Betula occidentalis Hook. Water birch. This large shrub or small, clump-forming tree is related to paper birch, but it has smaller leaves and orange to brown colored bark similar to Prunus maackii. In its native habitat in the western US, it is often found growing along streams and it may be more tolerant to flooding than paper birch. This particular population, while keying out as B. occidentalis , does have leaf characteristics similar to paper birch and may represent an intermediate form.
PI 495882 was collected along Clear Creek between Georgetown and Idaho Springs, Clear Creek County, Colorado, elev. 2438 meters by J. Klett and J. Feucht in 1984. (Soil pH at this site was 6.5) Probable hardiness USDA Zone 3b.
Betula pendula Roth European white birch. This white-barked birch was performing well in Stavropol, USSR where it was growing in an urban setting. The climate of this site is similar to the warmer and drier parts of our region. However, the collector was told that these trees came from seed that was collected in the Caucasus Mountains, suggesting that they may also have superior cold hardiness. Since the severity of attack of bronze birch borer is inversely related to the degree of climatic adaptation of the tree, this accession may be worthwhile to test for birch borer resistance in those areas where borers limit the use of white-barked birches.
PI 502295 was collected in a city park in Stavropol, USSR (about 45 degrees N, 42 degrees E) in 1982 by M. Rumbaugh. Probable hardiness USDA Zone 4a.
Cornus macrophylla Wallich Bigleaf dogwood. This small tree is rarely seen in the United States. It has a prominent show of flowers late in the summer and has very attractive, large bright green leaves. Michael Dirr describes this species in his Manual of Woody Landscape Plants, based on observations of it at the Arnold Arboretum. It looks promising for urban sites with sufficiently mild winters.
Ames 10178 was collected at Murree, Punjab Province, Pakistan, 33 degrees 54 minutes N, 73 degrees 24 minutes E, elev. 2100 meters by M. Thompson and D. Brenner in 1988. Probable hardiness USDA Zone 5b.
Ligustrum obtusifolium Sieb. & Zucc. Border privet. This dense, wide-spreading shrub is suitable for hedges and windbreaks. It does not have an impressive show of flowers or fruits, but its form is less coarse than many other privets. The winter hardiness of this accession should be near the limits of the genus, considering the experiences that the NRCS has had with this accession in Michigan.
PI 477010 was selected by the NRCS Plant Materials Center in East Lansing , Michigan and originated from a collection made in Lapeer County, Michigan in 1973. Probable hardiness USDA Zone 4b.
Lonicera maackii (Rupr.) Maxim. Amur honeysuckle. This large, open shrub has clean green foliage and showy red fruits in the autumn. It does not give the floral display of L. tatarica cultivars, but is not particularly susceptible to the Honeysuckle Leafroller Aphid, which has caused unsightly damage to L. tatarica and related species. In Iowa, this species is not as invasive as L. tatarica, but farther south and east its invasiveness must be considered a problem in many settings.
PI 477998 was selected from seed of L. maackii received from Canada in 1954 by the NRCS Plant Materials Center in Bismarck , North Dakota. Probable hardiness USDA Zone 2.
Pterostyrax hispidus Sieb. & Zucc. Fragrant epaulettetree. This small tree is fast growing with large thin leaves that look tropical in the greenhouse, but that may fall apart in a midwestern storm. Large panicles of fragrant white flowers borne in June are this species' strongest attribute. Ideally it should be planted in a sunny site protected from strong winds. This collection should be more cold hardy than typical, considering its good performance at the Montreal Botanical Garden .
Ames 8079 was grown from seeds obtained from the 1988 seed exchange of the Montreal Botanical Garden. These seeds were collected from an accession that originally was obtained from the Hesse Nursery in Germany. Probable hardiness USDA Zone 5a.
Quercus phellos L. Willow oak . This large oak is widely used as a street tree in acid soil regions of the southeastern US. It has a much finer branching texture than most other oaks. It has dark green, entire leaves that resemble small Q. imbricaria leaves, that can turn rich wine or gold colors in the fall. This species is successfully grown as far north as Columbia, Missouri, but populations have not been adequately tested farther north.
Ames 4723 is from a southeast Missouri source with seeds donated by the Missouri State Forestry Nursery, Licking, MO in 1985.
