded crown, open branching, and attractive summer and fall foliage. A unique, small statured elm selection with excellent dependable burgundy-red fall coloration, it adds a useful elm cultivar to diversify the availability of elm selections returning to the landscape. There is only one other elm cultivar that has burgundy fall color, which is only hardy to USDA climatic zone 5.
At maturity, Northern Empress stands 28 feet tall and has a spread of 24 feet. It is much smaller than the species, which can reach up to 100 feet tall at maturity. Its foliage is medium green during the summer months. Fall foliage changes from green to apricot-orange to burgundy-red before leaf drop. This tree selection prefers full sun and well-drained soils. It is pH adaptable and tolerant of higher pH soils. It has shown moderate to good drought tolerance and is hardy into USDA climatic zone 3.
This tree has good insect and disease resistance. It is minimally affected by black leaf spot of elm and possesses inherent resistance to elm leaf beetles and Dutch Elm Disease.
Recommended use for this tree is as a small to medium sized ornamental tree in urban landscape planting areas. Size and form permit use in smaller homeowner and business landscapes, parks, and boulevard plantings. This is especially relevant where available space or overhead power lines are a concern and where hardiness of other elm cultivars may be an issue.
The NDSU Woody Plant Improvement program has been serving the Northern Great Plains for 60 years, beginning germplasm trial evaluations in 1954. In 1974, NDSU purchased an 80-acre farm near Absaraka, North Dakota, to be established as the NDSU Horticulture Research Farm and began trial plantings that fall. Approximately 45 acres of the research farm is used for evaluation, selection and breeding of woody ornamental plants.
The main portion of the research farm is the center 35-acre plot dedicated as the NDSU Dale E. Herman Research Arboretum. Named after Dale E. Herman, NDSU professor emeritus who developed the program for nearly 40 years, the research arboretum is the most extensive collection of woody ornamental plants in North Dakota and the Northern Great Plains.
NDSU woody plant introductions are being propagated for sale by commercial wholesale firms in four countries: Australia, Canada, England and the United States, including 14 states and 35 nurseries. This project has introduced 53 superior woody plants for production and sale with increased disease tolerance and winter hardiness for landscapes. For more information about the program, visit www.ag.ndsu.edu/plantsciences/research/woody-plants/.
NDSU is recognized as one of the nation's top 108 public and private universities by the Carnegie Commission on Higher Education.