September 1980 Horticulture Series No. 26 Auburn University Agricultural Experiment Station R. Dennis Rouse, Director Auburn University, Alabama .p RESEARCH RESULTS FOR ORNAMENTAL HORTICULTURISTS Horticulture Series No. 26 Auburn University Agricultural Experiment Station R. Dennis Rouse, Director September 1980 Auburn, Alabama CONTENTS Page 1. Use of Sewage-Refuse Compost in the Production of Ornamental Plants. Kenneth C. Sanderson....................... 1 2. Effect of Dikegulac Sodium on Vegetative Shoot Growth of Greenhouse Azaleas, Rhododendron cv. 3. California Nurseries: Lih-Jyu Shu and Kenneth C. Sanderson. 17 Innovations, Management and Problems. Kenneth C. Sanderson 4. 5. .......... .......................... Kenneth C. Sanderson . . 27 28 A New Chemical Pinching Agent for Ornamentals. A Sabbatical View of Instruction at the Largest Ornamental Horticultural School in the United States. Kenneth C. Sanderson ....... .34 Use of Sewage-Refuse Compost in the Production of Ornamental Plants Kenneth C. Sanderson Nature of Work: Gouin (9) has pointed out that producers of greenhouse and nursery crops are ideal users of waste composts. less a problem. Both heavy metals and threats to human health are The greenhouse-nursery industry is also ideal because it uses large quantities of organic materials in their plant growing media (21). Traditionally the organic material has been sphagnum peat moss and several peat-based media (1, 3, 4) have been developed for use on ornamental plants. Sphagnum peat moss has become expensive and difficult to obtain, therefore substitutes involving residues have been tried (10 12). For plant disease, insect and weed control, media for ornamental plants is routinely steam or chemically pasteurized and this procedure would eliminate human pathogens (1). Prior to planting, ornamental media is also amended with various chemicals, i.e. limestone, that could influence human pathogens and heavy metal availability. A wide variety of plants with various tolerances and needs for many of the heavy metals are grown by the ornamental industry. Leep and Eardly (12) found that metal rich sewage medium had no determinental seedlings growth; indeed, in effect on plans tree maple, Acer pseudo-platanus L., most cases the seedlings from high sludge treatments performed significantly better than those grown in unamended potting medium. these plants was not found to be excessive. Also, the total metal burden in Large quantities of water and fertilizer are applied to ornamental plants to facilitate rapid growth and these applications may have an effect on heavy metal availability and accumulation. composts in ornamental production Dilution is workers. Using waste would involve dilution of any toxic pollutants. not an acceptable solution to pollution problems according to some dilution in the soil is far more acceptable than air or water However, dilution (2). 2 Research at the Auburn University Agricultural Experiment Station has primarily been concerned with a sewage-refuse compost. This compost was prorags, duced by the City of Mobile, Alabama by removing most of the metal, and large items from municipal refuse and garbage, hammermilling, flaming to remove flexible plastic, spraying with raw sewage, and composting for 1216 weeks in windrows. The "finished" compost had a dark brown granular 1/ appearance with much flexible and rigid plastic visible. Self found it contained 15 to 20% ground glass, 10 to 20% plastic and 20% moisture by weight. The glass did not present a problem in handling. Spurway analysis of dilute acetic acid extracts revealed 0-5 ppm NO , 3 0-1 ppm P, 20-20 ppm K and 100-150 ppm Ca. read 30-86 mhos (1:5 dilution). The pH was 8.4 and soluble salts Ammonium acetate extraction for exchangeable The bases revealed 0.9% total N, 0.2% P, 6.0 meg/100g K, 42.4 meg/lOOg Na. compost had a C/N ratio of 38.5, an exchange capacity of 13.7 meg/100g, 34.2% total carbon and negative tests for NH 4 , NO 3 , Cl, and SO spectrographic analysis revealed the presence of Pb, Sn, ions. Cu, Mn, X-ray Fe, and Zn. In media experiments, the sewage-refuse compost was mixed 1:1 by volume with a silt loam soil, amended with superphosphate and steam pasteurized. A 1:1 by volume sphagnum peat moss media was used as a comparison in most experiments. Generally pH was adjusted with dusting sulfur for compost media and limestone for the sphagnum peat moss media. Additional calcium was added in the form of gypsum to compost media. A high analysis fertilizer was used on a regular basis either weekly (400 ppm N, 88 ppm P, 166 ppm K). 