May 2005

Keeping Cuts Current By John Dole

Cut flower growers are a demanding group of people. Upon seeing a beautiful flower, most folks would comment first on how pretty it is. Not cut flower growers — they will ask "Can I make any money with that?" and "Sure it's pretty, but will it last?" These questions are often followed with "How tall will it grow?", "Does it have a good stem?" and "Are there any other colors?" Like I said — not an easy group of people to please.

Each year the Association of Specialty Cut Flower Growers (ASCFG) and North Carolina State University attempt to do just that — please cut flower growers. We evaluated more than 100 cultivars in three trial programs this year and are discussing the best ones in this article. The figures provide information on stem length, productivity and trialer's ratings. In addition, for the first time, we asked trialers to report the postharvest life they were able to obtain, trying to answer that age-old question "Will it last?" Please keep in mind that most folks have not had the time to do any testing, so the vase life listed is without special treatments. NC State also conducted extensive postharvest testing on the most promising new cut flowers, and details will be presented in a future GPN article.

Each of the three trial programs rely on volunteers to evaluate the plants. For the seed trial we had 49 trialers from all over the United States, including Hawaii and Canada, of which 35 returned results. The trialers are primarily commercial growers of all size operations, but also include a handful of universities and suppliers. For the perennial and woody trials we had eight and 10 trialers, respectively, of which six and five trialers, respectively, were able to return results. Trialers provided evaluations at the end of the year to NC State. Full details — including comments made by trialers about the cultivars — can be found in The Cut Flower Quarterly.

Seed Trials

Highlights of this year's trials included the release of three series that are likely to become important for cut flower growers: ProCut sunflowers, Sweet dianthus and Camelot digitalis.

Sunflowers. The sunflower ProCut series from SeedSense includes orange, lemon and bicolor cultivars. This well-matched series did very well in the trials. All were uniform, reliable and fast. 'ProCut Orange' flowered up to two weeks earlier than 'Sunrich Orange'. These single-stem cultivars produce medium-sized flower heads with a long postharvest life, averaging 7-9 days. One respondent wrote that it was their "favorite new sunflower," and another said it was the "Best sunflower I've grown in a few years!" Sunflower 'Double Quick' from SeedSense also scored very high in the trials. This large double-flowered sunflower had a short crop time but not as fast as the ProCut series.

Digitalis. One of the trends in ornamental breeding has been to shorten crop time by eliminating cold requirements for flowering. Delphiniums and Amazon dianthus are two notable examples. The next genus to get the star treatment is digitalis. With the release of Camelot from Goldsmith Seeds, digitalis has become a vigorous, rapidly flowering plant that does not require a cold treatment for flowering. At NC State we had uniform flowering in May from a late January sowing. Other digitalis cultivars, such as Foxy, will also flower the first year from seed, but Camelot is fast and uniform. Camelot is available in white, cream, lavender and rose. Plants were very productive, averaging 4-5 ç stems per plant, with some trialers harvesting up to 20 stems per plant. Stems were a bit short, averaging 19-22 inches, but long enough for most growers to use. Goldsmith notes that if the plants survive the summer heat, they will flower the next year with much longer stems, up to 3 feet tall. Digitalis is often grown as a summer or fall planted biennial for maximum stem quality, and Camelot should be tried this way also. Postharvest is acceptable for local sales, averaging 6-9 days, but too short for some trialers, especially those who ship. The main problem was that the lower florets dropped. Certainly this series would benefit from additional postharvest testing.

Dianthus. PanAmerican Seed has been busy remaking sweet william-type dianthus, and its hybrid Amazon dianthus is quite a milestone. These robust plants flowered the first year from seed, exhibited great heat tolerance and produced long stems. The Sweet series is more of a traditional sweet William, with shorter stems and a little less heat tolerance than Amazon. This is not surprising considering that the Sweet series is not a hybrid. However, Sweet dianthus still has much to offer the grower. It is uniform, rapid flowering — generally about 2-3 weeks before Amazon ç — and productive. Stem length averaged around 15 inches with some trialers getting up to 28 inches. Postharvest life averaged 8-10 days. Sweet dianthus is available in white, coral, red and purple — the latter two colors were sometimes difficult to tell apart.

