University of Arkansas Plant Evaluation Program
2007 Final Report
Plants initiated in Spring 2007 (4 years data):
This completes the thirteenth year of the statewide plant evaluation program. The current team of cooperators includes Dr. Jim Robbins, Dr. Jon Lindstrom and Qingfang Chen.
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 April 6, 2007; Fayetteville was planted on May 17, 2007; Hope planted on April 17, 2007. 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 one-third of limbs. SHRUBS are NOT pruned. Final growth measurements were taken at Little Rock on October 1; Fayetteville on October 10; and Hope on September 28.
|Rating||(growth after 4 years)|
|Buddleja 'Orange Sceptor||5||-||-|
|Rhaphiolepis indica Calisto™, 'Sodark'||4||9||17|
|Loropetalum chinensis Purple Diamond™||18||31|
|Loropetalum chinensis Purple Pixie™||10||20|
CJ = cannot judge due to insufficient information or other reasons
1 = Plant has performed well statewide
2 = Plant has performed well in zones 7a and 8.
3 = Plant performed fair statewide
4 = Plant performed fair zones 7a & 8
5 = Plant not recommended
6 = Plant performed well in 6b, poor in 7a & 8
7 = Plant performed fair in 6b, poor in 7a & 8
One-pint plants were initiated from cuttings from a plant purchased from Forestfarm Nursery. Three of the four plants growing at Little Rock died during the first growing season, and the sole remaining plant died in 2008. All four plants died in Fayetteville in 2008. Average plant size at Hope is 6" tall by 18" wide and a year-end growth index (GI) of 0.029 m3. Flowering begins in April and continues sporadically through fall. So far, the plant is performing fair in zone 8 (4).
One-quart plants were initiated by U of A from seed collected off a stock plant at Pine Ridge Gardens Nursery in London, Ark. There was minimal loss during the first growing season: one plant at Hope and one plant at Little Rock died during the first year. Plants did flower in early May at Hope. Average plant size is 93" tall with a trunk caliper of 2.7." The glossy black fruits are very attractive starting in September. Although the plants flower in Fayetteville, no fruit has been produced. Overall the plant is doing well statewide (1).
One-pint container plants were initiated from breeding lines developed by Dr. Lindstrom at the University of Arkansas. There was no plant loss during the first growing season; however, two plants died at Hope, and one plant died at Little Rock in 2008. By the end of 2009, there was only one plant remaining at each test site. All 12 plants had died by the end of 2010 (fourth year). Plants flowered during the first growing season. The plant is best suited for container use.
One-pint container plants were initiated from breeding lines developed by Dr. Lindstrom at the University of Arkansas. Mortality was very high during the first and second growing seasons at Hope and Little Rock. All plants were dead at those two locations within the first two years. Only one plant remains at Fayetteville. Average plant size at Fayetteville on the sole remaining plant is 32" tall by 50" wide and a year-end growth index (GI) of 1.050 m3. Overall, the plant has done well in 6b and poor in 7a & 8 (6).
One-gallon plants were initiated from rooted cuttings donated by Dr. David Creech at Stephin F. Austin Arboretum. All plants survived the first growing season. One plant died at Hope in 2009 and one plant died at Fayetteville in 2010. Average shoot height is 91" with a trunk caliper (at 6") of 2.7". Plant habit appears to be wider than T. distichum. Overall, plant performance is good statewide (1).
Three-gallon plants were donated by Flowerwood Nursery. No plants died statewide during the first growing season; however, all four plants died over the first winter in Fayetteville. Two plants died at Hope in 2010, as well as one plant at Little Rock. Average plant size at Hope and Little Rock is 9" tall by 17" wide and a year-end growth index (GI) of 0.045 m3 (essentially no size increase since 2008). Compared to other Rhaphiolepis we have evaluated, this plant is not performing very well. Performance overall has been fair in zones 7a and 8 (4).
One-gallon plants were donated by Flowerwood Nursery. Only one plant died (Hope) statewide during the first growing season, but the remaining three died at Hope during the second growing season. Three plants died at Fayetteville during the second year (2008) and the final plant died in 2010. These results mirror (poor performance in zone 8: Hope) what we observed for Loropetalum Plum Delight® which was evaluated in the 1999 program. Average plant size at Little Rock is 18" tall by 31" wide and a year-end growth index (GI) of 0.303 m3. Performance has been very good in Little Rock. Purple Diamond is clearly the larger of the two dwarf selections but is also substantially smaller than Plum Delight.
One-gallon plants were donated by Flowerwood Nursery. First-year mortality was higher with this cultivar. Three plants died at Hope and one at Little Rock. The sole remaining plant at Hope died in 2008. All plants at Fayetteville died in 2008. Average plant size on the two remaining plants at Little Rock is 10" tall by 20" wide and a year-end growth index (GI) of 0.052 m3. Performance has been good in Little Rock.
The Ornamentals team would like to express their sincere appreciation to Dr. David Creech, Stephen F. Austin Arboretum, and Flowerwood Nursery for donating the plants for this season’s trial.