May 2008

Winter Winners By Jennifer Boldt, Jessica Boldt, Jim Barrett and Rosanna Freyre

It just wouldn't be winter in the South — or spring in the rest of the country — if pansies, one of the most popular garden plants, didn't show their faces in gardens and planters. Landscapers and home gardeners need bright spots of color early in the season from plants that will survive possible frosts and freezing temperatures. Many exciting plant choices are available that can be used as a complement or replacement to pansies and create stunning, long-lasting color displays.

This winter and spring we evaluated more than 200 cultivars at the University of Florida Trial Garden for frost and freeze tolerance, cool-season performance, potential season-extending heat tolerance and landscape potential. Entries were planted into the garden in mid-November from 80-millimeter Ellepots and evaluated every two weeks from late December until mid-April for garden performance. Temperatures in winter and early spring can vary from 50s to 80s during the day and 20s to 50s at night (see Table 1 for weather data), similar to conditions in Midwestern states in late spring.

The following cultivars are our top performers from this year's winter trial and should be considered for winter color in the South and early-season sales in other parts of the country.

Calibrachoa 'Superbells Dreamsicle'

Calibrachoa tend to have some difficulty when planted in the ground and are typically thought of as a container crop. However, 'Superbells Dreamsicle' from Proven Winners filled out nicely and was one of the first calibrachoa cultivars to begin flowering in early March. It has medium-green leaves and orange flowers with a darker orange throat and veins. It will grow about 10-12 inches tall and will complement harvest colors in the fall or bright colors in the spring. We had five cultivars of Superbells calibrachoa in the trial this year, and Saffron and Scarlet were very similar to Dreamsicle in flowering performance and growth habit.

Carnation 'Garden Spice Fuchsia'

This cultivar from Fides North America has a uniform growth habit and rose-colored flowers with a light fragrance. As with most other carnations, 'Garden Spice Fuchsia' flowers in flushes. It had the good trait of tending to flower over the old, dead flowers, hiding them in the can-opy. Some deadheading would help with the overall appearance, but it is not required. The Garden Spice series has a wide range of colors but varies in growth habit, amount and length of flowering, and whether deadheading is required.

Chrysocephalum 'Flambe Yellow'

Proven Winners has two chrysocephalum cultivars available, 'Flambe Orange' and 'Flambe Yellow'. 'Flambe Orange' has been previously recognized as one of the top performers in our summer trials thanks to its heat tolerance and continuous flowering, and now it is time to recognize its counterpart. 'Flambe Yellow' does not perform quite as well during our humid summers because of its denser plant habit, but it outshines 'Flambe Orange' in the winter trial. It is more cold tolerant and showed no damage, even when temperatures dipped into the mid-20s. Being drought tolerant, this cultivar would be a great addition to low-water-usage landscapes, and its silvery-green leaves add interest to a container or garden even when it is not in flower.

Delphinium 'Mistral Star'

This cultivar from American Takii is a dwarf delphinium that will grow to only about 2 feet tall. Compared with the classic delphinium, it has smaller leaves and flowers and fewer flowers per inflorescence, but don't be deceived by its wispy and delicate appearance: This delphinium performed very well in the garden. The flowers are iridescent blue with white centers and a small speck of violet on the edge of each petal. The combination of flower color and short stature allows this cultivar to have a wide range of uses in a garden setting or by itself in a container.

Diascia 'Wink Pink Improved'

Diascia is a crop that has been around for a while, but it's not a staple item in most gardens. Landscapers and gardeners may think it looks too delicate to be used for landscape beds, but it can certainly hold its own and provide excellent color. 'Wink Pink Improved' from Ball Horticultural Company (Ball FloraPlant) adds a cheery, light-pink color to the winter palette. It suffered light freeze damage when our temperatures dropped to the mid-20s, but it showed no damage with temperatures in the upper 20s and low 30s. As with most diascia, 'Wink Pink Improved' will tend to flower in flushes but rarely goes completely out of flower.