Snapdragons. This was the year of the snapdragon, with 22 cultivars submitted from three companies. Snapdragons have traditionally not done well in the trial program because they generally should be planted earlier than we can get the seed from the suppliers and out to the growers. However, that did not appear to be a problem this year, as a number of the cultivars did very well. The Opus series from Goldsmith received high marks from trialers. 'Opus Plum Blossum' and 'Opus Yellow' did well enough to be nominated for the 2005 ASCFG Cut Flower of the Year. Opus snapdragons produced 6-8 stems per plant, and stem lengths averaged 22-28 inches long. Certainly snapdragons are most impressive when grown in the greenhouse or tunnel, but many of these cultivars produced wonderful cuts outdoors.

Campanulas. For a number of years Sakata Seed America has been working on campanulas. Most growers are familiar with their ç Campanula medium Champion series, which has become a staple of greenhouse or tunnel production. This year Sakata released Campanula rapunculus 'Heavenly Blue'. This cultivar produced sprays of small, pale purple, upright facing, bell-shaped flowers. Plants were productive, averaging seven stems per plant, and 23 inches long, with some folks getting up to 31-inch stems. Stems are thin but strong and easy to use in bouquets and arrangements. Vase life ranged from 7-14 days with the average being 11 days.

Larkspur. One of our old standby cut flowers, larkspur, received some attention this year. American Takii took the larkspur in a different direction with its 'Chorus Violet', the first spray type larkspur. It produced numerous stems topped with small, purple flowers. Stems averaged 27 inches long with a vase life of more than 10 days. Our plants showed a variety of plant habits, but this could be remedied by pinching plants when young. Kieft Seeds submitted larkspur 'Sydney Lilac' as part of their series bred for greenhouse or tunnel production. Several trialers used 'Sydney Lilac' in tunnels with great results. Stem length averaged 25 inches, a bit short for larkspur; however, some folks had stems 39 inches tall, showing the potential for this cultivar. The 'Super Single Imperial Orchid' larkspur from Fred C. Gloeckner & Company also did well. Trialers loved the beautiful color, and one person noted that it flowered well into summer. Stem length averaged 23 inches.

Zinnia. Ernst Benary of America has expanded the colors available in its productive Oklahoma zinnia series. Carmine, Yellow and Ivory were tested in the trials and received high marks for productivity, more than 12 stems per plant, good stem length and a high degree of doubleness. The color of 'Oklahoma ç Carmine', in particular, received a lot of attention.

Perennial Trials

This year's perennial trial highlighted a few unconventional plants. Neither persicaria 'Brush Strokes' nor 'Silver Dragon' (Terra Nova Nurseries) were particularly notable as cut flowers but were great as cut foliage. 'Brush Strokes' has large, light green leaves with darker bronze markings, and 'Silver Dragon' has small, burgundy leaves that age to silvery green with burgundy veins. One trialer commented on 'Brush Strokes' that the "nice wide leaf provides different texture to arrangements," and another said "I am excited to use it in bouquets next year." 'Brush Strokes' does not produce flowers until very late in the season — only 25 percent of trialers had flowering. 'Silver Dragon' is much more floriferous, but to be honest, the flowers are small; the foliage is easier to use without the flowers. Stem length for both cultivars averaged 22-24 inches. Growers harvested eight stems per plant for 'Brush Strokes' and 40 per plant for 'Silver Dragon'. Interestingly, while consumers appeared to like persicaria and it worked well in mixed bouquets, the florists and wholesalers were apparently less interested. One trialer noted that 'Brush Strokes' had a vase life of 12 days, and several trialers reported that the vase life for 'Silver Dragon' was 11-31 days.

Andropogon. Another interesting plant was the grass Andropogon 'Silver Sunrise', derived from our native grasses. This bluestem has a ç bluish green color during the summer that darkens to burgundy in the fall. While one trialer thought it looked like a weed; another referred to the 39-inch-long stems as "a designer's choice at the retail florist." Trialers reported an average vase life of 10 days.

Lobelias. Lobelias have always been among my favorite flowers for their intense reds, blues and purples. Lobelia 'Ruby Slippers' is no different, with long spikes, averaging 31 inches, of rich red flowers that everyone seemed to appreciate. Postharvest is always a concern with lobelias, but the vase life of 'Ruby Slippers' ranged from 8-10 days.

