University of Arkansas Plant Evaluation Program

2004 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 2004:

 

This completes the sixth 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 November 19; Fayetteville on November 16; and Hope on November 28.

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. Average plant size is 32” tall x 13” wide and a year-end growth index (GI) of 0.101 m3.

 

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.  No plants died at Little Rock even though the soil is very poor at that location. Average plant size (mostly Little Rock plants) is 41” tall x 12” wide and a year-end growth index (GI) of 0.089 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 and continued to flower until late November.  Cold fall temperatures caused the normally dark green foliage to turn a beautiful crimson. Average plant size is 14” tall x 16” wide and a year-end growth index (GI) of 0.050 m3.

 

Clethra tomentosa ‘Cottondale’

One gallon plants were initiated by cuttings at UofA from a Woodlanders Nursery plant.  In general, growth was good at all three locations.  Plants flowered well from late July until early September.  Average plant size is 35” tall x 20” wide and a year-end growth index (GI) of 0.194 m3.

 

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 is likely a result of using very small plants and not a result of adaptability to Arkansas summer conditions. Average plant size at Little Rock and Hope is 21” tall x 10” wide and a year-end growth index (GI) of 0.036 m3.

 

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.  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 24” tall x 44” wide and a year-end growth index (GI) of 1.245 m3. The surviving 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.  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. Average plant size at Little Rock and Hope is 8” tall x 7” wide and a year-end growth index (GI) of 0.006 m3.

 

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.  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. Average plant statewide is 17” tall x 6” wide and a year-end growth index (GI) of 0.015 m3.

 

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. Statewide, average shoot height is 71” tall with a trunk caliper measured at 39 inches of 0.6”

 

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.  All four plants died during the growing season at Hope.  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 at Little Rock and Fayetteville is 22” tall with a trunk caliper measured at 39 inches of 0.5”

 

 

 

 

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.