Selecting this Spring’s Sensations

July 14, 2008 - 10:59

How do you know which plants will be easy to produce while providing excellent landscape and garden performance? Observing new cultivars at university trial sites is a great way to gauge their performance across a range of climates and growing conditions.

At the University of Florida, our early plant date allows us to be one of the first trial sites to independently evaluate new introductions. This year, we trialed more than 850 cultivars, including more than 280 new introductions for 2009.

Our typical schedule calls for receiving plugs and liners in late February, planting them into 80-mm Ellepots, growing them in a greenhouse and transplanting into the trial beds in late March and early April. Plants remain in-ground through August, and our evaluations are divided into spring and summer seasons, with top performers selected at the end of each season.

Our spring season comprises plant evaluations during April and May. We award three honors: “Best New Varieties,” “Outstanding New Varieties” and “Best of Trials.” This article will focus on the “Best New Varieties.” Varieties are selected for consistent, excellent garden performance throughout the entire evaluation period. This year, our average temperatures during April and May were 80/54° F and 88/63° F, respectively, with approximately 11?2 inches of total rain.

Calibrachoa ‘MiniFamous Tangerine’

Typically, it is difficult to grow calibrachoa well in our trial beds because of our native soil’s high pH. This year, all calibrachoa was grown in 14-inch pots (two pots per cultivar with four plants per pot) in a 30 percent shade house and then displayed on the trial beds during our Field Days. ‘MiniFamous Tangerine’ from Selecta First Class was one of our top-performing calibrachoa. The light orange–colored flowers with a dark orange eye and veining stand out when planted alone; it also works well as an accent plant in combination plantings. Over time, while other calibrachoa pots started to open in the centers and develop an irregular growth habit, this cultivar maintained a mounded growth habit, cascading halfway down the pot. It flowered consistently across the canopy and has shown no signs of chlorosis.

Coleus ‘Indian Summer’

Coleus is a classic landscape plant for spring and summer because of its wide variety of leaf shapes and colors. ‘Indian Summer’, a vegetatively propagated cultivar from Ball Horticultural Co., has ruffled red leaves with flecks of green and dark red scattered across the leaf surface. Plants filled the plot (12-inch spacing) within six weeks of planting and have maintained a full plant canopy. By early June, plants were approximately 2 feet tall with no signs of lodging. While other coleus started flowering in early May, ‘Indian Summer’ had not shown any signs of flowering by early June. It will perform well either as a mass landscape planting or by itself in a patio container.

Geranium ‘Caliente Fire ’09’

‘Caliente Fire ’09’ is a new cultivar added to this heat-loving series from Syngenta Flowers. All other cultivars have medium-green leaves, but this selection has very dark-green leaves paired with blackish-red flower stalks and velvety dark-red flowers. It is an interspecific hybrid, and although it does not have the full-flowered inflorescence seen in zonals, it makes up for that with inflorescence number. The old flower spikes turn brown, fall off and do not require deadheading — definitely a favorable attribute for geraniums! It has a mounding growth habit and completely filled its plot by the end of May, which is a feat for geraniums in Florida. It appears to have good heat tolerance and is performing as well as the other colors in this series. ‘Caliente Fire ’09’ has potential to be used as a landscape geranium and will require little maintenance to keep it looking good all season.

Heliotrope ‘Scentropia Dark Blue’

‘Scentropia Dark Blue’, also available from Syngenta Flowers, has fragrant, dark purple-blue flowers and a nice mounded growth habit. By the end of May, it was about 2 feet tall in the garden and very full. It was one of the favorites of the attendees during both our Master Gardener and public open houses. This cultivar is early to flower and began flowering while still in the greenhouse. Very little growth regulation will be needed to keep its growth in check, so it appears to be a good selection for a 4-inch or 1-gallon container program.

Lobelia ‘Techno Heat Dark Blue’

Recent strides to increase the heat tolerance of lobelia are amazing. Three years ago, only two lobelia cultivars in our trial still looked good the first week of June, but this year, almost a dozen cultivars from three suppliers were still alive and flowering profusely. Lobelia ‘Techno Heat Dark Blue’ from Syngenta Flowers is one of the standouts. Intense dark-blue flowers completely covered the plant in a cloud of color for almost six weeks. Its compact growth habit lends itself nicely to high-density greenhouse production. They are early to flower, grow best when not overwatered, and will need very little to no PGRs if shipped when ready for sale.

