View images and tables on page 33-38 here.

The favorite perennial this year was rudbeckia ‘Henry Eilers’ (Terra Nova). With its quirky quilled petals and long, strong, easy-to-cut stems, this flower has many admirers. Plants are productive, yielding an average of 20 stems each that were a little over 2½ feet long. Some trialers cut up to 33 stems per plant, and others up to 45-inch stems. ‘Henry Eilers’ starts producing quickly; marketable stems were harvested from first-year plants, averaging twelve 23-inch stems per plant. Growers also noted the lack of problems with this vigorous cultivar.

Equally productive was Lecanthemum ‘Paladin’ (Terra Nova). It produced an average of 24.7 stems that were 13½ inches long. Some folks harvested 20-inch stems. Plants generated a large flush of flowers early in the summer and smaller numbers during the rest of the season.  The white daisies have yellow centers. The outer white petals are abundant, but sometimes not fully formed.

At Ko Klaver’s recommendation, we evaluated a few other perennials at NCSU which were not included in the national trial: achillea ‘Pink Grapefruit’ and ‘Wonderful Wampee’; echinacea ‘Meringue’, ‘Milkshake’, ‘Pink Double Delight’, ‘Sundown’ and ‘Sunrise’; eupatorium ‘Phantom’; and phlox ‘Blushing Shortwood’. Of these, the latter two really stood out.  ‘Phantom’ was a prolific flowerer of large clusters of small rosy pink blooms that work great as filler flowers. We have tested other eupatoriums in the past and this one is notable for being shorter and easier to manage than the species and some of the enormous cultivars available. In the second year we harvested 16 stems per plant that averaged 39 inches long. Even in the first year, we were able to harvest 5 stems that averaged 25 inches long. The easy-to-grow plants are cold and heat tolerant and flowered midsummer.

The large clusters  of fragrant phlox flowers are well known to many consumers. Here in the South, phloxes sometimes struggle a bit. One that has done well for us is ‘Blushing Shortwood’ with white flowers liberally tinged with pink. It produced two 13½-inch stems per plant the first year and nine 20-inch stems per plant the second. As with all phlox the petals tend to shatter unless treated with an anti-ethylene product.

The 2010 Seed Trial included several perennials that flowered from seed the first year.  One of our seed trialers, Tom Parker of Parkerhouse Nursery, overwintered the scabiosa and asclepias and reported back on the second year results. He found that all plants overwintered and scabiosa ‘Fama Deep Blue’ and ‘Fama White’ produced 10 to 15 stems and ‘Perfecta White’ 3 to 5 stems. ‘Fama White’ produced the shortest stems, around 20 inches, while ‘Perfecta White’ produced 19-25 inch and ‘Fama Deep Blue’ 21-24 inch stems. Asclepias ‘Oro’ produced 5 to 7 stems that were 14 to 16 inches long.

In the Woody Trial we are in the second year of testing several of the beautiful shrub roses from Kordes. Although we started with 10 trialers, we received results only from Tom Parker, Parkerhouse Nursery in New Jersey. A big thank you to him for reporting back. All of the plants in the trial (both NCSU and Tom Parker) survived the winter, except for ‘Corrie Freelander’ (only 1 out of 4) and ‘Honey Freelander’ (3 out of 4) for Tom. Our planting developed rose rosette virus, resulting in the loss of a number of plants (see table). There is no control for this disease once plants are infected, so the only response is to thoroughly remove them. For each cultivar, we listed the number of plants that were infected by the end of the growing season, but we suspect all are sensitive to the virus as most sources report little resistance to the disease by any roses. Rose rosette virus is spread by mites, which need to be controlled to prevent spread of the disease. A good web resource is from the Virginia Cooperative Extension (pubs.ext.vt.edu/450/450-620/450-620.html).

Black spot is a common disease of roses and there is variation among cultivars. We listed the black spot susceptibility of the cultivars in the trial (see table).

Tom reports that his planting of Kordes roses was hit hard by voles during the winter. Two inches of compost was applied to the raised beds and the compost was covered by an inch of decomposed wood chips. Bait and traps were employed to eliminate the voles. Plants recovered in the 2011 growing season, and he is anticipating good flower production in 2012.

