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q '- UNIVERSITY OF
Institute of Food and Agricultural Sciences
Gulf Coast Research and Education Center
5007 60th Street East, Bradenton, FL 34203
GCREC-Bradenton Research Report BRA-1997-09
TWO YEAR EVALUATION OF Vj Ig1998
CULTIVARS IN THE FLORIDA LANDSCAPE
University of -orida
T. K. Howe and W. E. Waters
GCREC Research Report BRA1997-9
TWO YEAR EVALUATION OF VIOLA CULTIVARS IN THE FLORIDA LANDSCAPE
T. K. Howe and W. E. Waters'
Gulf Coast Research & Education Center
University of Florida, IFAS
5007 60th Street East
Bradenton, FL 34203
The wholesale value of Florida-grown bedding plants was $88.4 million in 1995 from growers with
product sales exceeding $100,000 (Fla. Agr. Stat. Serv., 1996), compared to the total national value
of $1.32 billion (USDA, 1996). These returns made Florida the fifth largest producer of bedding
plants behind California ($173 million), Michigan ($131 million), Texas ($106 million), and Ohio ($92
million). These five states account for 45% of the total bedding plant market value from the 36 states
surveyed. California declined 4% from the previous year, while Florida increased 2%.
Two comprehensive field trials of viola cultivars were conducted at the Gulf Coast Research &
Education Center in Bradenton, FL during the winters of 1994-95 and 1995-96. An attempt was
made to select an assortment of floral colors to survey the major series currently available to the
industry. The cultivars were evaluated for earliness of flowering, flower diameter, flower color, plant
dimensions, flower coverage, flower display, and plant uniformity.
MATERIALS AND METHODS
Transplant Production- Seeds of viola cultivars were sown into germination flats (20- channel flat
with dome cover) filled with a peat:vermiculite medium (1:1, v:v, amended with dolomite,
superphosphate and hydrated lime) on 3 October 1994 and 2 October 1995. Seedlings were
transferred to 1.5 x 1.5 x 2.5 in. (128-cell flats) filled with the above peat:vermiculite medium.
Transplants received liquid fertilizer as needed after transfer. No plant growth regulators were used
in this study.
Field Preparation- Beds ofEauGallie fine sand were formed to a width of 2.7 ft and a height of 8 in.
on 5 ft centers under full sun. Slow release fertilizer at a rate of 29.6 lb/1000 ft2 OsmocoteTM 18-2.6-
11.2 (N-P-K) was applied over the full bed surface and incorporated to a depth of 3 to 4 inches.
Beds were fumigated with 67% methyl bromide: 33% chloropicrin (350 lb/A) and covered with white
on black polyethylene film mulch. The area was irrigated by subsurface seepage via two ditches
spaced 40.5 ft apart. Eight cultivars in 1994-95 and 15 cultivars in 1995-96 were set into beds on 9-
inch centers in three rows across the bed on 28 November 1994 and 1995. Four replications of nine
plants per cultivar were arranged in a randomized complete block design.
'Research Program Coordinator, Variety Trials and Center Director, respectively.
Data Collection- Cultivars were evaluated for time to flower from sowing, flower size and color,
plant dimensions, and habit. Subjective ratings were assigned 6-7 February 1995 and 19-20 February
1996 based on a zero to 10 scale (where 0 was no plant survival and 10 was excellent) to assess plant
uniformity, floriferousness, floral display, and overall appearance. Trials were terminated on 1 April
1995 and 1 May 1996.
RESULTS AND DISCUSSION
Weather. In the 1994-95 season, temperatures were higher than normal in December, and March,
while below normal in January and February (Table 1). Rainfall was higher than normal in December
and January and lower than normal in February and March. In the 1995-96 season, daily maximum
temperatures were at or below normal for the entire season, and daily minimum temperatures were
below normal the entire season. Rainfall was below normal in December, February and April, while
above normal in January and March.
1994-95 Season. The number of days from sowing to first flower among 8 cultivars from 3 series
ranged from 68 days for 'Jewel Blue' to 80 days for 'Jewel White' (Table 2). Six cultivars flowered
in 71 days or less, while only two took 76 days or more. Flower sizes, measured across the middle
petals, ranged from 1.1 in. for 'Jewel Blue' to 1.3 in. for 'Jewel White', 'Jewel Blue with Face' and
'Velour Blue'. No series predominated in large or small flower size.
