NC7 Woody Ornamental Evaluations
10-year Performance Summaries for Accessions Offered in 1990
Fifteen out of eighteen sites reported maintaining this accession through
the 1-year trial period; eight sites reported maintaining it through the 5-year
trial period; and five sites located at Absaraka, ND; Carrington, ND; Bismarck, ND; Fairbanks, AK;
and Fort Collins, CO reported
maintaining it through the 10-year trial period. Plant loss was attributed to drought
(Urbana, IL) and moderate to severe injury due to leaf disease (Absaraka, ND
and Carrington, ND), borers (Ames, IA and Fort Collins, CO), moose browsing
(Fairbanks, AK), and winter injury (Grand Rapids, MN).This accession proved to
be hardy to at least USDA Plant Hardiness Zone 3b.Average plant height was
1.95m and 2.80m after the 5-year and 10-year trial periods, respectively. Average plant spread was 1.93m and 2.65m
after the 5-year and 10-year trial periods, respectively. Emerging leaves are semi-glossy turning dull
with potential for yellow fall color (Grand
Rapids and Carrington) which was dependent on disease
pressure. Foliage quality was rated as
either average or low due to a leaf spot pathogen that resulted in premature
leaf drop. Various cooperators
indicated little to no drought tolerance and susceptibility to bronze birch
borer, birch leaf miner, and an unidentified leaf spot. This accession is best suited for moist
areas located in the western Great Plains. Only the Bismarck, ND
site recommended this species on the basis of its overall performance.
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Betula pendula
PI 502295
Eighteen out of twenty sites reported maintaining this accession through the
1-year trial period; fourteen sites reported maintaining it through the 5-year
trial period; and eight sites located at East Lansing, MI; Fort Collins, CO; Chanhassen, MN; North Platte, NE; Carrington, ND; Urbana, IL; Absaraka, ND;
and Fairbanks, AK reported maintaining
it through the 10-year trial period.
Average plant height was 3.12m and 18.70m after the 5-year and 10-year
trial periods, respectively. Average
plant spread was 2.00m and 3.61m after the 5-year and 10-year trial periods,
respectively. This accession was hardy to at least USDA Plant Hardiness Zone
3b.Plant habit was variable from oval, loose and open, to slightly
drooping. Leaves were described as
glossy with excellent yellow fall color (Absaraka, Chanhassen, North
Platte, Carrington, and Fort Collins).Ratings for this accession after
the 5-year period were very high due to fall color, vigor, vibrant white bark,
and insect resistance. However, results
of the 10-year period at these same locations indicated that plants were
suddenly attacked by bronze birch borers during the eighth or ninth growing
season. However, plants that did
survive through the 10-year period continued to have excellent, white colored
bark and yellow fall color. Surviving plants should be reevaluated for
their borer tolerance. Numerous trial
sites listed this accession as susceptible to bronze birch borer
(Madison, WI; Waseca, MN; Ames, IA;
Fort Collins, CO; Chanhassen, MN;
Urbana, IL; and Absaraka, ND).Minor
pests included birch leaf miner and leaf disease. The Absaraka, ND and the Carrington, ND
trial sites conditionally recommended this accession dependent upon its degree
of borer resistance.
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Cornus macrophylla Ames 10178
Ten out of eighteen sites reported maintaining this accession through the
1-year trial period; and only one site located at Urbana, IL
reported maintaining it through the 5-year trial period; no sites have reported
maintaining it through the 10-year trial period. Average plant height was 1.16m with an
average plant spread of 1.39m after the 5-year trial period. This accession had severe winter injury/death
at all trial sites and dieback to the soil level. This accession is not adapted for areas in
the North Central states due to its lack of winter hardiness, but may work
well in USDA Plant Hardiness Zone 6b or warmer.