Enough of the bad news—let’s focus on the flowers. Last year at NCSU we rated each of the cultivars according to fragrance, black spot, defoliation and thorns. ‘Perfumed Passion’ had the strongest fragrance, closely followed by ‘Mon Petit Chou’ and ‘Sweet Antique’. ‘Party Dress’ and ‘Antique Caramel’ had some scent, while the rest had limited fragrance. The worst for black spot was ‘Toscana’ and ‘Antique Caramel’. The cultivars with the least black spot were ‘Mon Petit Chou’, ‘Corrie Freelander’, ‘Party Dress’, and ‘Perfumed Passion’. Of these, all but ‘Corrie Freelander’ held most of their foliage by the end of the summer. However, ‘Samba’, ‘Toscana’ and some of the ‘Corrie Freelander’ plants had lost much of their foliage. Thorniness varied quite a bit from the very thorny ‘Samba’ and moderately thorny ‘Honey Freelander’ to the almost thornless ‘Corrie Freelander’. ‘Perfumed Passion’ and ‘Antique Caramel’ also had relatively few thorns.

Interpreting the trial results: The numbers reported are averages of all the respondents and many factors will affect the success of any plant species. Our participants are growing and harvesting the trial plants in a wide variety of ways. For example, with annual asters some people harvest the entire plant as one bunch while others harvest each individual flowering branch, giving very different stem lengths and yield data. After looking at the average, check the range of responses listed below each number to see how the cultivar performed at its best and its worst. If the range of responses in the ratings is narrow and high, i.e., 3-5 or 4-5, the plant was a winner for most of the respondents and is likely to do well for you. The “Repeat Again Rating” is particularly important because it indicates if the trialer would take the time, money, and space to actually grow the cultivar again. Review the trial results carefully. If a species sounds interesting but did not appear to do well, try it anyway. The cultivar may work well for you.  

Acknowledgments: All cut flower growers should thank the perennial and woody plant producers for providing the plant materials and the growers for producing the plants, collecting data and submitting trial reports. The growers paid shipping expenses and agreed to provide data for at least two years. Plants were donated by perennial producers and shipped as plugs or dormant roots directly to the trialers. I would also like to thank Ingram McCall for taking care of the North Carolina State University portion of the trials, and Brigitte Crawford, Diane Mays, Michelle McElhannon and Iftikhar Ahmad for assisting with the NCSU trials. In preparing the report we have edited the participants’ comments for space and clarity; my apologies if we’ve altered the tone or content of anyone’s comments. Thanks to everyone for making this service of the ASCFG possible.

Summary of Comments

The number in parenthesis refers to the number of respondents who made the comment. If no number is present, only one person made the comment. Comments by each individual are separated with a semicolon (;). Note: many respondents did not make specific comments on each cultivar and in some cases, comments have been shortened because of limited space.

2010 Perennial Cut Flower Trial Cultivar List – Year 2

Echinacea ‘Firebird’ (Terra Nova)
Good Qualities: Great color! (2); Strong stems, fragrance.
Problems: Few stems per plant.
Similar Cultivars: Echinacea ‘Firebird’, ‘Tangerine Dream’.
Postharvest Recommendations: Held in cooler at 33F.

Echinacea ‘Flame Thrower’ (Terra Nova)
Good Qualities: Very large, vibrant, dark redish-pink/purple flowers with stems slightly longer than other trial cultivars; Color and fragrance, strong stems, continued blooming all summer until frost, survived the summer!
Problems: Too many short stems.
Insects or Diseases: Gophers love all of our echinaceas; Leaves show what might be aster yellows virus, leaves were attacked by a huge swarm of caterpillars in late July.
Similar Cultivars: Echinacea ‘Firebird’, ‘Tangerine Dream’.
Postharvest Recommendations: Held in cooler at 33F.
Additional Comments: Compared to the standard/medicinal Echinacea purpurea grown from seed, this cultivar was less productive and had shorter stems; Gophers love all of our echinaceas.

Echinacea ‘Fragrant Angel’ (Terra Nova)
Good Qualities: Our customers really liked the unique combination of slender white petals and orange and yellow cones, these worked well mixed with other late-season flowers; I love the fragrance and the green and white color! Strong stems, continued blooming all summer until frost, survived the summer!
Problems: Too many short stems, white petals bruise and show brown/black spots that destroy their marketability.
Insects or Diseases: Gophers love all of our echinaceas; Leaves show what might be aster yellows virus, several plants died out over the summer, maybe because of the virus.
Postharvest Recommendations: Held in cooler at 33F.
Additional Comments:  Gophers love all of our echinaceas, compared to the standard/medicinal Echinacea purpurea grown from seed, this cultivar was less productive and had shorter stems; Stems were longer on all echinacea cultivars in this second year, compared to the 1st year. Our customers really liked Fragrant Angel’s unique combination of slender white petals and orange and yellow cones; these worked well mixed with other late-season flowers.