Plant heights at 121 days after sowing ranged from 4.8 in. for 'Miniature Violet' to 9.1 in. for 'Jewel
Blue'. 'Jewel Blue' was significantly taller than any other cultivar. 'Miniature Violet' was smaller than
any 'Jewel' cultivar, but similar to both 'Velour' cultivars. Plant widths ranged from 8.4 in. for
'Miniature Violet' to 14.4 in. for 'Jewel Purple with Face'. 'Jewel Blue', 'Jewel Blue with Face' and
'Jewel Purple with Face' were significantly larger in width than the other five cultivars. In a trial
conducted in 1996-1997, the 'Jewel' series had the largest viola plants at season's end (Howe and
Very few differences were observed in the subjective ratings among cultivars with respect to plant
uniformity and floriferousness, and none in overall appearance.
1995-96 Season. The number of days from sowing to first flower among 15 cultivars from 4 series
ranged from 71 days for 'Sorbet Blackberry Cream' to 81 days for 'Princess Lavender-Yellow' (Table
3). Seven cultivars flowered in 74 days or less, while eight cultivars flowered in 75 days or more.
Unlike the previous winter, a single series stood out as predominately later to flower, the 'Princess'
series. When specific floral colors were compared across series lines, one significant difference was
found: 'Sorbet Lemon Chiffon' flowered 4 days later than 'Sorbet Blackberry Cream'.
Flower diameters ranged from 1.2 in. for 'Princess Cream' and 'Princess Purple & Gold' to 1.5 in. for
'Sorbet Lavender Ice' and 'Velour Purple'. Again, no single series consistently produced larger or
smaller flowers than any other.
Plant heights measured 117 days after sowing ranged from 4.4 in. for 'Princess Yellow' to 6.5 in. for
'Jewel Maroon & Yellow'. 'Jewel Maroon & Yellow' was significantly taller than all other cultivars.
Of the 3 series trialed, no single series was prominent with respect to the tallest or shortest plants.
Plant widths within series were significantly different in some cases. 'Princess Blue' was taller than
any other 'Princess' cultivar, while 'Sorbet Lavender Ice' and 'Sorbet Purple Duet' were shorter than
'Sorbet Yellow Frost'.
Plant widths ranged from 7.4 in. for 'Princess Cream' to 12.1 in. for 'Sorbet Yellow Frost'. 'Sorbet
Yellow Frost' and 'Sorbet Blackberry Cream' were larger in diameter than any other cultivars,
including those within the 'Sorbet' series. Among the 'Princess' series 'Princess Purple & Gold' had
a greater plant diameter than 'Princess Cream'.
Subjective ratings showed few differences among the cultivars in plant uniformity, floriferousness,
or overall appearance. No differences were evident among the cultivars in the flower display.
Weather tolerance was best for 'Jewel Maroon & Yellow', 'Princess Lavender-Yellow', 'Princess
Purple & Gold', 'Sorbet Blackberry Cream', and 'Velour Blue'.
Plant Habit. Growth habit differences were obvious among the cultivars, particularly early in the
season. Differences were dramatic enough in some cases to make a series unbalanced. For instance,
'Jewel Blue', 'Jewel Blue with Face', 'Jewel Purple with Face' spread and formed continuous mats of
vegetation on the beds, but 'Jewel Yellow', 'Jewel White' and 'Jewel Maroon & Yellow' were more
upright, compact and individual. In a trial conducted in 1996-1997, the 'Jewel' series was
exceptionally nice, creating a thick blanket on the beds by season's end (Howe and Waters, 1997).
