Talk of the Summer Trials

This year was a good year for a lot of crops and not such a good year for others. In common with other year’s results we saw a few common markers that separate performance in the Sunbelt from performance in more Northern regions of the state. Our spring was noticeably shorter this year than last, and by the first rains of June the spring materials began to drop in ratings within days. We struggled with pH in some of the crops early in the season, and as a result their performance was really limited. Still as of August 1 there were some outstanding performers in the garden that held up all through the May to August season despite the weather. The first eight weeks of the trial showed high ratings on most plants, while temperatures were still cool at night and humidity was low; the second eight weeks of the trial were the real stress test, when average night temperatures rarely got below 72° F, and average daytime temperatures were as high as 95° F with 70- to 90-percent humidity.

Our rating system is simple and similar to that used at many other trial gardens around the United States. We base our ratings on a 6-point system (0 = lowest to 5 = highest marks):

  • 0 = Plant is dead.
  • 1 = Plant is growing poorly, with little vigorous growth and little or no flowering.
  • 2 = Plant is growing and flowering but not performing well enough to merit use.
  • 3 = Plant is growing and flowering enough to be considered of acceptable performance. If it isn’t flowering it can’t have a rating higher than 3 unless it is a foliage color crop.
  • 4 = Good growth and flowering with enough impact to be considered a strong candidate.
  • 5 = Plant is at peak performance with exceptional flowering and vigorous growth.
  • — = Plant was planted late.

Remember that ratings are taken every two weeks, so average ratings will be lower as plants flower cyclically and cannot always be a perfect 5. When averaged over the entire season, a rating of 2.5 or above tells you the plant has an extended season of interest; an average rating much below a 2.5 means that the plant did not have a long enough season of interest to be of use under our conditions. Another thing to remember is that a plant with a great show of color for four weeks but poor growth/color at other times will usually be rated lower than a plant with only acceptable performance over the entire season.


Agastache. Agastache is an old-fashioned crop that is making a comeback due to some new-to-the-market hybrids with improved performance. One of the releases from PanAmerican Seed a few years ago was the Honey Bee series in white and blue, great bee attractors with good early season performance. This year we did not have the Honey Bee series but focused on agastache from the species A. cana and its hybrids. The Agastache cana group looks much more like salvia, with long tubular flowers, highly scented foliage and a longer season of performance.

The releases from Bodger Botanicals in the Acapulco series are a great performing group that can bloom early, have larger individual flowers and are much more compact than ‘Heather Queen’ (the old standard for this crop). The flowers and buds are different colors, giving a variety of tones on the plant all at once.

‘Acapulco Salmon Pink’seemed to have more flowers and more consistent color over the plant, giving it the highest rating in the comparison. Heather Queen is a much rangier plant with lavender tones and narrow flowers; it is vigorous and about 18 inches taller and 36 inches wider in the landscape. ‘Apache Sunset’ (A. rupestris) was similar in form and habit to the Acapulco series but much later to flower, with bright orange flowers and somewhat smaller, thinner blooms. The most threadlike flowers belonged to ‘Pink Pop’, which was less vigorous than Acapulco but massed with very threadlike pink flowers. The other two entries ‘Golden Jubilee’ (A. foeniculum) and ‘Korean Mint’ (A. rugosa) are more in line with the Honey Bee series having spikes of fuzzy flowers packed only on the upper edges of the canopy, a more upright in habit and lower ratings in late-season performance. All the agastache are great plants, but selecting the types that flower earliest is the best route to success. Both Pink Pop and Apache Sunset did not flower until late in the season and were the only two plants that did not receive an acceptable performance rating.

Basil.Herbs continue to grow in popularity, both for containers and landscapes. We ended up getting most of our plant material from an independent retailer for 2004 but hope to have more breeder participation in future trials. We were looking for attractive growth and habit, as well as delayed flowering. Early season performance was strong for most of the varieties tested, but late-season growth was a lot more variable. All ratings suffered as heat and humidity took their toll, but ‘Swiss Sunset’, ‘Osmin’ and ‘Aussie Sweet’ held up really nicely. Aussie Sweet and ‘Columnar’ appear to be the same plant, and both have a late-flowering characteristic that kept plants clean and excellent for cutting, very compact. I had seen Hishtil’s ‘Magic Mountain’ at Pack Trials and was really impressed with flower color and size, but under our heat and humidity the flowers were reduced in size and faded in color. The plant in our garden has great foliage, and flowers are pale pink but still very vigorous and trouble free. I was really interested in seeing ‘Star Balsam’ (I don’t believe it is basil) due to some great flowering potential at Pack Trials. However, heat and humidity never gave it a chance to get going.

Gaillardia.I think the gaillardia trial was one of the most interesting of the focus groups this season. This is a crop that doesn’t get a lot of press, and the old-fashioned varieties have always been a problem for producers to get into flower at a salable size. There are some great new options and a lot of overlap in cultivars. The top performer was ‘Torch Red Ember’ from Ball FloraPlant. It received top marks for uniform flowering, compact growth, a great deep burnt orange color and a long season of interest. ‘Arizona Sun’ from Ernst Benary of America came in a close second; the plants were not quite as uniform as I had hoped, but they were early flowering and held on for color throughout the season. Plant Haven’s ‘Fanfare’ also had very high ratings, unique flowers and blooms cycled in and out throughout the season. In regards to flower color, in the clear yellow flowers we could tell no difference between ‘Gold Goblin’, ‘Indian Yellow’ or ‘Yellow Flame’; in the samples we received they were all identical . ‘Lollipop Gold’ was a great, uniform double yellow from Sahin Seed. Only ‘Red Plume’, also from Sahin, was a true burgundy color, while ‘Burgundy’ was clearly orange and yellow. Sahin’s Lorenziana mix had a lot of great half tones with fully double flowers and was also quite nice. Every other cultivar in the trials — 16 of them — were orange with a yellow edge, the intensity of the orange varied only slightly between entries. Most consumers who came to the trials had a hard time differentiating between them.

