[Program information (data, reports, photographs) can be found on the internet at: http://www.uark.edu/campus-resources/cotinus/arboretum_html/planteval.html]

This completes the fourth year of the statewide plant evaluation program. The current team of cooperators includes Dr. Jim Robbins, Dr. Jon Lindstrom, Manjula Carter, and Dr. James Cole.

The three test sites are the Hope Research Center (USDA cold hardiness zone 8a), the Little Rock/Cooperative Extension Service 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. Plants 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 23, 2001; Fayetteville was planted on March 23, 2001; Hope planted on March 22, 2001. 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 18; Fayetteville on October 24; and Hope on October 17.

Weather data at all three test sites is attached (see attached graph). I would summarize 2002 as follows: March cooler than normal (temperatures dropped to zero in Fayetteville for the first time in the trial); June/July/August reasonable rainfall and below normal temperatures; September very warm and extremely dry. October and November were significantly below normal in Fayetteville both in temperature and rainfall.

Flowerwood Nursery donated 3-gal plants. Performance appears to be good at Hope and Little Rock but not Fayetteville. Flowers were first noted in early May and continued for about 2 weeks at Little Rock and Hope. Flowering occurred in June in Fayetteville. Average plant size statewide is 24" tall by 30" wide.

Flowerwood Nursery donated 1-gal plants. All plants are dead statewide. Little Rock lost two of the three plants this year. Hope lost all plants this summer also.

J. Frank Schmidt Nursery donated 4’ BR plants. So far, the plant is performing poorly at all three locations. Habit is more like a crabapple and foliage is thin.

University of Arkansas propagated plants and they were planted from a 1-quart container. Seven of the nine original plants are now dead. The oak-like foliage is very attractive. Emerging foliage is a beautiful copper color.

University of Arkansas propagated plants and they were planted from a 1-quart container. Like the other Itea, plants are struggling at Hope. All plants in Fayetteville are dead. The plants in LR flowered from May 8 to the 23^rd. Flowers are actually quite impressive. The white spikes are shorter than Itea virginica but still showy. Average size in LR is 26" tall x 30" wide.

Crataegus species

University of Arkansas seed-propagated plants from a stock plant at Blossomberry Nursery in Clarksville, AR. This plant is from a 1970’s distribution from the U.S. National Arboretum. At this time we have no further information on its identity. Trees were planted as a 1-gal container plant.

The plant continues to grow very well at all three sites. Trunk diameter increased by slightly more than 1" statewide. Plants did not flower at LR, Hope or Fayetteville.

J.Frank Schmidt Nursery donated 3’ BR whips. Trees are growing well at all three test sites. Fall color was almost non-existent at all three sites. Some large acorns were noted at Fayetteville. In size they resemble the English oak parent. Although powdery mildew appeared in Fayetteville, it was 95% less than fastigiate English oak.

University of Arkansas propagated plants and they were planted from a 1-quart container. Sadly, all three test plants were stolen from the Little Rock site when this plant was in full flower.

We are still very impressed with the length of flowering on this shrub. Plants at Hope starting flowering on April 30 and were still blooming on November 9. Due to the fact the three plants were stolen in Little Rock and some over-ambitious Roundup spraying in Fayetteville, we will be re-evaluating this plant in 2003.

Average plant size at Hope is 42" tall by 40" wide.

University of Arkansas propagated plants and they were planted from a 1-quart container. Performance was good at all three sites. The shrub did not flower at Hope or LR in 2002. Plants flowered in Fayetteville in April. Average plant size was 17" tall by 39" wide.

University of Arkansas propagated plants and they were planted from a 1-quart container. Growth rate is unbelievable at all three sites. Plants at Hope, LR and Fayetteville flowered from mid-April to the first week of May. Flowers are not showy. Average plant size was 86" tall by 85" wide. This plant might make a good screen but the amount of seed produced is of some concern.

The Botany Shop, Joplin, MO, donated 1-gal plants. Performance was outstanding at all three sites. Average plant size was 56" tall by 30" wide. Plants doubled in height since last year.

J. Frank Schmidt Nursery donated 7’ BR whips. Growth was fair at all three sites. Foliage at all three sites was less than attractive. Leaves were dotted with what appeared as a leaf spot. Foliage that developed later in the season displayed less of this leaf distortion. Plants exhibited no fall color. Trees at Hope and FV increased in height by 30" and trunk caliper increased by 0.8".

Cotinus obovatus

J.Frank Schmidt Nursery donated 1-gal plants. All but one of the American smoketrees are dead. It would appear that our intense summer heat is too hard on this outstanding plant when grown in full sun.

One quart plants were purchased from Colvos Creek Nursery, WA. Plants are performing poorly in Little Rock and Hope. Plants in Fayetteville are multiplying nicely and began flowering in late June. Plants at Hope and LR begin flowering the second week of June and flower for at least one month.

The Ornamentals team would like to express their sincere appreciation to the cooperating nurseries (Flowerwood Nurseries, J. Frank Schmidt Nursery, and The Botany Shop) for donating the plants for this season’s trial and to the Arkansas Green Industry Association for financial support.

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