Arkansas Plant Evaluation Program
2000 Plants/ Arkansas Plant Evaluation
Program2004 Final Report
[Program information
(data, reports, photographs) can be found on the internet at:
http://www.uark.edu/campus-resources/cotinus/arboretum_html/planteval.html]
2004
Final Report
January
2005
Plants initiated in Spring 2000:
The report concludes the 5-year evaluation
for this set of plants.
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), the Little Rock/Cammack property (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. Little Rock
site was planted on April 21, 2000;
Fayetteville was planted on April 27, 2000; Hope planted on April 20, 2000. Plants at all three sites are irrigated as
needed using drip tape. Plants were
fertilized and mulched after planting.
Post-emergent herbicides were used at all three test sites. No disease or insect control was implemented
in 2002. The Acer and Eucommia were
pruned following final growth measurements to establish a tree-like habit. Pruning consisted of removing the bottom 1/3
of limbs. Shrubs are NOT pruned.
Final growth measurements were taken at Little Rock
on November 19; Fayetteville on
November 16; and Hope on November 28.
Plants at the Little Rock
site do receive a few hours of shade generally during the morning hours. Fayetteville
and Hope are very exposed, full sun sites.
The Fayetteville site is
characterized by consistent winds.
Weather for 2004 at all three test
sites is summarized (see attached graph).
Rhaphiolepis indica Eleanor TaberTM
Flowerwood Nursery donated 3-gal plants. The winter of 00/01 proved to be a good test
for this plant. Both cultivars of Indian
hawthorn suffered severely at Fayetteville
(USDA zone 6b) and all are dead, but are growing
well at Hope and Little Rock. Peak flowering is typically in late April and
lasts for several weeks. Flower color is
a very soft pink. Flowers tend to be
nestled in the foliage more so than OliviaTM
. The blue-black fruit which is formed
in the fall is held on the plant until early spring. In contrast to OliviaTM ,
winter leaf color on Eleanor
TaberTM is green. Average plant size at Little
Rock and Hope is 34” tall by 66” wide. The habit on Eleanor TaberTM is tighter than on OliviaTM .
Rhaphiolepis indica OliviaTM
Flowerwood Nursery
donated 3-gal plants. Based on
mortality at Fayetteville (all
three OliviaTM dead; all 1999 planted Bay Breeze dead; one Eleanor
TaberTM alive) one might conclude that Eleanor TaberTM is
slightly more cold tolerant than OliviaTM and Bay BreezeTM.
Regardless, Rhaphiolepsis
are not suitable for use in Fayetteville.
Flowering period in Little
Rock was nearly identical to the above except that a
significant re-bloom was noted in August through September. Flower color is pure white. Leaves on OliviaTM
are distinctly different from Eleanor TaberTM. Leaves on OliviaTM are almost
round (rounded-ovate) and slightly coarser than Eleanor TaberTM. Average plant size at Little Rock and Hope
is 37” tall by 67” wide.
Ternstroemia gymnanthera Bronze BeautyTM
Flowerwood Nursery donated 3-gal plants. Again, the 00/01 winter was a great test
winter for broadleaf evergreens including Ternstroemia.
All three plants were killed at Fayetteville.
Plants at Little Rock
grew more upright while those at Hope grew more in a rounded habit. Plants displayed a beautiful burgundy color
in the outer most foliage in late fall.
Average plant size at Little Rock
is 125” tall by 73” wide.
Illicium parviflorum
One-gallon
plants were purchased from Pine Ridge Nursery, London,
AR.
This plant is a real dilemma for the program. Plants are growing very vertical and would
benefit from being severely cut back to encourage more branching, however,
protocol for the trial does not allow for intervention pruning except for
trees. We also feel that this plant
would benefit from at least partial shade in Arkansas.
All three plants died at Fayetteville
and two of the three have died at Hope. Remaining plants at Little
Rock and Hope are growing very well in year #4.
Flowers, which are obviously not showy, began to appear at Little
Rock in mid-June and continued sporadically for the
next 2 months. Average plant size in Little
Rock and Hope is 70” tall by 77” wide. Again, our
plants would have benefited from heading back the single central leader in the
first year but this is not allowed in our program.
Diervilla lonicera ‘Copper’
One-gallon plants were initiated at
UofA by cutting propagation from a plant purchased from Arborvillage, Holt,
MO. Plants
continue to grow well at all three sites, but 2004 was perhaps the worst
performance in Fayetteville.