Echinacea. The purple coneflower is undergoing a revolution with many new and interesting forms and hybrids now on the market. This year's selection, Echinacea purpurea 'Ruby Star', is one of the standard coneflowers, but it is a great one. It produced 22-inch or longer stems topped with spectacular flowers. The large flowers have bright purple, horizontal petals with a rich, orange red cone. Trialers averaged a little more than five stems per plant.

Campanula. Campanulas are always interesting, and the trial included two species and adenophora 'Amethyst', a relative of campanula. 'Amethyst' had long spikes of nodding, purple flowers. Stems averaged 28 inches long, and trialers harvested approximatey 14 stems per plant. The plant was easy to grow and flowered over a long period. Campanula 'Kent Belle' also had purple flowers, but they were larger. Stems were approximatey 23 inches long, and growers harvested eight stems per plant. Trialers reported an average vase life of nine days for 'Amethyst' and 11 days for 'Kent Belle'.

Rudbeckia. While many rudbeckias are best treated as an annual, Rudbeckia triloba can be handled as a short-lived perennial. This very productive plant produces sprays of dark-centered, yellow flowers on 36-inch stems. One person noted that the "flowers make into arrangements quickly." Trialers harvested a little more than 10 stems per plant. The plant is easy to grow.

Woody Trial

As woody cuts have become increasingly important to the cut flower industry, the ASCFG realized it needed to address this area and established the Woody Cut Trials in 2003. The U.S. National Arboretum, two suppliers (Bailey Nursery and Spring Meadow) and 10 trialers have kicked off this program. Plants were received fall 2003 and spring 2004. Considering the interest in woody cuts, we are quite pleased to be able to fill this gap in our trial programs. Only one problem: We don't have much to report at this time. Yes, most woody plants take some time to reach harvestable age, and of the 17 cultivars in the trial only a handful grew fast enough to have an idea of how they will do. We have included the comments and ratings for those species.

It is apparent already, however, that callicarpa 'Early Amethyst' and hydrangea 'Limelight' are fast growing and productive plants. Here at NC State we harvested stems from our plants in the first year, as did a number of the trialers. Average stem length was 19 inches for 'Early Amethyst' and 18 inches for 'Limelight'. We expect longer stems next year as the plants begin to mature. Another ç comment about 'Limelight' — the flower clusters are large and impressive. Although it is early, 'Limelight' already seems like a winner to us, as shown by the high ratings. Physocarpus 'Diabolo' was also impressive this summer. The bronzy foliage makes a great cut, with stems averaging 32 inches long.

ASCFG Cut Flowers of the Year

Fresh Cut Flower of the Year. Top interior designers say that every room needs a splash of red. There is no easier way to introduce a little dazzling red to the home than with a few stems of ilex 'Winter Red'. 'Winter Red's' brilliant color coupled with the striking architecture of its bare branches will provide just the right amount of drama for any room.

Accolades are nothing new when it comes to 'Winter Red'. This multi-stemmed North American native is a winner of multiple awards. Available anytime from October through January with a profusion of large 3?8-inch fruits covering the stems. Plants are cold hardy in Zones 3-9 and should be spaced 3-5 feet or wider in the field and propagated by cuttings. Male and female flowers are on separate plants. Females are desired for berries, but males are needed nearby for pollination. It generally requires five years to reach harvestable size.

Harvest when fruit are well colored. Cut stems may last up to 12 weeks in water; however, as with many species, the vase life in foam will be much shorter. Stems should be stored dry. Branches may be stored at 32¡ F for 1-3 weeks in moisture-retentive boxes. Cut stems with dried berries persist in the home for months in a dry container.

Dried Cut Flower of the Year. Funky is the best way to describe the bright purplish-bronze seed pods of nigella 'Cramers' Plum'. Dramatic arrangements can be made with just 'Cramers' Plum' in a glass vase or by combining it with a soft-textured dried grass to accentuate the strong lines of the nigella. These pods can be used either fresh or dried. Dried pods last for years if kept out of direct sun and dusted occasionally. The unusual flowers are occasionally harvested for fresh use.

This seed-propagated annual has narrow, highly dissected leaves and grows 18-24 inches tall. The tallest plants are usually obtained with direct seeding, which can occur either in the spring (cold climates) or fall (warm climates). Space plants 3×3 to 9×9 inches apart. Tight spacing encourages larger terminal flowers and fewer side branches.

Harvest pods when fully expanded and well colored for fresh use and when firm to the touch for dried use. Nigella tends to reseed itself, so handle it accordingly.