Report from the Southern Trials, Part II

October 3, 2003 - 07:16

The University of Florida puts some favorites to the test.

Last month, we covered the results of most of our focus
crops for the University of Florida spring/summer 2003 trials. However, there
were so many great new plants as single entries in the trials that I really
felt we needed to cover them in a separate issue where there would be enough
space to focus on both field performance and a little bit of culture
information.

In case you didn't get a chance to read it last
month... The trials are planted each year into ground beds amended with
mushroom compost at 1 yard per 100 sq.ft.; the pH of the beds ranges from
6.2-6.7; and a thick layer of aged pine bark is applied after the soil is
prepared. At planting, 72-cell liners are placed directly into the beds on
12-inch centers, and 4 grams of Osmocote 18-6-12 is incorporated around each
plant. Plants are then watered-in overhead by hand, and subsequent watering is
done through drip tubes similar to commercial vegetable production irrigation
systems. Plants are evaluated every other week for initial flowering and peak
flowering, evaluated with a five-point system and rated on performance,
diseases, pests, etc. We do not apply any fungicides or pesticides, except
glyphosate to control 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 of entries surrounding it. The trials run from approximately April 1 to
July 31.

Bananas

We only trialed four varieties this year, but I hope in the future
we can trial even more of the diversity from this incredible tropical impact
group. Again, these plants were planted from 72-cell liners, and most were over
10 feet tall five months later. I was impressed with the overall speed of
growth, as leaf size on many cultivars exceeded 7 feet. Flowering would occur
next year, and so it is not part of our trial.

One of the most interesting bananas we had this year was
planted in the landscape and not a part of the formal trials. This species,
Musa velutina (Boondox Tropical's), has been flowering for three months with
brilliant pink bracts and fruit. This particular plant was planted from a
7-gal. pot, so it already had a year of growth behind it; we'll be looking to
formally trial this species next year.

Bananas are an underutilized annual for Northern markets.
Because of its growth speed, Northern growers could start with liners and avoid
a lot of the shipping issues that occur when trying to move larger plants.

Varieties to consider: 'Rojo' (Agristarts) has dark purple
markings that really stand out in plantings; the other cultivars were green
foliage types. 'Pace' (Agristarts) received lower ratings because it was unable
to support its own leaves (7-10 feet in length), and foliage bent at the
petiole throughout the season.

Native Plants

We are adding a larger component of native plants into our
trials for a couple of reasons, and this year gave us some very good material.
Part of the reason for native plants is the obvious connection to lower
irrigation, reduced chemical usage and an increasing governmental interest in
these plants. However, I wanted natives in our trials to see how they compared
to cultivars of similar species and hybrids where there has been a lot of
selection in the release process. There were a few real standouts in terms of
performance and potential. There were also a few that lack either ornamental
qualities or were late summer to fall flowering and therefore did not fit well
into the summer timeframe.

Coreopsis leavenworthii (Micanopy Wildflowers) began
flowering quickly after planting and continued to hold good color through most
of the season. The lanky growth habit will pose some problems for commercial
production, but landscape habit and flowering were excellent. The native blanket
flower, Gaillardia pulchella (University of Florida/IFAS-IRREC Collected) did
so well, we are doing a focus trial of gaillardia next year to check out more
of the commercial hybrids.

We were lucky enough to get a couple of good native lantana
species this year, and I have inserted the ratings for some commercial
varieties into  Figure 2, bottom,
to show how the native species compare. I was very impressed with Lantana
depressa (University of Florida-IFAS-IRREC), which has a flower color similar
to 'Gold Mound', but with a more open habit and a lighter green leaf. These
species could certainly be adopted immediately into landscape use in the Deep
South. Lantana involucrata (University of Florida-IFAS-IRREC) has pale pink
flowers and a much lower color impact in the landscape, but the Á growth
habit was mounding and fairly dense, so it certainly has potential as well.
Lantana 'Morning Glow Orange Yellow' and Pink Yellow (Bodger Botanicals) had
excellent flowering and color, but the growth habit of Pink Yellow was a bit
leggy so ratings were lower.