Ames 4724 is from a central Tennessee source with seeds donated by the Missouri State Forestry Nursery, Licking, MO in 1985. Probable hardiness USDA Zone 5a on acid soils.
Rhus copallina L. Shining sumac. This pinnately compound leaved sumac has glossy foliage with brilliant bright to dark red fall color. Unfortunately, many populations of this species do not flower in Ames until September and are still growing at the fall freeze, leading to poor coloration and dieback. This accession comes from the western part of this species' range and may be well adapted to heat and drought stress and more alkaline soils than typical. Superior selections may be propagated easily from suckers and root cuttings. I hope to be able to distribute more northern sources of this species in future years.
PI 607437 (Ames 7764) was collected in Montgomery County, Kansas by the Morton Arboretum and was obtained from their seed exchange in 1987. Probable hardiness USDA Zone 5a.
Rosa setigera Michx. Prairie rose. This rose is native to the southern midwest and the southeastern states. It is the parent to some of our hardy climbing cultivars. Its mature form is a wide-spreading mass of long arching canes. The floral display is quite showy, with true pink flowers arranged in corymbs prominent in late June. The fruits are similar to R. multiflora, but larger. This could make an excellent barrier plant, in the style of Berberis koreana or Robinia hispida, or could be trained as a climbing rose. This collection was made at the northwestern edge of its native range.
PI 495616 was collected in Indian Cave State Park, Nemaha Co., Nebraska, elev. 344 meters by M. Widrlechner and E. Paparozzi in 1984. Probable hardiness USDA Zone 4.
Sorbaria sorbifolia (L.) A.Braun Ural false-spiraea. This suckering shrub is extremely tough and disease free. It is easy to propagate from seeds, divisions or cuttings. With its range of adaptability and striking midsummer floral display, I've always wondered why it is not grown more widely. It develops into a saleable container plant quickly and often flowers after only a single year. I can think of only two reasons: the lack of a good trade name and its strong suckering capability on good sites. On a fairly sunny hillside or in a naturalized setting, or even for urban container plantings, this plant could work very well. Ames 7778 was obtained in 1987 from the Index Seminum of the Arboretum Kostelec, Kostelec nad Cernymi lesy, Czechoslovakia. Probable hardiness USDA Zone 2.
Sorbus reducta Diels Chinese dwarf mountain ash. This shrubby mountain ash may be very useful in the residential and urban landscape. It has not been widely grown in the US, but was recently released by the University of British Columbia Botanical Garden as part of its Plant Introduction Scheme. This plant is released only for testing.
Ames 8371 was grown from seeds donated by A. Bruce MacDonald, University of British Columbia Botanical Garden. Probable hardiness unknown.
Syringa reticulata subsp. pekinensis (Rupr.) P.S. Green & M.C. Chang Peking tree lilac. This lilac is one of the most graceful and attractive small-tree taxa on the Iowa State University campus. It has a wide range of adaptation to environmental conditions throughout our region. There have been at least two superior cultivars selected from this species, although both belong the the subspecies reticulata, 'Ivory Silk', which originated in Ontario at Sheridan Nurseries, and 'PNI 7523', which has been trademarked as Regent™. The trademark is the property of Princeton Nurseries, which selected the cultivar.
PI 478008 was selected by the NRCS Plant Materials Center in Bismarck , ND from a collection originally made in Morden, Manitoba by J. McDermand in 1954. Probable hardiness USDA Zone 3a. This particular population was tested at Bismarck, ND and may prove better adapted to extremes of drought and cold than many other cultivars.
Viburnum lentago L. Nannyberry. This large shrub is fairly common in the trade. It grows quickly, has bright green foliage that often turns a strong red color in autumn, and attractive edible fruits. This plant is dependable throughout our region and only mildew late in summer sometimes mars its appearance. I would not normally distribute this plant for trial, but I received it from the Agriculture Canada Research Station in Morden, Manitoba as V. prunifolia, and had expected to be giving you a blackhaw more hardy than typical. With this collection's northern source, it may have a somewhat shorter period of annual growth than typical and may also color up earlier in autumn.
Ames 2813 was grown from seed donated by
the Agriculture Canada Research Station at Morden, Manitoba in 1986. Probable
hardiness USDA Zone 2.