Ornamental Pepper ‘Calico’

‘Calico’ is an ornamental pepper available as a seed item from Ball Horticultural Co. It has variegated green, white and purple leaves; small purple flowers; and dark black-purple fruits. This foliage coloration is not a common sight in our trial garden, and it commanded a lot of attention from visitors. Plants grew to about 18 inches tall two months after planting and have a uniform habit. Plants were easy to grow in the greenhouse and can provide a welcome splash of color in mixed containers as a foliage accent or as a swath of color in a landscape bed. It has been reported that ‘Calico’ fruits are hot, but no taste tests were done to confirm this.

Petunia ‘Potunia Lobster’

‘Potunia Lobster’ from Dümmen USA is a new addition to the existing Potunia series and has the same compact, mounding habit that makes this series so production-friendly. Flowers are salmon-colored with darker veining and really have the color of a lobster shell after it has been boiled! While many of the other petunias had almost completely stopped flowering or begun to lodge by early June, ‘Potunia Lobster’ maintained its growth habit, flower coverage and performance. It is also easy to grow in the greenhouse because its branches do not intertwine with adjacent pots and plants require little to no PGR applications. Lobster works well in the landscape as a border or mass planting, as well as in mixed containers or hanging baskets.

Petunia ‘Supertunia Vista Silverberry’

‘Supertunia Vista Silverberry’ from Proven Winners has light silver-pink flowers with darker veining and a mounding-spreading growth habit. It is very similar to ‘Supertunia Vista Bubblegum’ in growth habit and landscape performance. Many petunias look great in our garden in April and May but decline rapidly as the temperatures increase and the summer rains start. During the last week of May, many petunias began to show signs of stress, but ‘Supertunia Vista Silverberry’ still performed extremely well. It grows quickly in the greenhouse and has a short production time. Due to its mounding habit, plants do not get severely intertwined even when grown in tight spacing. However, when growing in smaller containers, the use of PGRs to keep growth in check would definitely be beneficial. Its vigor and growth habit are well suited for 1-gallon or hanging basket programs.

Ptilotus ‘Joey’

‘Joey’ was one of the most talked-about new introductions at Pack Trials this past April thanks to its novel appearance. Ptilotus exaltatus is native to Australia, and Benary’s ‘Joey’ is the first commercial introduction for this genus. It has airy, fluffy pink-purple flower spikes at practically every node. As growers, landscapers, industry professionals, Master Gardeners and the general public walked through the garden, they all seemed to be drawn to ‘Joey’. We are not sure how it will hold up during our hot, humid summer months, but it performed exceptionally well during our spring. ‘Joey’ flowers very early, which will help it sell more easily at retail, but initially can look slightly spindly until more secondary branches develop. Two words of caution: Do not overwater plants early in production, and make sure the hypocotyl is strong and not too thin or elongated; otherwise, the plant may have stability issues, similar to pansy or petunia plugs.

Verbena ‘Empress Strawberry Charme’

‘Empress Strawberry Charme’ from Dümmen USA has large, bright-pink flowers with a big white eye. It flowers uniformly across the plant canopy, not just on the edges, and the bicolored flowers are easy to spot from across the garden. It is a fast grower and will fill a landscape area quickly. On the flip side, its growth will need to be controlled during production to prevent rooting into neighboring pots. ‘Empress Strawberry Charme’ will work great as a mass planting in the landscape and in mixed containers. Unlike some of the other verbena in the trial, it has shown no signs of decreased flowering as temperatures regularly exceeded 90° F.

As always, our trial is open to the public until late August. Our website, trialgarden.ifas.ufl.edu, shows results of our evaluations for each entry. Thank you to all the participating companies for allowing us to independently trial their plant material, and we look forward to selecting the summer award winners!

About The Author

Jennifer Boldt is trial coordinator, Jessica Boldt is a graduate research assistant, Jim Barrett is professor of floriculture and Rosanna Freyre is a research scientist at the University of Florida in Gainesville, Fla. Jennifer can be reached at jkboldt@ufl.edu.

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