Circular 326
Alabama Agricultural Experiment Station
John Jensen,
Interim Director
Auburn University
Auburn, Alabama
January 2004
| J. Raymond Kessler, Jr., Jon Coleman, and Arnold Caylor |
TABLE OF CONTENTS
Table 1, Performance Ratings by Species
The authors gratefully acknowledge the substantial donations of potting mix from Fafaard, Inc. and seeds from Ball, Benary, Goldsmith, Grimes, Pan American, Sakata, and Sygenta Seed Companies and plants from Bates Sons and Daughters and Lake Brantley Plant Corp as well as the time and efforts of Jon Coleman at Auburn and Arnold Caylor and his crew at the North Alabama Horticultural Substation.
Bedding plant growers frequently choose cultivars based on pack performance and adaptability to their production conditions. Garden performance of these selected cultivars within the marketing region is also an important factor in customer satisfaction and repeat sales. However, information on garden performance of bedding plant cultivars for Alabama may be difficult to obtain. Further, growing conditions vary widely from north to south within the state.
Therefore, in the summer of 2003, 185 bedding plant cultivars were evaluated on the Auburn University campus in Auburn, Alabama and 165 bedding plant cultivars were evaluated on the North Alabama Horticultural Substation in Cullman, Alabama. The objective of this study was to determine overall garden performance of summer-flowering annual plant cultivars (bedding plants) at a northerly and southerly location in the state. Results generated from this study will assist Alabama horticultural professionals and consumers in bedding plant selection. However, landscape performance may vary from year to year as climatic conditions affect performance.
METHODS
Seeds and plants for the trial entries were donated by several companies. Seeds were germinated in open flats and transplanted into 606 market flats at the Auburn University, Department of Horticulture, Paterson Greenhouse Facility. Caladium tubers and rooted liners of coleus were planted into 4-inch pots. Fafard 3B potting mix was used in all containers.
Raised beds were prepared by tilling at both locations and the soil was amended and mulched with 3 inches of “amendment grade” (fine) aged pine bark. All beds were located in full sun. A commercially available fertilizer and dolomitic limestone were pre-plant incorporated into the beds based on soil test recommendations. No additional fertilizer was applied during the season at Auburn, but several applications of liquid fertilizer were applied at Cullman. A preemergent herbicide, Pendulum 2G, was applied at 2.3 pounds per 1,000 square feet. Rainfall was supplemented using overhead sprinkler irrigation at Auburn and drip irrigation at Cullman to provide an equivalent of one inch of water per week. No deadheading of spent flowers or other maintenance was performed on any of the plants with the exception of hand weeding and Roundup herbicide applications between the beds. No pesticides were applied during the trial. Transplants were planted in early June at Auburn and in mid June at Cullman.
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Each bedding plant entry was randomly planted in 3 replications of
1-4 plants (depending on expected plant size) in a rectangle block
occupying half the bed width (2 feet). The beds were 4 feet wide and
each plant block occupied 2 linear feet of bed space. Therefore, each
replication was 2 feet by 2 feet (Figure 1). Each of the replications for each plant entry were evaluated every two weeks from July 18 to October 6 at Auburn and July 11 to October 2 at Cullman. Plants were rated by the same individual at each locations using a 1 to 5 scale. Flowering plants were rated primarily on their floral displays, while size, shape, and freedom from insect or disease blemishes were also considered. A rating of 1 indicated a small |
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RESULTS
Average performance ratings for all bedding plant species tested at Auburn and Cullman is in Table 1. The best performing bedding plant species in the “a” category at Auburn was Alternanthera (calico plant) and in the “b” category Spilanthes and coleus. All the coleus cultivars in this trial were full sun types from the Florida Sun Series. In the “c” category was petunia and dragon wing begonia and in the “d” category was ornamental pepper and vinca. All the remaining species receiving performance rating of 2.5 or higher would be suitable for the southern part of the state based on this trial. In contrast at Cullman, coleus and caladium were in the “a” category, while only pennisetum was in the “b” category. In the “c” category was Iresine (bloodleaf), celosia and basil and in the “d” category was marigold and portulaca. Seventy-seven percent of species rated 2.5 or higher at Cullman while only 47% rated 2.5 or higher at Auburn.
Average performance rating for bedding plant species tested while useful, does not provide a complete picture of performance through the season. The charts at the end of this document depict the average performance rating of bedding plant species for the two locations at each evaluation date. At Auburn, many bedding plant species increased in performance rating up to about the middle of August and then rapidly declined. These species could be effectively used in the landscape for the first part of the summer but would need to be replaced in late summer or early fall. In contrast, other species increased in performance rating and maintained good performance until the end of the trial. These included Alternanthera, dragon wing begonia, ornamental pepper, vinca, wax begonia, coleus, lavender, pentas, Spilanthes and Thunbergia. A few species at Auburn did not show good performance for the duration of the trial, particularly Anathemum, Centaurea, coreopsis, Dichondra, sunflower, and Silene. The patterns of performance over time observed at Auburn were not as apparent at Cullman. Species that performed well at Cullman generally maintained high performance ratings for the duration of the trial while those that performed less well only showed slow declines such as Dichondra and Silene. This, along with the data from table 1, illustrates the differences in climate and that many bedding plants may not be as well suited to the southern parts of the state.
