Various species and selections of Achillea L. were grown for 2 to 5 years, depending on taxon, and evaluated for cut flower yield and quality. `Coronation Gold' yarrow (A. × `Coronation Gold') was productive for 5 years. Flower yield, average stem diameter, and stem length were smallest the first year, but no differences occurred between years 2 and 5. The highest percentage of stems > 50 cm long occurred on plants at the densest spacing. Yields were higher and stems longer for A. millefolium L. cultivars and A. ptarmica L. `The Pearl' in the second than the first year. A. millefolium `Kelwayi' and `Lilac Beauty' produced the highest yield while `Heidi' and `Sawa Sawa' produced the longest stems. Yields of all cultivars of Galaxy hybrids (A. taygetea Boiss. & Heldr. × A. millefolium) increased over 4 years of harvest. Stems were longer and flower diameters were larger after the 2nd year for all cultivars but `The Beacon'. `Salmon Beauty' had the highest yield, but yield of `Appleblossom' did not increase after year 2.
Various field-grown specialty cut-flower species were subjected to full sun or 55% or 67% shade treatments for 2 to 3 years. Plants grown in shade had longer flower stems than those grown in ambient irradiance; however, yield (flower stems per plant) was species-dependent. Yield of Centaurea americana Nutt. `Jolly Joker', an annual speices, and Eryngium planum L., a perennial, declined linearly with each reduction in irradiance. However, yield of Echinops ritro L. `Taplow Blue', a perennial species, was higher in 55% shade than in ambient irradiance. Yield of transplants and tubers of Anemone coronaria L. `De Caen' were not affected by planting material (transplants or tubers). Plants grown under 67% shade had the longest stems starting 3 weeks after the beginning of harvest and the difference persisted for an additional 4 weeks regardless of planting material. A quadratic decline in yield in three of four cultivars of Zantedeschia Spreng. occurred as shade increased, but yield was similar for ambient and 55% shade. Scape length and spathe width increased as shade increased, although some cultivars were more responsive than others.
A.M. Armitage and Meg Green
The University of Georgia trial garden has been in existence since 1982, and the method of evaluation and distribution of taxa has evolved over the years. Annual and perennial taxa are evaluated systematically, over the entire season, providing season-long summaries for each one. Annuals are evaluated every 2 weeks, and scores are based on plant performance, including foliar health, flower numbers and the appearance of disease and insect damage. Perennials are evaluated similarly, however flowering time, flowering persistence and height in the landscape are also noted. Summaries for each taxon are presented in tabular and graphic form. Many new crops have been evaluated and introduced to the floriculture industry. New crops are placed in the horticulture gardens and evaluated by garden personnel and by commercial growers and landscapers. Plants have been distributed free of charge to propagators and growers, resulting in rapid market acceptance of successful taxa.
A.M. Armitage and J.M. Laushman
Various bulbous species were planted during the fall and winter in an attempt to extend harvest periods of cut flowers. In the first year, late planting resulted in later flowering, but shorter stems and reduced yield than early planting; however, some responses were species specific. No differences in flowering due to initial planting times occurred in the subsequent 2 years, regardless of species tested. Anemone coronaria L. and Acidanthera murielae Hoog. ex Perry were productive for 1 year only, but Allium sphaerocephalum L., Brodiaea laxa Wats., and Crocosmia × crocosmiiflora (V.Lem. ex E. Morr.) N.E. Br. were productive for 2 to 3 years. The peak harvest for anemones was 3 to 5 weeks from beginning of harvest, depending on cultivar, and 10 to 20 days from beginning of harvest for crocosmia. Anemone `Mona Lisa' produced longer stems and larger flowers and flowered earlier than `De Caen'.
A.M. Armitage and J.M. Laushman
Bulbous roots of Kansas gayfeather or liatris (Liatris spicata Wind.), tuberose (Polianthes tuberosa L.), and Dutch iris (Iris × hollandica) were planted between Nov. 1986 and Mar. 1987. Late planting extended harvest times and resulted in highest yields and longest stem lengths for Liatris spicata and Polianthes tuberosa, but. results were cultivar-dependent with Iris × hollandica hybrids. Yield was highest for all cultivars of Dutch iris except `White Bell' when bulbs were planted in December. Late planting extended harvest time but reduced yield for all cultivars except `White Wedgwood'. No differences due to planting time occurred after the first season for liatris and tuberose, but both species had higher yields the years after initial planting and may be left undisturbed for at least 3 years. Iris flowers were destroyed by late frosts in two successive years and longevity could not be determined. The yield and stem length were optimum for Liatris 10 to 15 days from beginning of harvest, 4 to 5 weeks for single-flowered tuberose, and 5 to 6 weeks from start of harvest for double tuberose. Stem length of tuberose increased over the seasons, regardless of cultivar.
A.M. Armitage and P.M. Gross
A copper hydroxide formulation (0%, 3.5%, 7%, 11% Cu) was applied to plug trays before sowing seeds of Impatiens ×hybrida L. `Accent Red', Pelargonium ×hortorum Bailey `Scarlet Elite', and Petunia ×hybrida Hort.Vilm.-Andr. `Ultra White' to investigate the influence of the formulations on ease of transplant, root growth, and shoot growth. These factors also were investigated in Cu-treated seedling plugs held past optimal transplanting stage. Root spiraling and seedling height at transplant were reduced for all taxa grown in Cu-treated trays, regardless of concentration, compared to seedlings from nontreated trays. Root weight and shoot weight responses to Cu treatments at transplant and at flowering varied among taxa. Mature heights of all taxa were unaffected by Cu treatment; however, flowering date was delayed for impatiens and geraniums transplanted at optimal time from Cu-treated trays. In general, petunias displayed little response to Cu treatment. Root spiraling was reduced and plugs were removed more easily from Cu-treated than from control trays stored for 2 weeks in the greenhouse, but flowering time was delayed for 12 days for impatiens and petunias and 21 days for geraniums, regardless of Cu concentration.
