August 2003

Report from the Southern Trials Part I By Rick Schoellhorn and Erica Berghauer, University of Florida

Well it’s finally feeling like a normal Florida summer, witha half inch of rain every afternoon and temperature and humidity at around 90.Since we had a relatively dry summer, a lot of plants that traditionally giveup the ghost in June have persisted into August. That’s good because it tellsus a lot about heat tolerance. Oddly enough, powdery mildew was not a problemthis year, as it had been in the past. With over 340 entries and 19 basiccategories of plants in the 2003 spring/summer trials at the University ofFlorida, there is a lot to cover.

The trials are planted each year into ground beds amended withmushroom compost at 1 yard per 100 sq.ft.; the pH of the beds ranges from6.2-6.7; and a think layer of aged pine bark is applied after the soil isprepared. At planting, 72-cell liners are placed directly into the beds on12-inch centers and 4 grams of Osmocote 18-6-12 is incorporated around eachplant. Plants are then watered-in overhead by hand, and subsequent watering isdone through drip tubes similar to commercial vegetable production irrigationsystems. Plants are evaluated every other week for initial flowering and peakflowering, evaluated on a five-point system and rated on performance, diseases,pests, etc. We do not apply any fungicides or pesticides, except glyphosate tocontrol weeds. After the first weeks of planting, we also do not deadhead,pinch or trim, unless an entry is so vigorous it threatens the ratings ofentries surrounding it. The trials ran from approximately April 1 to July 31.

To get the full story with data, check the trials Web site,(http://hort.ifas.ufl.edu/floriculture/springtrials2003), so you can comparewhat is said here with pictures taken every two weeks. So here are the plantsin the groups we classified on the Web site to facilitate crossover. Also, dueto the number of cultivars presented here, please use the Web site to locatesources for this material.

Angelonia

This year, the Angelonia were the field portion of theFlorastar Elite trials, as well as being one of our focus crops, so there werefewer entries, and the trial does not cover the scope of the industry by anymeans. It was great to have a chance to do some field trialing of these plants,as they have so much potential, and the genetics are there for some incredibleadvancements in the near future. I hope we will be doing these again once someof the new releases make it on to the market.

We trialed from the Angelface (Proven Winners), Angelmist(BallFlora Plant) and Carita (The Flower Fields) releases, all of which hadgood performance in the garden. In the entire season, there was only one strongflush of flowering, though it lasted roughly six weeks and garnered a verystrong performance. This is partly because we started with liners rather thanfinished materials. All entries performed very well; however, the amount oftime they spent growing and not flowering reduced their overall ratings. Thehighest marks went to ‘Angelface Blue’ and ‘Angelmist Purple Stripe’ forearlier flowering and longer bloom seasons.

Annuals

There were 81 “annuals” this year, and we lumpedall the plants that were not focus crops into this category. There were somestar performers here that deserve a lot of credit for exceptional performance.These are plants that had superior performance this year.

Intensia Phlox. TopPerformance in the garden. Proven Winners really struck gold on these plants.Normally Phlox drummondii hybrids are short-lived, cool season annuals, but theIntensia series were far superior to anything we have seen before. The plugswere in bloom when planted and began to show some signs of foliar loss in August,otherwise they stayed at a perfect five rating throughout the entire summer.This is a crop to be looking at for spring and summer sales.

Doublette Begonias.These double hybrids of Begonia sempervirens-cultorum were incredible in fullsun throughout the season; through today, they remain in full bloom with nodisease or insect problems at any time. In our consumer and studentevaluations, these plants also came out as top picks. It was almost boring howconsistently great they were!

Dreamland Zinnia.Again, this not a plant we expect to hold up through summer in Florida. Add tothis, that we did not deadhead spent flowers or clean the plants in any way.Throughout the season, these plants held up and are only now — in late Julyand August — starting to succumb to leaf spot, Anthracnose and Botrytis. Areally strong performer for zinnias, definitely heat tolerant and diseaseresistant.

Diva Vinca. This isthe second year for trialing this series from Danziger “Dan” FlowerFarm, and again, they have performed excellently. There is some variability inthe series, with Salmon Pink having the lowest vigor in both seasons, but allare good performers. These plugs went through a record late frost and stillperformed all season long. There were some losses of lower foliage towards theend of July, with the advent of summer rains, but still a good strong showingfrom this series.

Calibrachoa

This crop was part of the Flora Star Elite trials and afield focus crop last year. The results of the greenhouse portion of the trialswere in the July issue of GPN, and honestly calibrachoa has a better life as awinter or early spring crop for the Deep South rather than the late season. Anyentries planted late, due to shipment, had bad overall ratings because withoutthe benefit of early cool temperatures, the plants could never get up to sizeand give a good showing in the landscape.

One might argue that calibrachoa is not a landscape crop,but why shouldn’t it be? It has the potential to be a very strong, early springcrop and can be winter planted in the Deep South for early spring sales. Wetrialed 22 cultivars, and there were huge differences in performance based ongenetics. The really bad ratings all went to late entries. Note that the periodbetween weeks 20-24 was the peak season for this group.

Double Impatiens

This crop was part of the Flora Star Elite trials and afield focus crop. Again, this is not a crop traditionally thought of aslandscape material, much less full sun landscape material, but we wanted theseplants in the field to look at sun, heat and humidity tolerance. These plantscontracted Rhizoctonia fairly early in the season, so we actually looked atRhizoctonia effects as well. Top ratings for double impatiens went to ‘Fiesta SalsaRed’ (BallFlora Plant), ‘Double Up White’ (Bodger Botanicals) and ‘FiestaBurgundy Rose’ (Ball Flora Plant), for surviving the trials and having a betterpresentation of flowers, as well as a vigorous growth under some pretty toughconditions. Overall, ratings were fairly low in this group due to some insectpressure, as well the presence of Rhizoctonia in that bed.

Double Vegetative Trailing Petunia

This was a field trial focus crop. Double vegetativepetunias are an expanding market with many different genetics available. Duringearly season performance, all entries performed beautifully and had highratings; the major impact on ratings came in late season. We actually hadpetunias still blooming in August, which for Florida is nearly unheard of, butthis year, disease pressure was lower and entries lasted longer. Personally, Iwas really impressed with the Double Wave series by PanAmerican Seed, whichcontinued to flower into July and August. Remember that a rating over 3.0 forthe season is very strong!

Verbena

This is another group of plants that dodged a bullet thisyear in our trials, as we had no powdery mildew at all. For verbena in the DeepSouth, that pathogen is one of the main reasons for late-season performancemelt down. This year, many of the entries were still attractive in August; theyweren’t at peak by any means but still of landscape value, which is veryimpressive. ‘Donalena Red’ received the highest ratings although both Donalenaand Veralena varieties got a lot of interest during the industry field days inlate May. Many of the Tapestry series were very strong as well and stillreceiving high marks as we head into August. All in all, it was a very goodyear for verbenas.

The authors would like to thank all contributing companiesand sponsors for their support of the 2003 spring/summer trials. The 2003winter trials are planted October 15, and spring 2004 trials planted April 1.Our major Floriculture Field Day will be held May 19-20, 2004.