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Ligustrum
obtusifolium PI 477010
Twelve out of fourteen sites reported maintaining this accession through the
1-year trial period; ten sites reported maintaining it through the 5-year trial
period; and five sites located at Chanhassen, MN; Ames, IA; Manhattan, KS; Waseca, MN;
and Fort Collins, CO reported
maintaining it through the 10-year trial period. Plant loss was attributed to insufficient
cold hardiness at Carrington, ND; Absaraka, ND;
and Grand Rapids, MN with moderate
winter injury at New Franklin, MO and Chanhassen, MN. However, Chanhassen, MN
cited this accession as hardier than other privets. In addition, two trial sites (Manhattan and Urbana)
cited plant injury to drought. Average
plant height was 1.31m and 1.90m after the 5-year and 10-year trial periods,
respectively. Average plant spread was
1.48m and 2.24m after the 5-year and 10-year trial periods,
respectively. Plant habit was cited as
dense, compact, and spreading. Foliage
quality was clean and unsightly throughout the growing season with only minor
disease and insect problems. Leaf
senescence was generally late with little to no fall color. Flower profusion was rated as average and
lasted approximately 15 days during mid-June through early July. Fruit display was rated from dull to
showy. Fruit was persistent for
approximately 40-50 days during mid-August through mid-October. Although this accession lacks hardiness in
zones 3-4, it can serve as a reliable shrub in areas with sufficient moisture
in USDA Plant Hardiness Zones 4b and warmer.
Three sites recommended this accession due to its’ minimal care
(Fort Collins),
colorful fruit production (Manhattan),
and cold hardiness (Chanhassen). A
seedling from this accession with a particularly dense form was selected as Ames 25097 and
distributed in 1999 for additional evaluation in the NC7 Trials.
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Lonicera maackii
PI 477998
Twelve out of fourteen sites reported maintaining this accession through the
1-year period; nine sites reported maintaining it through the 5-year trial
period; and six sites located at Waseca, MN; Ames, IA; Chanhassen, MN; Absaraka, ND; Carrington, ND;
and Fort Collins, CO reported
maintaining it through the 10-year trial period. Winter injury was cited at Chanhassen, MN
and Grand Rapids, MN and winterkill
at Fairbanks, AK. Average plant height was 1.68m and 2.72m
after the 5-year and 10-year trial periods, respectively. Average plant spread was 1.72m and 3.10m
after the 5-year and 10-year trial periods, respectively. All sites rated the foliage quality as
clean or having only slight damage.
Only three sites reported fall color, ranging from dull yellows
observed at Carrington, ND and Absaraka, ND
to a reddish green at Grand
Rapids, MN. Fragrant flowers appearing in late May and
finishing in early June were rated as showy at Ames, IA and Chanhassen, MN. Red fruits that persisted from mid-August
to late July were rated as showy at Carrington, ND; Absaraka, ND;
and Chanhassen, MN. Both the Chanhassen and Ames trial sites
indicated this accession as a potential weed due to heavy seed
production. Birds will consume the
fruits, increasing the potential for invasiveness. The Absaraka, Carrington, and Fort Collins site
recommended this accession because of layered branching habit, minor pest
problems, low maintenance, red berries, and dense foliage, but noted that
it displayed little ornamental merit.
This accession will perform well with little maintenance and is
reliable in the Central and Southern Great
Plains. However, due
to the invasiveness of this species, it is recommended that other shrubs
should be used in its place.
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Pterostyrax
hispidus Ames
8079
Thirteen out of nineteen sites reported maintaining this accession through
the 1-year trial period; twelve sites reported maintaining it through the
5-year trial period; and only one site located at Waseca, MN
reported maintaining it through the 10-year trial period. winter injury was cited at Chanhassen, MN, Urbana, IL; Madison, WI;
and East Lansing, MI with winterkill
at Fort Collins, IL; Carrington, ND
and Absaraka, ND. Average plant height was 0.90m and 2.70m
after the 5-year and 10-year trial periods, respectively. Average plant spread was 0.71m and 2.05m
after the 5-year and 10-year trial periods, respectively. The Waseca, MN site commented on this accessions’
unusual bark. No additional comments or
data was received on this accession. No
sites recommended this accession because it is neither drought tolerant nor
cold hardy.