The average performance rating for all bedding plant cultivars tested at Auburn and Cullman is in Table 2. The best performing entry at Auburn was Alternanthera with an average performance rating of 5.0. Petunia ‘Explorer Rose Pink’ can in second with a rating of 4.5 while petunia ‘Tidal Wave Cherry’ came in third with a rating of 4.4. Fourth place was shared by petunia ‘Explorer Lavender’ and ‘Explorer Magenta’ and coleus ‘Yulee’ with ratings of 4.3 while fifth place was shared by petunia ‘Explorer Pink’ and coleus ‘Elters’, ‘Saphoppy’, and ‘Astatula’ with ratings of 4.2. Fifth place belonged to petunia ‘Explorer Blue’ and ‘Wave Misty Lilac’ with ratings of 4.0 while petunia ‘Tidal Wave Purple’ and vinca ‘Sunstorm White e/Eye’ shared sixth place with ratings of 3.9. Seventh place was crowded with petunia ‘Ramblin Lilac Glow’ and ‘Wave Purple’, coleus ‘Micanopy’ and ‘Wimauma’ and vinca ‘Cooler Coconut Improved’ with ratings of 3.8. Eighth place was shared by petunia ‘Ramblin Violet’ and ‘Wave Rose’ and begonia ‘Harmony Scarlet’ with ratings of 3.7. Coleus ‘Altoonia’, ‘Bokcelia’ and ‘Chipola’, petunia ‘Ramblin Peach Glow’ and begonia ‘Dragon Wing Pink’ shared ninth place with ratings of 3.6 while begonia ‘Dragon Wing Pink’ and ‘Victory Bronze Leaf Rose Bicolor’, petunia ‘Ramblin Lavender’ and pepper ‘Chilly Chili’ shared tenth place with ratings of 3.5.
The best performing entries at Cullman were all coleus including ‘Chipola’, ‘Elters’, ‘Saphoppy’ and ‘Wauchula’ with performance ratings of 4.8. Second place was shared by coleus ‘Apopka’, ‘Astatula’, ‘Gotha’, Micanopy’, ‘Wimauma’, ‘Yalaha’ and ‘Yulee, caladium ‘Blizzard Bliz’ and ‘Florida Sweetheart’ and celosia ‘New Look’ with ratings of 4.7. Third place belonged to caladium ‘Florida Elise’, ‘Red Ruffles’ and ‘White Ruffles’ with ratings of 4.6 while third place was held by coleus ‘Altoona’ and Bokcelia’, caladium ‘Moonlight’ and basil ‘Sweet Dani’ with ratings of 4.5. Fifth place was held by caladium ‘Florida Fantasy’ and ‘White Water’ with ratings of 4.4, pennisetum ‘Purple Majesty captured sixth place with a rating of 4.3 and seventh place was shared by Iresine ‘Purple Lady’, marigold ‘Inca II Primrose and petunia ‘Tidal Wave Cherry’ with ratings of 4.2. Eighth place was mixed with basil ‘Magical Michael’, celosia ‘Glow Carmine’, marigold ‘Inca II Gold’, petunia ‘Wave Lavender’ and vinca ‘Victory Red’ all rating 4.1 while ninth place was shared by celosia ‘Fresh Look Red’, marigold ‘Inca II Yellow’ and ‘Perfection Mix’, petunia ‘Tidal Wave Purple’ and vinca ‘Cooler Coconut Improved’ and ‘Victory Lavender with ratings of 4.0. Tenth place was the largest with petunia ‘Explorer Lavender’, ‘Explorer Pink’, ‘Ramblin Burgundy Chrome’ and ‘Wave Rose’, portulaca ‘Margarita Scarlet’, and vinca ‘Cooler Orchid Deep’, ‘First Kiss Rose’, ‘Sunstorm Apricot’, ‘Sunstorm Orchid’ and ‘Victory Purple’ all rating 3.9.
Spring at the trial gardens in
Auburn and Cullman were difficult this year because the winter rains kept
coming and coming. Normally we plant the garden in early May but this year
was delayed until mid June. There is just no use in trying to cultivate
and plant when you sink up over your ankles in mud! Without question, the
real show stopper in Auburn was Alternanthera ‘Purple Knight’,
but give it plenty of room. It is a large plant at about 3 feet by 3 feet.
The petunias and coleus were also strong contenders with 42 percent of the
top 10 petunias and 29 percent coleus. We have had the Florida Sun Series
coleus perform well for us in the past but I was surprised by the petunias,
especially the Explorer and Wave series. I don’t know if their strong
performance this year was due to slightly milder weather or if real progress
has been made in developing petunias for the southeast, I hope the former.
Vincas and begonias also did well as usual but more so at Cullman than Auburn.
It is the first time we have had the ornamental peppers in our garden and
I encourage every landscaper or home gardener to give them a try. Just don’t
be tempted to eat them. I was impressed with the low, creeping growth habit
of vinca ‘Mediterranean Punch’. I think it has potential for
special applications such as front of the border, rock gardens and hanging
baskets.
The story at the Cullman trials was all about
the sun tolerant coleus occupying 29 percent of the top 10. The sun tolerant
caladiums and vincas were also strong contenders. Eight of the 14 caladium
entries were in the top 10 and 17 percent of the top 10 were vincas. Petunias
did not make as strong a showing at Cullman as they did at Auburn. However,
portulaca, marigold, celosia, basil, iresine, and pennisetum performed better
at Cullman than at Auburn. At Auburn, many of the entries peaked early and
declined rapidly. It appears from this study that in the southeast, summer
annuals need to be successively planted in order to have an attractive garden
throughout the long growing season. Homeowners need to be educated as to
this fact. Growers and retailers may be able to extend their market season
if enough consumers recognize this fact.