176 ppm P, 332 ppm K) or constant (200 ppm N, Standard commercial cultural procedures were followed for specific crops. I/ Personal communication Dr. Raymond L. Self, Auburn University Ornamental Horticultural Field Station, Mobile, Al Greenhouse crops in sewage-refuse media Much of the research on greenhouse crops has considered chrysanthemums grown as standard cut flowers and potted plants. Early in their growth chrysanthemums grown in sewage-refuse media exhibited a marginal necrosis on their lower leaves. This injury was relatively unimportant in standard cut However, Foliar flower production because the flowers are cut above the injured area. this injury would greatly reduce the quality of potted chrysanthemums. analysis of cv. Giant Indianapolis No. 4 leaves from the fifth and sixth node (counting from the base of the plant) revealed excessive levels of P, Mn, and Zn in plants grown in the sewage-refuse medium (Table 1). Mg and Fe were below the ranges reported for optimum growth (5). K, B, Levels of Potted chrysanthemum leaves of cv. Sunstar plants grown in the sewage-refuse medium showed excess concentrations of P, Ca, and Zn while N, Fe, were low. Gogue and Sanderson (8) found high foliar K, Cu, and Cu concentrations B, and Zn in leaves of the standard chrysanthemums cvs. CF No. 2 Good News and Improved Albatross grown in sewage-refuse medium. These workers also observed a marginal injury Purvis (15) has noted that B is on lower leaves and attributed it to B (7). the most likely element to be phytotoxic in compost. Gogue (6) was unable to produce injury with Zn at foliar concentrations higher than those observed in plants grown in sewage-refuse medium. The height flowering, stem weight, and flower diameter of chrysanthemum plants grown in sewage-refuse medium was less than that of plants grown in the sphagnum peat moss medium. in Gogue and Sanderson (8) found that plants grown sewage-refuse had smaller flowers, less dry weight and shorter stems than Negative correlations of these Na, and Zn concentrations were plants grown in a sphagnum peat moss medium. Al, B, growth parameters with foliar K, Cu, also reported by these workers. Snapdragons, Antirrhinum majus L. were grown in sewage-refuse compost amended medium because of their sensitivity to soluble salts and high boron requirements. Early in their growth, plants grown in sewage-refuse medium Height, flower exhibited chlorosis, burning and spotting of their lower leaves. head length, and stem weight/length ratio (a measure of stem strength) of plants grown in sewage-refuse medium was only slightly less than plants grown in sphagnum peat moss medium (Table 2). The fresh weight of plants grown in compost Data was was 22% less than that of plants grown in sphagnum peat moss media. averaged from 2 experiments involving Group II (winter flowering) cultivars in Experiment 1 and Group IV (summer flowering) in Experiment 2. Easter lilies, Lilium longiflorum Thumb., were tested in sewage-refuse compost because of their high pH (6.8-7.2) and Ca requirements. Precooled bulbs of cvs. Ace and Nellie White grown in sewage-refuse medium were taller and averaged more flowers than plants grown in sphagnum peat moss medium (Table 2). Media were amended with 12.0N-2.6P-5,OK fertilizer and adjusted to pH 6.8 prior to bulb planting on January 2. weekly basis. The horticulture geranium Pelargonium x hortorum L. H. Bailey produced less dry weight when grown in sewage-refuse medium than when grown in sphagnum peat moss amended medium (Table 2). comparable. 'Blaze', 'Eleanor', 'Dark Red Irene', and 'Summer Cloud' were grown in Visually the plants in the 2 media appeared Liquid fertilization was also used on a this experiment and their data were averaged. The production of woody ornamentals in containers When sewage-refuse compost was combined with sand, bagasse, perlite or vermiculite to produce soil-less media, woody plants exhibited chlorosis 6 months after potting (17). The chlorosis was attributed to rapid decomposition of the compost, slow release rate of a urea formaldehyde fertilizer, high soluble salts and high pH (17). The immaturity of the compost, low nitrogen, high soluble Foliar salts and a high pH resistant to change had been noted previously (19). element concentration and growth of plants grown in a 1:1 sand base medium for 1 year revealed that the various species performed differently with sewage refuse or sphagnum peat moss amendment (Table 3). Leaves of Ilex and Viburnum plants sphagnum contained more N when grown in sewage-refuse medium than when grown in peat moss medium. Rhododendron moss medium. plants accumulated more foliar N in sphagnum peat Both Ilex cornuta 'Matthew Yates' and Rhododendron plants had higher foliar K concentration when grown in sewage-refuse medium, however foliar K levels for Juniper plants were higher in sphagnum peat moss medium. With the exception of considerably higher foliar Ca concentrations