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Quercus phellos Ames 4723
Ten out of sixteen sites reported maintaining this accession through the
1-year trial period; seven sites reported maintaining it through the 5-year
trial period; and two sites located at Urbana, IL and Ames, IA
reported maintaining it through the 10-year trial period. This accession winterkilled at Fort Collins, CO; Carrington, ND;
and Manhattan, KS with severe
winter injury cited at Ames, IA and Urbana, IL. Average plant height was 2.38m and 4.40m
after the 5-year and 10-year trial periods, respectively. Average plant spread was 1.20m and 2.95m
after the 5-year and 10-year trial periods, respectively. Foliage quality was either rated as clean
all season or slightly damaged due to spider mites or leaf spot. Fall color was cited as a dull yellow
in Fort Collins, reddish brown in East Lansing, dull brown in Waseca, MN, and a
combination of orange, red, purple, and yellow at Urbana, IL. Both the Madison,
WI and Ames, IA
sites indicated chlorosis and would not recommend this accession due to its
intolerance to high soil pH.
Interestingly, one tree at Urbana, IL was much
hardier and more vigorous than the other two planted at that site. Only the Urbana site recommended this accession,
but that recommendation was most likely directed towards the single seedling
that was observed to be hardy, pH tolerant, and having variable fall
color. The remaining trial sites did
not recommend this accession due to chlorosis and a lack of cold hardiness. According to the Urbana, IL
site, its one seedling with ornamental merit is worth evaluating further.
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Quercus phellos Ames 4724
Ten out of thirteen sites reported
maintaining this accession through the 1-year trial period; five sites reported
maintaining it through the 5-year trial period; and two sites located at Ames, IA and Manhattan, KS
reported maintaining it through the 10-year trial period. This accession did not seem to perform well
at any site with each site reporting different problems, including winterkill
(Carrington, ND), unattractive greenish-brown fall color (East Lansing, MI),
chlorosis (Ames, IA), leaf scorch (Manhattan, KS), and drought susceptibility
(Urbana, IL and Manhattan, KS).Average plant height was 1.98m and 4.0m after
the 5-year and 10-year trial periods, respectively. Average plant spread was 1.18m and 1.80m after
the 5-year and 10-year trial periods, respectively. Foliage quality was rated as clean or with
slight damage at all sites except Manhattan, KS which cited
unsightly leaf damage resulting from severe leaf scorch. Ames, IA indicated
that emerging foliage was reddish.
Fall color was dull brown to green at all sites, except the Waseca,
MN site reporting a reddish fall color.
Cooperators either did not recommended this accession or
indicated that it was too early to make a recommendation. This accession and Ames 4723 did not perform exceptionally
well at any site, although either accession may be valuable as breeding
material. It is likely that this
species is not well adapted to the North Central states. However, other populations of willow oak
may prove worthy and exhibit greater ornamental characteristics.
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Rhus copallina PI
607437
Eight out
of ten sites reported maintaining this accession through the 1-year trial
period; four sites reported maintaining it through the 5-year trial period; and
three sites located at Urbana, IL; Ames, IA; and Fort Collins, CO reported
maintaining it through the 10-year trial period. Winterkill was cited at Fort Collins, CO; Absaraka, ND;
and Chanhassen, MN with severe
winter injury at Carrington, ND and moderate
winter injury to one year wood at Ames, IA and Urbana, IL. Additional plant injury included canker at
the Fort Collins
site. Average plant height was 1.40m
and 2.70m after the 5-year and 10-year trial periods, respectively. Average plant spread was 1.23m and 2.83m
after the 5-year and 10-year trial periods, respectively. All sites rated foliage quality as clean
throughout the growing season. Foliage
was cited as glossy with excellent reddish fall color at the Ames, New Franklin, Absaraka, and Urbana trial sites. Flowers were produced only at the Waseca,
MN trial site, which reported a few inflorescences on 10-year old specimens. This accession was recommended by the Ames, New Franklin, and Urbana site. This accession would serve as a good accent
plant, having glossy foliage with red fall color and should be reliable in
USDA Plant Hardiness Zones 5b or warmer.
