Plant Descriptions of
Accessions Offered in 2003
Betula
papyrifera Marshall BETULACEAE. Paper
birch. Across the North Central region, the lives of
white-barked birches are often cut short through damage caused by the feeding
of the bronze birch borer (Agrilis anxius). When our native paper birch is cultivated
in urban settings away from its natural habitat, it is generally so short lived
that its cultivation cannot be recommended.
The search for paper birch selections from native populations with
better tolerance to urban stresses, such as heat, drought, and flooding, has
not yet resulted in superior cultivars in the nursery trade. But that may soon
change. Betula papyrifera ‘Varen’ is a clonal selection,
propagated by tissue culture, that is being released by Dr. Dale Herman, Larry
Chaput, Dr. ZongMing Cheng, and Dr. David Dai of
Ames 26922
‘Varen’ PPAF, Prairie Dream TM was supplied by Dr. Dale
Herman, North Dakota State University, Fargo, ND in May 2002. Plants were micropropagated from shoot
meristems. To meet the requirements of
Probable hardiness to USDA Zone 3a. Plants offered are approximately 1.2 meters tall.
Betula pendula Roth BETULACEAE.
European white birch. This birch is more commonly and successfully
cultivated throughout the North Central region than is our native paper
birch. Yet, it too generally succumbs to
damage from bronze birch borers. Our
1990 introduction of this species, PI 502295 from southern
Ames 25492 was collected in Molodetskiy, Sumy Oblast,
Ukraine, 50 deg. 19 min. 33 sec. North Lat., 34 deg. 40 min. 28 sec. East
Long., at an elevation of 190 meters, where it was growing in full sun on a 5%
slope with a western exposure. The soil
was a clay loam with good drainage. Associated vegetation included
Ames 25493 was collected halfway between Kaplunovka and Koziyevka, Kharkiv Oblast, Ukraine, 50 deg. 09 min. 00 sec. North Lat., 35 deg. 09 min. 15 sec. East Long., at an elevation of 200 meters, where it was growing in an open site on a hilltop. The soil was a clay loam soil with good drainage. Associated vegetation included Quercus robur, Acer campestre, Sambucus, and Alnus.
Probable hardiness
to USDA Zone 3. Plants offered are
approximately 1 to 1.3 meters tall.
Carpinus betulus L. BETULACEAE.
European hornbeam. In Manual
of Woody Landscape Plants, Dr. Michael Dirr considers this species to be among
“the very finest landscape trees; excellent for screens, hedges,
groupings… withstands pruning as well as or better than European
beech” (which is also being offered this year). The comparison is fitting, as the two
species, hornbeam and beech, are worth comparing. Both have smooth, gray bark, thick,
narrowly-ovate to oblong leaves, and sharply pointed vegetative buds. Our Midwestern experience with C. betulus has usually been with the
cultivar ‘Fastigiata.’ That and most other selections likely
originated from trees cultivated in
NA 69995 (Ames 25496) and NA 69996 (Ames 25497) were collected as seed by Mark Widrlechner, Bob Schutzki, Vasiliy Yukhnovskyy, and Victor Sviatetsky in September 1999.
NA 69995 was collected 3 km southwest of Gerezhenovka, Cherkasy Oblast, Ukraine, 48 deg. 43 min. 40 sec. North Lat., 30 deg. 17 min. 25 sec. East Long., at an elevation of 225 meters, where it was growing at the edge of forest along highway on a gentle slope with a northwestern exposure. The soil was clay loam with fair drainage. Associated vegetation included Robinia, Acer campestre, Fraxinus, and Sambucus nigra.
NA 69996 was collected in Kremenets’/Feshchuki, Ternopil Oblast, Ukraine, 50 deg. 07 min. 11 sec. North Lat., 25 deg. 44 min. 31 sec. East Long, at an elevation of 355 meters, where it was growing in a forest on a large hill above a sanitarium. The soil was sandy loam with good drainage. Associated vegetation included Acer pseudoplatanus, Pinus sylvestris, Betula pendula, and Quercus petraea. This was the only site where the team found Q. petraea.