M. P. Kaczperski and A. M. Armitage
The effects of differing storage conditions prior to transplanting were examined for Salvia splendens `Red Hot Sally', Impatiens wallerana `Super Elfin White', Viola × wittrockiana `Universal Beaconsfield' and Petunia × hybrida `Supercascade Lilac'. Plug-grown seedlings were stored for 0, 1, 2 or 3 weeks at 5C or 10C and irradiance levels from incandescent bulbs at 0, 2 or 12 μmol s-1 m-2. A second group of plants were stored at 18C and irradiance from fluorescent bulbs at 105 μmol s-1 m-2 for the same time period. Temperature was more important than irradiance in maintaining plant quality over the storage period. Impatiens and salvia could be stored successfully for a minimum of 2 weeks at 5 or 10C with no appreciable loss of quality, petunia and pansy up to 3 weeks. Seedlings of all species showed diminished quality when stored longer than 1 week at 18C. After storage, petunias stored at 18C flowered sooner than those stored at 5 or 10C. However, these plants were single stemmed, with long internodes and few flowers while those plants stored at 5 or 10C developed multiple branching and a short, compact growth habit at flowering.
M.P. Kaczperski and A.M. Armitage
The effects of storage conditions before transplanting were examined for Petunia × hybrida Vilm. `Supercascade Lilac', viola × wittrockiana Gams `Universal Beaconsfield', and Salvia splendens F. Sellow ex Roem. & Schult `Red Hot Sally'. Plug grown seedlings were stored for 0, 7, 14, or 21 days at 5 or 10C and with continuous irradiance levels from incandescent bulbs at 0, 2, or 12 μmol·m-2·s-1. A second group was stored at 18C with irradiance from fluorescent bulbs at 105 μmol·m-2·s-1 and a 16-hour photoperiod for the same durations. Temperature was more important than irradiance in maintaining a commercially acceptable plant during the storage period. Petunia and pansy could be stored successfully for 21 days at 5 or 10C with no appreciable loss of quality; salvia could be stored for a minimum of 14 days. Seedlings of all species elongated excessively when stored >7 days at 18C and 105 μmol·m-2·s-1 irradiance. After 14 days of storage, petunias stored at 18C flowered sooner than those stored at 5 or 10C but time in a production environment (days to flower - days in storage) was similar for petunias stored at 5 or 18C.
James M. Garner, Starla A. Jones and Allan M. Armitage
Two studies were conducted to determine the influence of decapitation (pinch treatment) and photoperiod treatments on stem length, days from planting to harvest, and flowering stem yield in two delphinium cultivars. Plants of Delphinium ×belladonna Hort. ex Bergmans `Völkerfrieden' received a hard pinch (removal of apex and all stem and leaf tissue associated with leaves ≤10 cm), soft pinch (removal of apex and all stem and leaf tissue associated with leaves ≤4 cm), or no pinch. Plants of the D. elatum L. `Barbara' series were grown under either long- or short-day photoperiod, each treatment with or without receiving a soft-pinch. Time from planting to harvest was longer in pinched plants than in nonpinched plants of both cultivars regardless of photoperiod. Flowering stems were longer in hard- and soft-pinched plants of `Völkerfrieden' compared to nonpinched plants, and with `Barbara', stem length of pinched plants was either longer or similar to that of nonpinched plants regardless of photoperiod. At 30 days after the commencement of harvest, yield of flowering stems for hard-pinched plants of `Völkerfrieden' was higher than that for nonpinched plants, but yield from soft-pinched plants was similar to that for those not pinched. Stem yield for `Barbara' was higher for pinched plants under the long-day photoperiod, but under short days, yield from pinched plants was similar to that for those not pinched. Long days appear to increase yield and reduce production time in delphinium cultivars. Commercial benefits may be realized by growing nonpinched plants for earliness and pinched plants for longer stems and higher yield.
Natalia K. Hamill, A.M. Armitage and S. L. Anderson
As part of the New Floriculture Crop Program at the University of Georgia, a research project was initiated in Fall 2004 to determine production protocols for forcing woody shrubs in the greenhouse. The influence of cooling on greenhouse forcing of three woody taxa (Caryopteris ×clandonensis `Sunshine Blue', Leycesteria formosa `Golden Lanterns' and Sambucus nigra `Black Lace') was evaluated. Dormant rooted liners (7 cm) were received in November 2004 and were cooled for 0, 6, or 10 weeks at 1.7–4.4 °C. With 0 weeks cooling, Caryopteris ×clandonensis `Sunshine Blue' never reached an acceptable finish stage. With 6 weeks cooling, plants were not of sufficient quality to be saleable; however with 10 weeks cooling, plants finished in 7 weeks in the greenhouse. With 0 weeks cooling, Leycesteria formosa`Golden Lanterns' was saleable in 13 weeks. With 6 weeks cooling, plants finished in 7 weeks. With 10 weeks cooling, plants finished in 8 weeks. With 0 weeks cooling, Sambucus nigra `Black Lace' never reached a saleable stage. With 6 weeks cooling plants were saleable in 11 weeks; with 10 weeks cooling plants finished in 6 weeks. The data suggest that cold is necessary for greenhouse forcing of Caryopteris and Sambucus, and that 10 weeks of cold resulted in the shortest production time. Data suggest that 6 weeks cooling of Leycesteria resulted in the shortest production time; however cooling is not necessary to produce a finished plant of good quality.