Drought
in July and August caused premature defoliation on this cultivar. Flowering
Lonicera nitida ‘Ernest Wilson’
One-quart
plants originated from UofA cutting propagation from a plant purchased from
Wilkerson Mill Gardens, Palmetto, GA.
Growth rate was greatest at Little Rock
and least at Hope. Plants in Fayetteville
were killed to the ground during the 00-01 winter, but new growth emerged from
the base of the plant. Flowers were not
observed at any location in 2004. The
plant, with very small fine textured leaves, averages statewide 38” tall by 84”
wide. Plant habit looks very much like a
cranberry cotoneaster without the bright red fruits. Plant texture is very fine. Many plants
continue to lose leaves in the center of the plant resulting in a less than
desirable appearance. In general, we
still like this plant for use in warmer parts of Arkansas.
Viburnum awabuki ‘Chindo’
North Carolina State University donated
one-quart plants. Janet Carson had seen
this plant used extensively during a visit to Raleigh
in 1999. All nine plants were
surprisingly killed during the winter of 00/01.
Rhus aromatica ‘Gro-low’
Bailey Nursery
donated bare-root plants. Plants
continue to grow at a very rapid pace.
Due to a planting error on our part we had to move two plants from Hope
to Little Rock rather late in
2000. This procedure set two of the
three Little Rock plants back
severely, and contributed to the death of one plant. Average plant size statewide is 49” tall by
118” wide. Plants in Little
Rock and Fayetteville
flowered in early to mid April. Fall color is almost non-existent at Hope and
Little Rock. Again, we suspect
that, like Diervilla, better fall
color develops the further north this plant is used.
Viburnum
One-quart
plants originated from UofA cutting propagation from a plant purchased from
Wilkerson Mill Gardens, Palmetto, GA.
The plant was a recommendation by Ewa Nelson, Morningside Nursery. I have been impressed with its glossy
foliage, nice flower display, and tight plant habit.
All three plants died at Fayetteville
and two have died at Hope. However, it
should be noted that larger plants, not in the official trial, that are planted
on the Fayetteville campus did
survive the winter of 00/01. Flowering
began at Little Rock in early-April
and lasted for 2-3 weeks. Average plant
size at Little Rock and Hope is 49”
tall by 73” wide.
Viburnum בEmerald
Triumph’
Bailey Nursery donated bare-root plants. Cameron Rees of Skinner
Nursery, Topeka, KS
recommended this plant. Cameron spoke
highly of the dark green leaves and plant habit.
The plant is not proving to be a
winner at any of the three sites. Plant
habit is not as tight as expected and we have observed dieback possibly related
to our summer heat. Flowering began in Little Rock
on March 24 and in Fayetteville on March
30. In Little Rock, the flowers
Abelia
chinensis
One-gallon plants originated from UofA
cutting propagation. The source plant
was from Woodlanders Nursery, Aiken, SC. This species is one of the parents of Abelia
The flower display is very
noteworthy. The white or very soft pink
flowers appear in late June and continued through at least late August.
Attractive soft pink calyxes followed the flowers giving the impression that
the plant is still in bloom. This lasts
until a very hard freeze. It is hard to separate the overall effect of the flowers
and the pink calyx. Flowering began in Little Rock
on June 12 and continued for at least several months. In Fayetteville,
the plants had been killed to the ground during the winter of 00/01 but have
recovered nicely. Average plant size
statewide is 77” tall by 96” wide.
Acer
buergerianum
J. Frank Schmidt Nursery donated
one-gallon plants. All three plants died at Fayetteville
during 2001. Trees in Hope and Little
Rock grew exceptionally well. An unusual thing happened in Little
Rock in August 2002.
Some animal, probably squirrels, began feeding on the trunk and lateral
branch bark. In some cases the entire
trunk was girdled but the shoot showed no wilting symptoms. What is amazing is that in our random plots
the animal picked out every trident maple tree.
Average tree height at LR is 228”
(nearly 19’) with an average trunk caliper at 6” of 6.8”.
Eucommia
ulmoides
J. Frank Schmidt Nursery donated bare-root
trees (4-5’ BR). The tree is finally
starting to establish itself at LR and Fayetteville but
is struggling at Hope
The
Ornamentals team would like to express their sincere appreciation to the
cooperating nurseries (J. Frank Schmidt
Nursery, Bailey Nursery, and Flowerwood Nursery) for donating the plants
for this season’s trial and to the Arkansas
Green Industry Association for financial support.