The 'Velour' series was well-matched for habit with all cultivars producing upright plants which
barely touched each other late in the season. The 'Princess' series was fairly well-matched where
three of the five colors had definite free-standing and individual plants, while 'Princess Lavender
Yellow' and 'Princess Purple & Gold' tended to form cohesive mats. The 'Sorbet' series had plants
of four of the six cultivars which formed thick blankets across the beds, while two, 'Sorbet Lavender
Ice' and 'Sorbet Lemon Chiffon' remained more individual and just touched. Conversely, in a 1996-
1997 trial, at the end of the season most plants of the 'Sorbet' violas conserved the appearance of
individual, petite, upright plants, while 'Sorbet Blackberry Cream' and 'Sorbet Yellow Frost' plants
were more spreading and coalesced into mats (Howe and Waters, 1997).
Selection of viola cultivars for landscape use from among those examined can be based on several
criteria. Ignoring quantitative analysis, choice might be made on flower color and novelty value
alone. However, information about earliness to flower, flower size, floral display, mature plant size,
floriferousness, plant uniformity and habit allow a more definitive selection. Some cultivars were not
consistent within series groups with respect to measured variables thus selection for landscape use
may be determined best by individual cultivar rather than by entire series.
Florida Agricultural Statistics Service. 1996. Foliage, floriculture and cut greens. Fla. Agr. Stat.
Serv., Orlando, FL.
Howe, T. K. and W. E. Waters. 1997. Summary of flowering bedding plant trials fall and winter
1996-1997. GCREC Bradenton Res. Rept. BRA1997-xx. (In press).
Stanley, C. D. 1996. Weather report for 1995, Gulf Coast Research and Education Center,
Bradenton, FL. Bradenton GCREC Res. Rept. BRA1996-06.
United States Department of Agriculture. 1996. Floriculture crops. 1995 summary. USDA Natl.
Agr. Stat. Serv. Sp Cr 6-1(96).
Table 1. Temperature and rainfall at the Gulf Coast Research & Education Center, Bradenton, FL during the winters of 1994-95z and
1995-96z with comparison to the 42-year means (Stanley, 1996).
Daily Mean Temperature (F)
Maximum Minimum Rainfall (in.)
Month/Year 1994-95 42-yr mean 1994-95 42-yr mean 1994-95 42-yr mean
December 94 75 74 56 52 3.39 2.22
January 95 71 72 49 50 3.09 2.79
February 95 73 74 51 52 2.22 3.01
March 95 85 78 57 55 2.57 3.45
1995-96 42-yr mean 1995-96 42-yr mean 1995-96 42-yr mean
December 95 72 74 50 52 1.16 2.22
January 96 72 72 49 50 3.95 2.79
February 96 70 74 49 52 1.00 3.01
March 96 75 78 52 55 5.50 3.45
April 96 81 82 58 60 1.58 1.83
zFields planted on 28 November 1994 and 1995, the three days in November are not shown.
Table 2. Growth and performance of viola cultivars in field beds during winter 1994-95.
Flower Plant Plant Ratiihgsx
Days to Diametery Heighty Widthy
Cultivar/Series Source Flower' (inches) (inches) (inches) Uniformity Flowering" Overall'
Jewel Series American Takii
Blue 68 bU 1.1 c 9.1 a 14.1 a 8.8 ab 8.5 ab 8.4 a
Blue with Face 69 b 1.3 ab 6.5 bc 13.9 a 8.9 ab 8.6 ab 8.8 a
Purple with Face 71 b 1.2 bc 7.2 b 14.4 a 8.9 ab 8.4 ab 8.6 a
Yellow 71 b 1.2 bc 6.7 bc 9.5 bc 8.1 b 9.4 a 8.5 a
White 80 a 1.3 a 7.2 b 10.9 b 9.3 ab 9.0 ab 9.3 a
Miniature Violet Grimes 76 a 1.2 a-c 4.8 d 8.4 c 9.6 a 8.5 ab 8.6 a
Velour Series Floranova
Blue 70 b 1.3 ab 4.9 d 9.2 bc 9.3 ab 8.3 b 8.3 a
Purple 71 b 1.2 a-c 5.3 cd 9.6 bc 9.5 a 8.9 ab 9.1 a
TFrom sowing 3 October 1994.
YMeasured 31 January 1995.