Probable hardiness to USDA Zone 4b. Plants of NA 69995 range widely in size between about 30 and 90 cm tall. Plants of NA 69996 are approximately 80 cm tall.
Cornus mas L. CORNACEAE.
Corneliancherry dogwood. This
large shrub to small tree captures attention from a distance in early spring,
when its branches are clothed in small, bright yellow inflorescences. It is also notable for its clean, dark green
foliage, which nicely contrasts with shiny red, oblong fruits. The fruits can be used to make tasty
jellies. In the late winter, the
spherical, short-stalked flower buds provide close-up interest, as can the
bark, which in the best specimens exfoliates to expose patches of various hues. In 1976, C.
mas, PI 377804, was distributed in the NC7 Trials, where we learned that
winter hardiness, especially related to floral damage, can limit the zone of
adaptation. PI 377804 was collected in
Probable hardiness to USDA Zone 4b. Plants offered are approximately 1.2 meters tall.
Fagus sylvatica L. FAGACEAE.
European beech. On suitable
sites, beech trees, with their smooth, silver-gray bark and stately, formal
branching structure make highly desirable landscape specimens. They prefer moist, well-drained sites with
somewhat acidic soil but are limited by heat, drought, and extreme low
temperatures. Fagus sylvatica reaches the eastern edge of its native range in the
Probable hardiness to USDA Zone 5. Plants offered are approximately 60 cm tall.
Lonicera alpigena L. CAPRIFOLIACEAE.
The source history indicates that this accession originated
from the Komarov Botanical Institute in
While I do not expect that this accession poses a threat to natural habitats, given its attractive fruits and the propensity of other Old World Lonicera species to naturalize in our region, it would be advisable to monitor this accession for natural reproduction, report such reproduction back to the NC7 project if observed, and then remove any reproducing plants and their progeny.
Probable hardiness to USDA Zone 4? (based on its origin in
Tilia cordata L. TILIACEAE.
Littleleaf linden. This
popular shade tree may need no introduction, but it is important to remember
that the majority of littleleaf lindens growing in our region represent an
extremely narrow genetic base of just a few clonal selections. While litteleaf linden has an extremely wide
native range across
NA 70011 (Ames 25553) was grown from seed collected by Mark
Widrlechner,
Probable hardiness at least to USDA Zone 4. Plants offered are variable in size, ranging between about 30 and 110 cm tall.
Viburnum rufidulum Raf. ADOXACEAE.
Rusty blackhaw viburnum. This
species is among the most attractive of viburnums native to our region. Among its strongest attributes are glossy, leathery leaves, which often turn an
intense, wine-red color in autumn, inflorescences and fruiting clusters that
are at least as large and showy as its more commonly cultivated relative, V. prunifolium, and, on older plants, a
distinctive, dark, blocky bark, resembling that of Cornus florida. Its
fruits are edible and attractive to birds, and its overwintering and freshly
opening vegetative buds are thickly covered with rusty hairs. Where it is native in the southern parts of
our region, it is occasionally cultivated, but low winter temperatures may
limit its utility in sites colder than Zone 5.
Some populations are not even hardy to that extent. For example, Dr. Julian Steyermark in Flora
of Missouri noted, “In northern
Ames 21668 ‘Royal Guard’ was propagated by stem cuttings from a
shrub supplied in May 1993 by the Holden Arboretum, Kirtland, OH, which in turn
had received it that same spring from Ned Rader, Ned's Nursery, 18580 Chambers
Road, Amanda, OH 43102. In an article
entitled, “Viburnum Vibrancy” (American Nurseryman 15 Mar 1999, pp.
30-36), Dr. Harrison Flint indicated that “most plants of this species (V.
rufidulum) used in the Midwest originated from seed collected in
Probable hardiness to USDA Zone 5a. Plants of
Links:
Back to list of 2003 plants
All Accessions Evaluated from 1984-Present
NC7 Woody Ornamental Trial Homepage
NC7 Plant
Introduction Station Homepage
Please send questions or comments to Mark Widrlechner at nc7mw@ars-grin.gov