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Rosa setigera PI
495616
Five out of five sites reported maintaining this accession through the
1-year trial period; four sites reported maintaining it through the 5-year
trial period; and two sites located at Fort Collins, CO and Ames, IA
reported maintaining it through the 10-year trial period. Minor leaf spots were cited at both Ames and Fort
Collins. Average
plant height was 1.20m and 1.50m after the 5-year and 10-year trial periods,
respectively. Average plant spread was
1.50m and 2.80m after the 5-year and 10-year trial periods, respectively. By the 10-year trial period, flower
profusion was rated as showy or average with flowers lasting for approximately
23 days during late June through mid-July.
Interestingly, Lincoln, NE did not report
any flowering up to the 5-year trial period.
The Fort Collins and Ames sites both
recommended this accession after the final evaluation. This accession tends to display a weedy
appearance during the first couple years of establishment, but is followed by
attractive flowers and an arching form once established. Even with little care, this accession is
durable and vigorous requiring a large growing space (1.5m x 2.8m). This accession may outgrow a
homeowner’s landscape, but may work well in commercial or large-scale
landscape plantings.
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Sorbaria sorbifolia
Ames 7778
Eighteen out of twenty sites
reported maintaining this accession through the 1-year trial period; sixteen sites
reported maintaining it through the 5-year trial period; and eleven sites
located at Waseca, MN; Cincinnati, OH; Absaraka, ND; Manhattan, KS; Fort Collins, CO;
Ames, IA; Carrington, ND; East
Lansing, MI; Chanhassen, MN; Bismarck, ND;
and Fairbanks, AK reported maintaining it
through the 10-year trial period. Winter
injury was cited at Chanhassen, MN and Fairbanks, AK
with winterkill reported at Cincinnati, OH and Grand Rapids, MN. However, the Fairbanks site noted that this accession
could be treated as a herbaceous perennial because re-growth occurs at the
soil level. Average plant height was 1.39m and 1.78m after
the 5-year and 10-year trial periods, respectively. Average plant spread was 1.68m and 2.46m
after the 5-year and 10-year trial periods, respectively. All sites rated the foliage quality
as clean except for three sites, which reported bronzing (Absaraka, ND), yellowing (Morris, MN),
and severe leaf rust (Manhattan, KS).Fall color at
all sites was generally yellow and dull, but at Carrington and Absaraka the
yellowish fall color was complemented by reddish buds. Large, dense, creamy panicles were rated as
showy by six out of ten sites and occurred during the month of July, lasting
for approximately 35-45 days.
The Fairbanks site noted that the
flowers from this accession were much larger than other Sorbaria grown
in Alaska. Fruit capsules formed by mid-August and
were persistent until next spring. The
Chanhassen site cited these seed heads as unattractive. Six sites recommended
this accession because of its showy flowers, low maintenance requirements,
and dense growth habit. The remaining
four sites noted this accession as invasive (Manhattan, KS and Ames, IA),
having a straggling appearance (Chanhassen, MN), or lacking
winter hardiness (Cincinnati, OH). Many plants
from northeastern Asia have short winter-rest requirements. We
speculate that losses at Cincinnati
may have resulted from hard freezes in late winter after the plants had
broken dormancy.
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Sorbus reducta Ames 8371
Only four out of twenty-one sites
reported maintaining this accession through the 1-year trial period, and no
trial sites had any plants remaining by the 5-year trial period. This accession failed to establish at all
trial sites because of numerous factors, including rabbits (East Lansing, MI),
winterkill (Ames, IA and New Franklin, MO), insects (Lincoln, NE), drought
(Manhattan, KS), and poor quality of plants at planting (Grand Rapids,
MN). Due to the low quality of
plants distributed, a performance summary for this accession will not be
posted. We cannot recommend this accession for the North Central states based
on insufficient evaluation data.
