University of Arkansas Plant Evaluation Program
2004 Plants/ Arkansas Plant Evaluation Program
2006 Report
[Program information (data, reports, photographs) can be
found on the internet at: http://www.uark.edu/campus-resources/cotinus/arboretum_html/planteval.html]
January
2007
Plants initiated in Spring 2004 (3 years data):
This completes the eighth
year of the statewide plant evaluation program.
The current team of cooperators includes Dr. Jim Robbins, Dr. Jon
Lindstrom, and Manjula Carter.
The three test sites are the Hope
Research Center
(USDA cold hardiness zone 8), Little Rock
(zone 7a), and the Fayetteville Horticulture Research farm (zone 6b). As much as possible the three test sites were
prepared in a similar manner. Full sun
plants were grown in row-type beds 3’ wide with a 7’ grass alley. Plant groups are planted together (i.e. trees
are planted together). Trees are spaced
10’ apart, shrubs 6’ apart, and herbaceous perennials 4’ apart. The Little Rock
site was planted on March 19, 2004;
Fayetteville was planted on March 19, 2004; Hope planted on March 20, 2004. Irrigation at all three sites is by a drip
system. Plants were fertilized and
mulched after planting. Post-emergent
herbicides were used at all three test sites.
No disease or insect control was implemented during the first year. To
maintain a tree-like habit, trees are pruned following final growth
measurements. Pruning consists of removing
the bottom 1/3 of limbs. SHRUBS are NOT
pruned. Final growth measurements
were taken at Little Rock on
October 20; Fayetteville on October
31; and Hope on October 17.
Weather data at all three test
sites is attached (see attached graph).
Note: Significant losses
occurred with the 2004 planting. Several frosts and freezes occurred after
planting date and these weather occurrences had a significant, detrimental
effect on many of the plants as noted below.
Osmanthus americanus
One-gal plants were purchased from Pine Ridge Gardens, London, AR.
We were very impressed how well this plant grew statewide during the
first growing season. All 12 plants are alive. Significant flowering was noted
in 2006. The small white flowers
appeared in early April and mid-October. Average plant size is 52” tall x 40”
wide.
Styrax confusus
One-gal plants were
initiated by UofA from a Pine Ridge Nursery plant. Mortality for this plant was 100% at Fayetteville
due to an unexpectedly harsh early spring environment and Hope for some unknown
reason. One plant died at Little
Rock in 2005 even though the soil is very poor at that
location. The attractive white star-like
flowers develop in mid-May. Average plant size at Little
Rock and Hope is 81” tall x 36” wide and a year-end
growth index (GI) of .754 m3.
Viburnum obovatum ‘Christmas Star’ (received as ‘Riefler’s Dwarf’)
One-gal plants of were initiated by cuttings at UofA from Univ. of Georgia plants. All four plants died at Fayetteville
during the first growing season. Several
plants at Hope and Little Rock
began flowering in early September 2004 and continued to flower until late
November. Flowers begin to appear in
early April but significant flowering occurs in September through the first
hard freeze. Cold fall temperatures caused the normally dark green foliage to
turn a beautiful crimson. Average plant size is 27” tall x 39” wide. This broadleaf is very impressive at Little
Rock and Hope. It should be noted that other cultivars
of this species have survived in Fayetteville,
but tend to be deciduous during colder winters.
Clethra tomentosa ‘Cottondale’
One gallon plants
were initiated by cuttings at UofA from a Woodlanders Nursery plant. In general, growth is good at Hope and Little Rock. Two
of the four plants died at Fayetteville in the first year (2004) and two more died in 2006. Two of the four
plants died at Little Rock in 2005. Plants flowered well from late July until early September. Average plant size is 40” tall x 31”
wide. Plants at Hope (52”) are considerably
taller than plants at Little Rock
(28”).
Cleyera japonica
One gallon plants
were initiated by cuttings at UofA from Univ. of Georgia plants.
All four plants at Fayetteville died during the 2004 growing season. Mortality in the first year is likely
a result of using very small plants and not a result of adaptability to Arkansas summer conditions. By the end of 2006 only
two plants remain alive, and those are at Little Rock. Average plant size at Little Rock is 31” tall x 20” wide.
Indigofera heterantha
One quart plants
were initiated by cuttings at UofA from Univ. of Georgia plants. Mortality statewide was high with
eight of the 12 plants dying in the first growing season. The remaining plant died at Fayetteville in 2005. Mortality is likely a result of
using very small plants and not a result of adaptability to Arkansas summer conditions Surviving plants at Hope
and Little
Rock
flowered from early June until late September. Average plant size statewide is
54” tall x 97” wide. The plant was a favorite of rabbits in Fayetteville.
Buddleia loricata
One quart plants
were grown from seed obtained from Silverhill Seed in South Africa.
Mortality statewide was high with nine of the 12 plants dying in the
first growing season (2004). All four
plants at Fayetteville died during the 2004 growing season. Mortality is likely a result of using very
small plants and not a result of adaptability to Arkansas summer conditions. The remaining plants
statewide died during 2005. This species is one parent of the new hybrid B. ‘Silver
Anniversary’.(the other parent is B.
crispa)
Viburnum lantana ‘Mohican’
One gallon plants
were initiated by cuttings at UofA from Greenleaf Nursery plants. Three of the four plants at Fayetteville died during the first growing season. As of the fall of 2006 only one plant remains
at Hope. Mortality at Fayetteville and poor performance at Little Rock and Hope is likely a result of using very
small plants and not a result of adaptability to Arkansas summer conditions. Plant size at Hope is 20”
tall x 6” wide.
Tetradium (Evodia) daniellii
Two-gallon container plants were
donated by J. Frank Schmidt Nursery.
Survival and growth statewide was very good during the first year. One
plant died at Hope in 2005. All plants flowered at Fayetteville
in 2005 in late June and early July. Statewide, average shoot height is 120”
tall with a trunk caliper measured at 6 inches of 2.7”. Both flowers and
developing fruit provide ornamental interest.
Sequoiadendron giganteum
Bareroot liners were purchased from
Lawyers Nursery. Mortality was very high
statewide as indicated by the fact that 10 of the 12 plants were dead by
mid-summer of the first year (2004). All
four plants died during the growing season at Hope. Only one plant remains at Fayetteville.
The high mortality is likely a result of using small bareroot plants and not a
result of adaptability of this plant to grow in Arkansas. Average shoot height one the one remaining
tree growing at Fayetteville is 52” tall with a trunk caliper measured at 6
inches of 2.8”
The
Ornamentals team would like to express their sincere appreciation to the
cooperating nurseries (J. Frank Schmidt
Nurseries, Dr. Michael Dirr- University of Georgia)
for donating the plants for this season’s trial and to the Arkansas Green Industry Association for financial support.
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