"Rating scale: 10 = excellent, 9 =superior, 8 = very good, 7 = good, 6 = fair, 5 = borderline acceptability; 1 = very poor, 0 = all dead. Rated 23
February 1996. Rating converted for statistical analysis. Mean separation by Tukey's procedure at 5% level. Numerical data is
in unconverted, original form.
"Flower density and distribution.
'Inclusive rating for appearance and vigor.
"Mean separation by Tukey's procedure at 5% level.
Table 3. Growth and performance of viola cultivars in field beds during winter 1995-96.
Flower Plant Plant Ratings"
Days to Diameter' Height' Width' Floralf Weather'
Cultivar/Series Source Flower' (inches) (inches) (inches) Uniformity Flowering" Display Overall' Tolerance
Jewel Maroon & Yellow
Purple & Gold
"From sowing 2 October 1995.
YMeasured 26 January 1996.
"Rating scale: 10 = excellent, 9 =superior, 8 = very good, 7 = good, 6 = fair, 5 = borderline acceptability, 1 = very poor, 0 = all dead. Rated 23
February 1996. Ratings converted for statistical analysis. Mean separation by Tukey's procedure at 5% level. Numerical data is in
unconverted, original form.
"Flower density and distribution.
Flower position to viewer.
"Inclusive rating for appearance and vigor.
iG = good, F = fair, P = poor.
'Mean separation by Tukey's procedure at 5% level.
The Gulf Coast Research and Education Center
The Gulf Coast Research and Education Center is
a unit of the Institute of Food and Agricultural Sci-
ences, University of Florida. The Research Center
originated in the fall of 1925 as the Tomato
Disease Laboratory with the primary objective of
developing control procedures for an epidemic out-
break of nailhead spot of tomato. Research was ex-
panded in subsequent years to include study of sev-
eral other tomato diseases.
In 1937, new research facilities were established
in the town of Manatee, and the Center scope was
enlarged to include horticultural, entomological, and
soil science studies of several vegetable crops. The
ornamental program was a natural addition to the
Center's responsibilities because of the emerging in-
dustry in the area in the early 1940's.
The Center's current location was established in
1965 where a comprehensive research and extension
program'on vegetable crops and ornamental plants is
conducted. Three state extension specialists posi-
tions, 16 state research scientists, and two grant
supported scientists from various disciplines of
training participate in all phases of vegetable and
ornamental horticultural programs. This interdisci-
plinary team approach, combining several research
disciplines and a wide range of industry and faculty
contacts, often is more productive than could be ac-
complished with limited investments in independent
The Center's primary mission is to develop new
and expand existing knowledge and technology, and
to disseminate new scientific knowledge in Florida, so
that agriculture remains efficient and economically
The secondary mission of the Center is to assist
the Cooperative Extension Service, IFAS campus
departments, in which Center faculty hold appropri-
ate liaison appointments, and other research centers
in extension, educational training, and cooperative
research programs for the benefit of Florida's pro-
ducers, students, and citizens.
Program areas of emphasis include: (1) genetics,
breeding, and variety development and evaluation;
(2) biological, chemical, and mechanical pest manage-
ment in entomology, plant pathology, nematology,
bacteriology, virology, and weed science; (3) produc-
tion efficiency, culture, management, and counteract-
ing environmental stress; (4) water management and
natural resource protection; (5) post-harvest physiol-
ogy, harvesting, handling and food quality of horti-
cultural crops; (6) technical support and assistance to
the Florida Cooperative Extension Service; and (7)
advancement offundamental knowledge of disciplines
represented by faculty and (8) directing graduate
student training and teaching special undergraduate
U The Institute of Food and Agricultural Sciences,
University of Florida.
0 A statewide organization dedicated to teaching,
research and extension.
O Faculty located in Gainesville and at 13 research
and education centers, 67 county extension
offices and four demonstration units throughout
" Partnership in food and agriculture, and natural
and renewable resource research and education,
funded by state, federal and local government,
and by gifts and grants from individuals, founda-
tions, government and industry.
Q An organization whose mission is:
Educating students in the food, agricultural,
and related sciences and natural resources.
Strengthening Florida's diverse food and
agricultural industry and its environment
Enhancing for all Floridians, the application
of research and knowledge to improve the
quality of life statewide through IFAS exten-