There is still a big difference in commercial cultivars
versus native species. Bodger's two releases have much higher color and impact,
but for growers looking to incorporate native species, there is definitely some
potential here.

Miscellaneous crops

'Gold Flake' mecardonia (Proven Selections) turned out to be
much tougher than it looked. (Imagine a dichondra with brilliant yellow
flowers.) I was really impressed with the performance and flowering season in
full sun. Throughout the summer, the plant remained in bloom, and foliage held
up to summer rains. The natural foliage color is a pale green, but the flowers
are striking. This would be an excellent component crop in mixed containers for
a trailing growth habit. In shade, the plant lost its vigor, so in production,
keep light levels high!

'Festival Star' (Proven Winners) baby's breath is a
heat-tolerant gypsophila, which as far as I know is a first. This is usually a
winter annual in the South, but the dwarf cultivar has bloomed all summer and
is self-heading, so old flowers drop off and new ones take their place style="mso-spacerun: yes">  —  very nice.

'Ebony' Eranthemum (Proven Selections) was also a pleasant
surprise. I was thinking all summer, "Why not grow a coleus instead?"
as the somewhat glossy black foliage was nice, but the plant was less vigorous
than coleus and seemed to fit the same niche. That is, until it began flowering
in small spikes of white flowers with pink centers — very cool. Plants
grew to 3 feet tall and were very uniform. At least for us in the South, the
late-summer flowering is really nice! Having seen this plant in the trials one
season, I can now see where it would shine. In mixed containers, the high vigor
of coleus can overrun other plants. Ebony could provide contrasting foliage
color without getting out of control. In production, keep this plant warm, as
it did not grow much in the trials until night temperatures were above 65º
F.

Colocasia 'Rhubarb' (Proven Selections) predictably grew
very well. Like most elephant ears, it loved heat and moisture. The good part
is that it doesn't sucker, or at least hasn't yet. In the Deep South, colocasia
that produce suckers are on the hit list of every invasive plant movement, so
this clumping characteristic, in addition to beautiful rhubarb-colored stalks,
makes this a great addition to the landscape or large mixed containers. Leaves
are a dusky gray green, but the petioles are, as the name implies, bright red
with subtle streaks of deeper colors.

Florida city series coleus (Lake Brantley Plant Corp.) had
some great cultivars. As these are selected in Florida, it is no surprise they
have heat tolerance, but the bright, clear red tones and the vigorous growth,
which should translate into good growth for Northern production, are what I
really liked. 'Hurricane Louise' (Hatchett Creek Farms) was last year's best
coleus for upright habit, good branching and no flowering. This year, it held
its own again, with a strong growth habit, tolerance of low water and only two
flower spikes out of 40 plants. Erika really liked 'Stained Glassworks Copper'
(The Flower Fields) for color and habit; I preferred 'Gay's Delight' (Proven
Selections) because the growth habit was very compact and well branched.

In scaevola, flower size and late season performance really
separated cultivars, but 'Brilliant' (Horticultural Marketing Associates) and
'Whirlwind White' (Proven Winners) were both excellent and long lasting. I
think the unique, somewhat upright habit of Whirlwind really sets it apart from
the rest.

To get the full story of the trials, check the trials Web
site (http://hort.ifas.ufl.edu/floriculture/springtrials2003) so you can
compare what I say with data and digital pictures taken every two weeks
Á throughout the season. Also, due to the number of cultivars presented
here, please use the Web site to locate sources for this material, as all
entries on the Web site indicate the suppliers.

Author's Note: We would like to thank all contributing
companies and sponsors for their support of the 2003 spring/summer trials. The
list is long and this type of trialing can only be effective with the
cooperative efforts of our industry. Our main Floriculture Field Day will be
held May 19-20, 2004. The field day is held in Gainesville, Fla. and includes
two days of educational programs as well as trial garden tours.

About The Author

Rick Schoellhorn is extension specialist and Erika Berghauer is trials manager at the University of Florida, Gainesville, Fla. They can be reached by phone at (352) 392-9806 and Email at erikamb@ufl.edu.

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