Syringa reticulata
subsp. pekinensis PI 478008
Fourteen out of seventeen sites reported
maintaining this accession through the 1-year trial period; seven sites
reported maintaining it through the 5-year trial period; and five sites located
at Carrington, ND; North Platte, NE; Absaraka, ND; Urbana, IL; and Chanhassen, MN
reported maintaining it through the 10-year trial period. Plant loss was attributed to winter injury
(Chanhassen, MN), winter kill (Grand Rapids, MN and Urbana, IL), and moderate
herbicide injury (Absaraka, ND).Although plant loss was attributed to
winterkill at two sites, this accession did establish in USDA Plant Hardiness
Zone 3b.Average plant height was 2.12m 3.86m after the 5-year and 10-year
trial periods, respectively. Average
plant spread was 2.01m and 3.28m after the 5-year and 10-year trial periods,
respectively. Foliage quality was rated
as clean to slight damage with fall color ranging from dull yellow to
yellow-green. Little to no fall color
was reported at Chanhassen, MN; Absaraka, ND;
and Carrington, ND. Plants at Absaraka, ND
remained green until frost occurred.
Floral profusion was rated showy at Carrington, ND; Absaraka, ND;
and Urbana, IL; while the
remaining sites rated flowering as average.
Large creamy-white panicles appeared during early to mid-June for
approximately 14 days. Fruit ripened
during mid-September through mid-October and was persistent for
approximately 200 days. All trial
sites rated the fruit display as average.
The Carrington, ND and East
Lansing, MI
sites described the bark as being showy and exfoliating. All five sites recommended this
accession after evaluating for 10 years.
This small tree received excellent comments and ratings and is
worth trying on a wide range of sites throughout the North Central
states.
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Viburnum lentago
Ames 2813
Thirteen out of fifteen sites reported maintaining this accession through the
1-year trial period; eleven sites reported maintaining it through the 5-year
trial period, and eight sites located at Waseca, MN; Cincinnati, OH; Chanhassen, MN; Fairbanks, AK; Absaraka, ND; Ames, IA; Urbana, IL;
and Carrington, ND reported
maintaining it through the 10-year trial period. Winterkill was cited at Chanhassen, MN
and Fairbanks, AK and winter
injury at Glencoe, IL. The Absaraka, ND, East
Lansing, MI,
and Chanhassen, MN sites reported
moderate leaf damage by powdery mildew and leaf spots, resulting in leaf
decline. Deer browsing was common at
the East Lansing and Cincinnati sites.
Average plant height was 1.58m and 2.46m after the 5-year and 10-year trial
periods, respectively. Average plant
spread was 1.04m and 1.88m after the 5-year and 10-year trial periods,
respectively. Foliage quality across the Midwest was variable, with
ratings of clean (Carrington, Cincinnati,
Fairbanks, and Ames), slight damage (Waseca and
Chanhassen), and unsightly (Absaraka).The Absaraka site rated this accession
unsightly because of severe powdery mildew.
Fall color was also variable in colors including reddish tones (Ames,
Absaraka, Carrington, and Urbana), purplish tones (Cincinnati
and Urbana), dark orange (Waseca), and little to no fall color
(Chanhassen and East Lansing).Flowering occurred during mid-May through
mid-June, lasting approximately 14 days. Flowers were rated as showy by the
Absaraka and Carrington sites, average by the Chanhassen and Fairbanks sites, and dull by the Ames site.
Ripening of fruit started in late July and persisted to
mid-September. Fruits were rated as
showy by the Waseca, Absaraka, and Carrington sites, average by the
Chanhassen site, and dull at the Fairbanks
and Ames
sites. This accession was recommended
by five out of eight trial sites that evaluated it for at least 10
years. Points in its favor include
probable hardiness to USDA Plant Hardiness Zone 2b, dark green, glossy
foliage, drought tolerance, reliable fall color, and attractive flowers and
fruits and wide adaptability throughout the North Central states.
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