Robert E. Lyons
Professor and Director
With Technical Assistance from Bernadette Clark and Sandra Cook
Department of Horticultural
JC Raulston Arboretum
Horticultural Research Series No. 147
The Annual Trial Gardens at NC State Univesity are located within the JC Raulston Arboretum, 4301 Beryl Road, in Raleigh. The JCRA is an 8 acre site administered by the Department of Horticultural Science and located on latitude 35° 47'N, longitude 78° 42'W with an elevation of 400 feet.
Seedling and vegetatively derived plants were grown to transplant size in 2.5 inch x 2.2 inch containers, with most planted outdoors on 25 April 2000. The remaining selections were planted when transplant survival was determined to be optimized. Plant spacing in the trials was 18 inches x 24 inches (in-row x between-row spacing). Seven plants of each entry were used to evaluate the performance of the cultivars. Plants were rated weekly as described later in this report.
We also gratefully acknowledge the support by Fafard, Inc. (P.O. Box 26, Anderson, SC 29622) and the North Carolina Commercial Flowers Growers Association. The assistance of Sandra Cook, Ingram McCall, Brad Holland, Paul Lineberger, Mitzi Hole, Valerie Tyson and Chris Glenn is acknowledged with much appreciation!
Robert E. Lyons (no longer at NC State University)
Professor and Director
Horticuture Research Technician
Total precipitation for the trial period May through October 2000, in Raleigh, North Carolina. The Historic Mean represents an average total precipitation from the years 1950 - 1995. No record of the June 2000 rainfall was available for comparison.
The average minimum and maximum temperatures for the trial months of May through September 2000, in Raleigh, North Carolina. The Historic Minima and Maxima represent the averages for these parameters from 1961 - 1990. No record of the June 2000 average temperatures were available for comparison.
We are reporting our results in a different way from what you've seen in the past. We hope this will provide even more useful information whether you are one of our grower/landscapers or one of our participating seed companies.
Plant Height & Diameter
This measurement is taken near the end of the evaluation period.
Number of Weeks in Flower
We have always recorded which weeks each variety is in flower, but we are now showing you the total number of weeks in flower. This will give you an idea of whether a plant is best used for the whole season or as a "fill-in" for special occasions. Obviously, those species grown for foliage interest alone will score poorly in this column!
Plants were given a visual rating weekly by the same person beginning May 16, 2000 (three weeks after planting) through September 25, 2000 (20 weeks of observations.) The rating was based on plant performance and appearance, including floriferousness, plant size and shape, and freedom from insect and disease problems. The rating scale ranged from 1 (very poor) to 5 (excellent), with 0.5 unit increments; a 0 rating indicated that all seven plants of the cultivar trial died.
Summaries of Weekly Ratings
In the past, we presented an "all season average" of the weekly ratings for each variety over the whole evaluation period and made our comments based on this statistic alone. Knowing that there are many species/cultivars which may do better in one part of the growing season than another, we now provide an "early season average" and "late season average" for each entry. The former is the average of the first eight weeks of the evaluation period and the latter includes only the last eight weeks. This information may be useful in planning short term plantings with high impact as well as for studying temperature preferences, life cycle changes, and/or the impact of photoperiod on plant performance. The "number of weeks rated above 3" gives you an idea of how consistently throughout the twenty weeks an entry is an exemplary performer.
The Lists In This Report
We list each of the above statistics (except the weekly ratings themselves) in all the reports that follow:
Our Web Site <www.ncsu.edu/jcraulstonarboretum>
Want additional copies of this report? Please feel free to print off what you need from our Web site!
In this section you'll find summarized comments from those we recorded throughout the growing season......kind of like a "between the lines" addition to the actual ratings found in this report. Our comments are in alphabetic order according to species and we did not list ALL of our species tested in our comments below.
This was a lovely plant early in the summer but flowering declined rapidly as the summer heat increased. By mid-summer, it had stopped flowering completely and never returned to its spring display qualities. For those interested in foliage, the plants maintained a very compact, bushy appearance in the absence of flowers and could conceivably be considered oranamental nonetheless!
The tropical butterflyweed species, Asclepias curassavica, was not formally included in our ratings since it was installed several weeks after the other species. However, its performance is worth noting. It was fast to grow and come into flower; once in flower, it stayed colorful all season, being an indeterminate type of milkweed that flowers from every node. We examined 'Red Butterflies' and 'Silky Gold' and were impressed with both.
Our best traditional wax begonia at the end of the season was 'Inferno Red' but we are very excited about the the hybrid 'Dragon Wing' which also excelled.....somewhat taller than most wax-types, it remains compact, strong, well-flowered, and elegant with its lovely foliage. Having the flowers more pendulous than most gave a great display.
This was a real surprise. The performance of 'Cosmic Orange' was anything but predictable. Although it was indeed much more compact, its flowering period was undesireably abbreviated at best, virtually gone by midseason. Cosmos may be true annuals, but they should last much longer than 'Cosmic' did in order to become adopted by our region's gardeners.
Here's a novel foliage plant whose variegated foliage and rapid growth add great background and interest to other colors. Be sure to pinch it at planting; it flourished without growing too aggressively. With the growing interest in tender perennials, this plant deserves more attention by growers, designers, and landscapers.
These don't often perform exceptionally well in the Raleigh area and this year exemplified this for the worse. The rainy weather contributed to an overall dismal showing with the exception of these standouts amidst the dreary crowd: 'Fantasia Flame' and 'Salmon Compact Cascade'. As series, the Fantasia and Designer series were the best.