Erysimum 'Citrona Yellow'

'Citrona Yellow' from Ball Horticultural Company (PanAmerican Seed) is a repeat winner from our winter trial last year. Two colors are available in the Citrona series, orange and yellow, and both have similar growth habits. 'Citrona Yellow' is slightly more vigorous and earlier to flower than 'Citrona Orange' but has slightly less heat tolerance. Both are excellent winter annuals and have about the same degree of heat tolerance as pansies. The flowers are borne on inflorescences above the foliage and will sway in the breeze, creating some additional visual interest. It isn't necessary to deadhead the plants, but doing so will help its appearance towards the end of the season.

Erysimum 'Variegatum'

This erysimum is a Proven Selection from EuroAmerican Propagators, which provided excellent visual appeal during the entire season. It has bicolor leaves, light green in the center and cream-colored along the margins. During its first two months in the garden, plants filled in nicely and had great foliage interest. Then it started blooming, and light lavender inflorescences opened all over the plant. It will work as an accent plant in mixed containers or the landscape, regardless of whether it's in flower.

Petunia 'Potunia Pink'

'Potunia Pink' from DŸmmen USA is another repeat winner from the trial: It was named one of our best new varieties last spring. It has soft-pink flowers that fade to light pink as they age. This cultivar was one of the first petunias to begin flowering this spring, and it had good flower coverage by the last week of March. All of the cultivars in this series have a naturally compact plant habit, making them well-suited for large-scale production and tight spacing. They will not spread aggressively like a Wave or Wave-type petunia in the garden, but they'll work well in small spaces or as a border plant. Window boxes and hanging baskets are also excellent options for showcasing the petunias' nice mounding habit.

Snapdragon 'Solstice Burgundy'

'Solstice Burgundy', a seed-propagated snapdragon from Ball Horticultural Company (PanAmerican Seed), will grow to a medium-sized 18 inches tall and was one of the earliest snapdragons to flower this spring. It has a full, well-branched plant habit and produces a multitude of inflorescences with rich burgundy-colored flowers. The older flowers tend to develop a white area on the lower lip, leading to a slightly bicolored appearance when viewed up close. The only drawback to this display of color is that it tends to flower in flushes, so it will need to be paired with other annuals that can offset it in the garden when it is not in full bloom.

Viola 'Penny Deep Blue Improvement'

An excellent alternative to pansies is its small-flowered buddy, the viola. They may have smaller flowers than pansies, but the abundance of flowers provides an excellent display of color in landscapes. This cultivar from Goldsmith Seeds was one of our top-rated entries in the trial and the highest-ranked viola. It has intense, deep-blue flowers that vary slightly in coloration from flower to flower but provide a unified overall block of color that would pair very nicely with orange- and yellow-hued flowers. The plants have a uniform growth habit and will grow about 12 inches wide and 6 inches tall.

Viola 'Penny Denim Jump-Up'

This cultivar, also available from Goldsmith Seeds, is a cute bicolored viola with a dark-purple wing and a lavender-blue face with a speck of yellow in the center. It has medium-sized flowers for a viola and flowered all winter. The plant habit is uniform and slightly more compact than 'Penny Deep Blue Imp.' It was planted directly opposite to dark orange snapdragons in the garden, which created a striking color combination. Violas are versatile in the garden and can be used in mass plantings, window boxes or combination planters.

Viola 'Starry Night'

'Starry Night' is the third repeat award winner selected this year, chosen as a best of trials in our winter trial last year thanks to its heat tolerance. It is a vegetatively propagated viola available from Ball Horticultural Company and is more vigorous than seed-propagated violas. Its flowers are intermediate in size between pansies and violas, and are light yellow with purple edging. It flowered continuously from its planting in November and should continue to flower until late May.

Additional Information

Pictures and evaluation data for all of the cultivars in this year's trial will be posted to our website (http://trialgarden.ifas.ufl.edu) in early summer. Data from previous trials can be found on the website under the "Archives" link.