Pentas. Pentas is a crop that has both a big seed and vegetative market. We trialed 28 cultivars and found some large differences in size, foliage quality and flower power. Figure 4, below, rates the pentas entries by size: large, medium and compact. Every cultivar had acceptable ratings and some much higher, but this is part of the country where pentas really excel and thrive. Lower ratings are usually the result of foliar problems (‘New Look’ and some of the Monarchs) or a lack of solid, flower power. In each category the Monarch varieties have the highest ratings, which was a bit of a surprise, as it is one of the least known series of pentas on the market. The Monarch series was developed by Earl J. Small Inc. and has some of the nicest unique colors I have seen in this crop so far. With the planned closing of Earl J. Small, the Monarch and Monarch Petite series are moving to Yoder Brothers and will be available Á through them in the future. There are many non-patented varieties of pentas available through Hatchett Creek and Robrick Nurseries and its brokers. Call me old fashioned, but I still really prefer the large, old-fashioned vegetative pentas for their vigor in the landscape, although they can be a bit of a challenge to control in a pot. With vigorous pentas you’re best bet in controlling elongation is repeated applications of paclobutrazol — rates vary with the part of the country you grow in, but in the Deep South use sprays of up to 45 ppm and drenches of somewhere between 6 and 10 ppm as plants reach salable size. Northern growers would use a lot less chemical, and seed cultivars require less PGRs than the vegetative types.

Phlox.For three seasons two varieties of phlox have impressed me — both Intensia (Proven Winners) and the Astoria (Jackson & Perkins) are phenomenal performers, with both winter and summer potential. Intensia are a bit more vigorous, and their colors are not as distinct. Still, what a great group of plants; you can see that while they performed well through the early season, they really began to peak in mid summer. If you try nothing else this year, try some of these plants in gallons and baskets; they will be a great addition to your crop line. Their heat and humidity tolerance is unparalleled in the genus.

Torenia.Another category where Proven Winners and Jackson & Perkins have some fantastic genetics! Vegetative torenia are excellent in full sun to part shade in the Southern United States. ‘Catalina Blue’ is a great new addition, and along with ‘Summer Wave Blue’ holds more color than most other entries. The ‘Elite Lavender Blue’ from Jackson & Perkins is a great new color and vigorous grower. All these plants are strong performers, and while the order shifts a bit each year we trial them, they are all excellent plants.

Miscellaneous Crops

This is my favorite group of crops, and there is a lot of wonderful material in here, but for the sake of simplicity I’ll only be able to cover a few of these plants. For complete trials information and pictures throughout the season, check out our Web site at:

‘Missy Ann’ coleus — North Carolina Farms. What a great new color form of coleus! This cultivar is truly a unique combination of tones and has a really classy look and great heat tolerance. We received lots of good material from this small nursery, and I look forward to hearing more from them.

‘Red Velvet’ mandevilla — Lake Area Nurseries. John Gray from Lake Area Nurseries has some great new forms of this popular vine, and we’ll be trialing more next year. Red Velvet has a slightly deeper color and somewhat lower vigor than ‘Alice DuPont’ but overall a nice introduction.

Artist ageratum — Proven Winners. This long-lasting series has a good habit, and ‘Artist Purple’ is a great color!

‘Mellangolly Blue Scoparia’ — Proven Winners. ‘Mellangolly Blue Scoparia’ is another Proven Winners introduction with a lot of potential. Feathery green foliage filled with small sky blue flowers — a really unique and a great high-end item for retailers.

Cooler vinca — PanAmerican Seed. ‘Cooler Pink’ and White vinca went all through the summer rains with no foliar problems and had great color.

AngelMist angelonia and Aurora coleus— Ball FloraPlant. AngelMist, as well as the new Aurora coleus, continue to perform beautifully. ‘Aurora Black Cherry’ was the most stable of the cultivars and also the latest flowering.

Tweedia and Browallia. Two oddball showstoppers that got attention from industry and consumers were Tweedia caerulea (also sold as Oxypetalum caeruleum), ‘Blue Milkweed’ and Browallia americana from Peace Tree Farms. These are all novelty plants with both long-lasting interest and unique colors.

Tropicanna canna — Anthony Tesslaar. ‘Tropicanna’ and ‘Tropicanna Gold’ cannas were also a great addition this year, with unique coloring and uniform growth. These are some beautiful cannas; I was amazed at how tough they turned out to be in a relatively dry location of the gardens.


University of Florida rates crops to let you know which are the best for you.

About The Author:

Rick Schoellhorn is extension specialist at the University of Florida, Gainesville, Fla. Marc Frank is a graduate student at the University of Florida and an extension botanist for the Florida Museum of Natural History. Rick can be reached by phone at (352) 392-1831 x364 or E-mail at [email protected]

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