December 11, 2000 (.pdf file, requires Adobe Acrobat)

The current team of cooperators includes Dr. Jim Robbins, Dr. Jon Lindstrom, Dr. Gerald Klingaman, Scott Starr, Dr. James Cole, Manjula Carter, Matthew Pelto, and Janet Carson.

The three test sites are the Hope Research Center (USDA cold hardiness zone 8a), the Little Rock/Cammack property (zone 7a), and the Fayetteville Horticulture Research farm (zone 6 b). 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. Plants 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 2000. 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. Final growth measurements were taken at Little Rock on November 2; Fayetteville on October 19; and Hope on November 30.

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.

Arkansas experienced above a very hot and dry summer (see graph). The average high temperature in Little Rock was 12 degrees above normal in August. The intense summer heat was followed by a ‘stock market’ like crash. In November, the average temperature was 6.7 degrees below the normal in Fayetteville. Insufficient cold temperatures prior to the onset of the early fall will likely damage certain plants such as Viburnum awabuki ‘Chindo’ which likely did not adequately harden. At the writing of this report it looks as though Arkansas will have a good ‘test’ winter this year!

Rhaphiolepis indica Eleanor Taber™

Flowerwood Nursery donated 3-gal plants. Plants are performing well at all 3 locations. The most significant increase in growth was observed at Little Rock. Fayetteville plants had the least growth. A small number of flowers were recorded toward the middle to late June. Average plant size is 14" tall by 23" wide.

Rhaphiolepis indica Olivia™

Flowerwood Nursery donated 3-gal plants. Plants are performing well at all 3 locations. Olivia did not grow as much as Eleanor Taber even though plants were similar in size when planted. Flowers were not observed. Leaves on 'Olivia' are distinctly different from 'Eleanor Taber'. Leaves on 'Olivia' are almost round (rounded-ovate) and slightly coarser than Eleanor Taber. Average plant size is 13" by 20" tall.

Ternstroemia gymnanthera Bronze Beauty™

Flowerwood Nursery donated 3-gal plants. Performance appears to be good at all three sites. The most significant increase in growth was observed at Little Rock. Plants at Hope grew approximately one-half that rate, and Fayetteville plants 1/10^th. Flowers were not observed at any location. Fayetteville reported yellowing of new growth as if affected by sun. Plants displayed a beautiful burgundy color in the outer most foliage in late fall. Average plant size is 27" by 31".

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. The most significant increase in growth was at Little Rock. Considerably less growth was measured at Hope and Fayetteville. Our interpretation at this point is that the intense full sun exposed sites at Hope and Fayetteville is less than ideal for this plant. Insignificant flowers began to appear at Little Rock and Fayetteville in mid-June and continued sporadically for the next 2 months. Average plant size is 34" tall by 14" wide.

Diervilla lonicera ‘Copper’

One-gallon plants were initiated at U of A by cutting propagation from a plant purchased form Arborvillage, Holt, MO. The most significant increase in growth was Little Rock, followed by Fayetteville, and then Hope. Some type of foliar spotting was observed in Little Rock, and one plant died in Hope. Flowering began in early June and continued for about one month. Rebloom was noted in July. The plant at this point is a low, spreading plant. At least in Little Rock the plant has a rather unkempt look. Average plant size is 15" tall by 39" wide.

Lonicera nitida ‘Ernest Wilson’

One quart plants originated from U of A cutting propagation from a plant purchased from Wilkerson Mill Gardens, Palmetto, GA. Growth rate was about equal at Little Rock and Fayetteville. Plants did not perform well at Hope. Flowers were not observed at any location in 2000. The plant, with very small fine textured leaves, averages 14" tall by 28" wide.

Viburnum awabuki ‘Chindo’

One quart plants were donated by North Carolina State University. Janet Carson had seen this plant used extensively during a visit to Raleigh in 1999. The most significant increase in growth was observed at Little Rock. Far less, and almost equal growth, was observed at Hope and Fayetteville. Fleshy, almost tropical looking new growth was easily damaged by early frosts at Hope and Fayetteville. It will be interesting to see if this plant survives the winter. Average plant size is 13" tall by 11" wide.

Rhus aromatica 'Gro-low'

Bare-root plants were donated by Bailey Nursery. Plants demonstrated a substantial increase in size in 2000. The most significant increase in size was at Hope, followed by Fayetteville, and finally Little Rock. Due to a planting error on our part we had to move 2 plants from Hope to Little Rock rather late. This procedure set 2 or the 3 Little Rock plants back severely, and contributed to the death of one plant. Flowers were not observed at any location. Average plant size is 25" tall by 55" wide.

Viburnum x 'Conoy'

One quart plants originated from U of A 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. Dr. Lindstrom in Fayetteville indicates one of its parents, Viburnum utile is performing better so we plan to include that plant in the 2001 planting.

Plants had moderate growth at Fayetteville and Little Rock. Plant grew even slower at Hope. Flowers were not observed in 2000. Average plant size is 12" tall by 16" wide.

Viburnum x 'Emerald Triumph'

Bareroot plants were donated by Bailey Nursery. This plant was recommended by Cameron Rees of Skinner Nursery, Topeka, KS. Cameron spoke highly of the dark green leaves and plant habit.

Plant growth was best in Fayetteville followed by Little Rock and the least growth in Hope. One plant died in Hope for some unknown reason. Flowers were not observed in 2000. The plant is more upright at this point than spreading. Average plant size in 30" tall by 23" wide.

Abelia chinensis

One gallon plants originated from U of A cutting propagation. The source plant was from Woodlanders Nursery, Aiken, SC. This species is the deciduous parent of Abelia x grandiflora. Plants grew exceptionally well at Fayetteville and Little Rock for the first year. Plants at Hope grew about 1/3 that of the other two sites. The flower display was very noteworthy. The white or very soft pink flowers appeared in late June and continued through at least late August. Flowers were followed by very attractive soft pink calyxes that gave the impression that the plant was still in flower. This lasted until a very hard freeze. Based on observations of plants at other locations, this plant can ‘throw’ aggressive shoots that make the plant look ‘wild’. So far our plants have stayed rather tight and not displayed this attribute. Average plant size is 28" tall by 29" wide.

Acer buergerianum

One-gallon plants were donated by J. Frank Schmidt Nursery. Plants at Little Rock grew 2-3 times as much as those at the Hope or Fayetteville location.

Eucommia ulmoides

Bareroot trees (4-5’ BR) were donated by J. Frank Schmidt Nursery. This tree has struggled statewide. Part of the problem may be related to the size of the bareroot trees received and our late date for planting. Based on experience with bareroot plants (Viburnum x 'Emerald Triumph') we suggest potting BR plants up into containers or placing in the field much earlier in the season. Dieback was noted at all three locations and one tree died at Hope.

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