These should become great garden plants and 'Florabella Lemon' proved to be outstanding all season as it was in full flower.
What a year for New Guinea impatiens, at least most of them! When viewed individually, there were many outstanding entries, including 'Ovation Hot Lava' (what a great name!), 'Harmony Raspberry Cream' and 'Alexis'. Flowers were prolific, large, highly visible and lasting, and foliage/flower contrasts excellent. However, when viewed from a distance, clearly one drew the vast majority of attention.
The classic impatiens performed beautifully this year and a few entries surpassed the others......we liked the series 'Dazzler', 'Carnival', and 'Showstopper'. This was a good year to really evaluate the progress made with the doubles, or so called "rose bud" impatiens. Known in the past for slower growth and less vigorous flowering, doubles have come a long way; we found 'Fiesta White' as well as the entire 'Fiesta' and 'Tioga' series to be standouts and highly recommendable.
We hope that improvement continues with these plants to exploit their true potential. We noticed some variability in plant size, but their ability to attract butterflies was proven this summer. Our best were 'Star Lavendar Light', 'Butterfly Cherry Red' and 'Star White'.....it is unfortunate that the latter cultivar shares its name with a Ziinnia angustifolia!
Many cultivars in our trials faired poorly after many days of rainy and cloudy weather late in the season, never recovering up to par. However, the Wave series, 'Marco Polo', and 'Happy Dreams' were the best of the lot to endure this unusual Raleigh late summer, often returning to full form shortly after getting the pounding from the rain. The cultivars of Petunia integrifolia, 'Laura Bush' and 'VIP', displayed tons of flowers, exhibited good rainfall recovery, and vivid reddish coloration throughout most of the summer. The Liricashower and Million Bells types went down as soon as the weather turned nasty, appearing with virtually no flowers for the last half of the summer.
It is terrific to see plants that were relegated only to conservatories making their way into the landscape. Plumbagos are a great example. Although they grew slowly at first, waiting for the warm weather to persist, they flowered almost continuously until the end of the trial period.....we examined 'Escapade Blue' and 'Escapade White' at our site.
The blackeye Susans were quite variable, doing much better in the first half of the season and faltering later on. Our comparisons included the native North American species; itself a wonderful addition to any sunny garden. The star of the group was clearly 'Indian Summer', a past All American Selection Winner and well worth further use by the landscape profession. This cultivar maintained its high ratings from start to finish, outpacing its cousin cultivars which could not retain their strong performance.None of the rudbeckias were spared the late season bout with powdery mildew,unfortunately, but the incidence came late enough in the season so as to be inconsequential to the performance, except maybe to the purist. These plants were visitor favorites.
The best of the Salvia splendens group was 'Red Hot Sally' with its strong lasting qualities and bright coloration. The 'Strata' cultivar from the Salvia farinacea group rose above the rest with its sturdy habit, blemish free leaves, and full flowered spikes which lasted very long into the season. This one's been around for a while and it is easy to see why!
This plant was initially dubbed the "Bed of Nails" plant by us. Its broad and large green leaves were pegged on both sides with numerous, sharp spines along the purple veins. The plant grew very fast. Installed with only 3-4 leaves, it rapidly achieved 4' in height and possessed a dense, almost impenetrable canopy. Quite ornamental during the season in its own right, it also developed furry tomato-like fruits along its stems that turned yellow-orange in late summer. Intriguing and easily grown from seed. Could easily be an "annual barrier" plant.
The heightened interest in this plant proved true during our trials. No matter what the cultivar, visitors found them to be fascinating and attractive, especially knowing that the subsequent seed heads made great food for birds......now if we could only get their flowers to last longer! The double rotation worked well in our growing season, at least one way to deal with the relatively short flowering display. The best of the "branching" types were 'Henri Wilde', 'Vanilla Ice', 'Sundown', 'Chianti', and the newest one called 'Ring of Fire'. The single stem types that outdid the others were 'Ikarus', 'Elite Sun', and 'Lemon Queen'.
Mexican sunflower is one of my favorite plants but this summer's humidity and intermittent late rainfall became its downfall. It crashed and burned in this weather, becoming tired, shriveled, and necrotic by midseason and could not continue flowering up until frost, as it should. 'Fiesta del Sol' is a vast improvement for shorter size and compactness over the older cultivars but still couldn't maintain its floriferousness and beauty throughout the season.
Unlike last year when they flourished in the hot, dry season, almost all of those examined in 2000 flowered poorly and sporadically. A major exception this year was the 'Aztec' series which was truly excellent all season.
Most of our vincas proved to be excellent with the 'Cooler' series and the cultivar 'Pacifica Red' being standouts. However, we'd like to post our first warning flag over the cultivars having light green foliage. Eventhough their overall performance was excellent, virtually all visitors assumed they were "sickly chlorotic" and nutrient deficient......a clever marketing scheme better accompany these releases if they are to be understood and adopted by consumers!
So far, it appears that violas are still better grown and marketed for winter color in the Raleigh area.....their summer performance was indifferent.
We are big fans of the "Profusion" series as they are hugely more resistant to powdery mildew than their Zinnia elegans cousins. Their incredibly compact habit and densely flowered behavior sets them apart from most. However, 'Profusion Cherry' once again exhibited faded flower colors and "splitting" in the latter half of the season. These unfortunate features were NOT characteristic of the white and orange cultivars which excelled. Another interesting historical surprise was the stellar performance of the old favorite called the "Old Mexico" zinnia (Zinnia haageana); maybe not the most compact of habits, but a solid performer nonetheless!