Echinacea ‘Green Eyes’ (Terra Nova)
Good Qualities: Love the bright pink color with the green center; Color and fragrance, I love the fragrance! Strong stems, continued blooming all summer until frost, survived the summer!; The light color of the centers of ‘Green Eyes’ was nice, but not too distinctive.
Problems: We lost several of these over the winter; Too many short stems.
Insects or Diseases: Leaves show what might be aster yellows virus, leaves were attacked by a huge swarm of caterpillars in late July after they finished eating ‘Flame Thrower’ leaves; Gophers love all of our echinaceas.
Postharvest Recommendations: Held in cooler at 33F.
Additional Comments: Gophers love all of our echinaceas, compared to the standard/medicinal Echinacea purpurea grown from seed, this cultivar was less productive and had shorter stems; Stems were longer on all echinacea cultivars in this second year, compared to the first year; Similar to ‘Fragrant Angel’, but with a different petal color.

Echinacea ‘Maui Sunshine’ (Terra Nova)
Good Qualities: Nice bright yellow; Strong stems; Another relatively unique echinacea color, though our plants tended more towards orange than the yellow in the Terra Nova catalog.
Problems: Not a strong plant, I think it may have died out before the summer was over.
Insects or Diseases: Gophers love all of our echinaceas.
Postharvest Recommendations: Held in cooler at 33F.
Additional Comments: Compared to the standard/medicinal Echinacea purpurea grown from seed, this cultivar was less productive and had shorter stems.

Echinacea ‘Pink Poodle’ (Terra Nova)
Good Qualities: The semi-double form and slender “petals” (ray flowers) were attractive and unique; Color, strong stems.
Problems: Inconsistent stem length and flower size; Plants seemed to have health problems, I doubt that many will be left in year 3, many short stems.
Insects or Diseases: Gophers love all of our echinaceas.
Postharvest Recommendations: Held in cooler at 33F.
Additional Comments: Compared to the standard/medicinal Echinacea purpurea grown from seed, this cultivar was less productive and had shorter stems. 2011 was the worst growing year I have ever experienced, beginning with record snowfall and record cold (February), followed by record rainfall (May), and record heat and drought (July and August). ‘Henry Eilers’ did well regardless.

Echinacea ‘Tangerine Dream’ (Terra Nova)
Good Qualities: Great, bright orange color (2); Strong stems.
Problems: Most died during the winter, and the rest died shortly after they came out in the spring; Short, inconsistent stem length and not enough stems per plant; Didn’t survive.
Insects or Diseases: Gophers love all of our echinaceas.
Postharvest Recommendations: Held in cooler at 33F.
Additional Comments: Compared to the standard/medicinal Echinacea purpurea grown from seed, this cultivar was less productive and had shorter stems.

Eucomis ‘Oakhurst’ (Terra Nova)
Problems: In two years in the ground, we have not yet seen a single flowering stem, original plants came in small and weak and we planted only a dozen of the original 20, lost about half of these in the first winter and going into the second winter we are down to only 3 plants, they look good but never showed any signs of flowering.
Additional Comments: Lacking flowers, we did harvest a few leaves to add to arrangements, we really liked the bronzy burgundy of the foliage and this color worked well with other elements of autumn.

Leucanthemum ‘Paladin’ (Terra Nova)
Good Qualities: Color, vase life; Very distinctive flowers for a Shasta-type daisy, they bloomed over a very long season, from late June onward and are still blooming now in early December, quite remarkable.
Problems: Short stems, many blossoms imperfect; Stem length can be a bit variable and never too many flowers at any one time, probably just need a larger stand to have a critical mass for each week’s harvest.
Postharvest Recommendations: Held in cooler at 33F.

Rudbeckia ‘Henry Eilers’ (Terra Nova)
Good Qualities: Nice, long stems, pretty flower sprays; Very long stems useful for larger design work, but so prolific that cutting stems short for “regular” work hardly seemed a sacrifice, our customers really liked the delicate architecture and open lines of ‘Henry Eilers’; Attractive alone or in mixed bouquets, long vase life, easy to grow with no disease or insect pest problems so far, do not need support net, plants were larger and more flower stems in second year.
Problems: None to speak of; Heavy bloom period was concentrated from mid-July through early August, with smaller clusters of flowers lasting until frost—not a bad problem, just doesn’t give an abundance over a long summer season.
Insects or Diseases: None (2).
Postharvest Recommendations: Definitely benefits from clean stripping and water changes; Cut into chlorinated water, then transfer to Chrysal #2 solution, hold in cooler at about 33F.
Additional Comments: 2011 was the worst growing year I have ever experienced, beginning with record snowfall and record cold (February), followed by record rainfall (May), and record heat and drought (July and August). ‘Henry Eilers’ did well regardless.

 View images and tables on page 33-38 here.