in Ilex cornuta 'Matthew Yates' and Juniper plants grown in sewage-refuse medium, foliar Ca concentrations were comparable in both media. more foliar Mg. Sphagnum peat moss grown plants generally contained Foliar concentration of N, P, K, Ca, and Mg for Rhododendron cv. plants grown in both media species contained adequate Ca concentrations but none of the other elements in by Smith (20), Burkw. & Skipw., conferta Parl. any of the 5 test plants were in the ranges judged sufficient With the exception of the height of Viburnum burkwoodii Hort. spread of Ilex crenata Thumb. and Rhododendron 'Evensong', 'Hetzii' and dry weight of Juniperus sphagnum peat plants grew better in moss medium than in sewage-refuse medium (Table 3). 'Matthew Yates' All growth parameters for Ilex cornuta Lind. & Paxt. grown in were greater when the plants were sphagnum peat moss media. 6 Sanderson and Martin (18) demonstrated that the nutrition difficulties observed early in the growth of woody ornamentals grown in sewage-refuse medium could be overcome by the use of constant or bi-monthly application of high analysis (25N-4.4P-8.4K) fertilizer. In their work, dry organic and inorganic fertilizer did not produce as favorable growth results as liquid regimes in a soil:perlite medium amended with either sewage-refuse compost or sphagnum peat moss. weight and total plant height of Ilex cornuta Lidl. 'Burfordii' and Thuja Dry occidentalis L. were greater in sewage-refuse-amended medium than in sphagnum peat moss-amended medium. Sewage refuse compost as a mulch Large quantities of sewage-refuse could be used as mulches in the landscape, production of field-grown woody plants and on public lands such as highways and parks. Mulches can conserve moisture, reduce weeds, prevent wide flucuations Sewage-refuse compost mulches in soil temperature, and influence soil nutrients. have produced no apparent differences in the growth and flowering of Petunia x hybrida Hort. Vilm-Andr. (16) and Chrysanthemum x morifolium Ramat. (14). Appearance, odor, and possible health hazards would limit this compost's use in most landscape situations. Sewage-refuse compost mulch was comparable in weed coverage but caused greater plant losses than sawdust mulches in the field production of woody ornamentals (Table 4). Four months after mulch application, liners mulched with sewage-refuse compost averaged 20-27% losses whereas no mulch and sawdust mulch plants averaged 4-6% losses. Buxus harlandii Hance, Viburnum burkwoodii Hort. Burkw. & Skipw. and Rhododendron 'Rose Banner' plants suffered 13-73% losses when mulched with sewage-refuse (Table 5). Ilex cornuta Lindl. & Pact. 'Matthew Yates', Juniperus chinensis L. 'Pfitzerana', Juniperus conferta Parl. and Thuja occidentalis L. 'Pyramidalis' plants had 0-20% and 0.7% losses, respectively, Generally, sewage-refuse mulches with sewage-refuse and sawdust mulches. increased soil pH, P, K, and Ca; however sawdust mulches caused a statistical reduction in soil pH and Ca. Growth of plants mulched with sewage-refuse but was less than that of sawdust-mulched exceeded that of unmulched plants plants (Table 4). The increase in soil pH and nutrients with sewage-refuse mulches was even more evident in experiments conducted on flat and slope sites located onan Interstate highway (Table 6). Soil under sewage-refuse mulch contained more P, K, Ca, and Mg than unmulched soil and soils mulched with turffiber, pecan hulls, pine straw or sawdust. Nitrogen content of Forsythia intermedia Zabel. leaves from plants mulched with sewage-refuse (2.71%) exceeded that of leaves of no mulch (2.35%), turffiber (2.28%), pecan hulls (2.19%), pine straw (2.41%) and sawdust (2.36%) plants. With the exception of pecan hulls, the soil moisture content under the various mulches was similar.Mulching also did not seem to affect soil temperature. Sewage-refuse mulches exhibited the greatest resistance to Sewage-refuse mulches' resistance to erosion erosion of any of the mulches tested. supports Scarsbrook et. al (19) recommendation that sewage-refuse compost be used on highway cuts and fills. Conclusions: The greenhouse-nursery industry is uniquely qualified to utilize sewage-refuse compost. In the production of ornamental plants there is a need for large quantities The formulation and use of sewageThe standard industry practice of of organic matter to formulate various media. refuse compost would be environmentally safe. media pasteurization would eliminate most health hazards not eliminated by composting. Sewage-refuse compost contains many nutrients which ornamental plants utilize and heavy metals do not present serious problems in the production of some ornamental plants. Both greenhouse and woody ornamental plants have been successfully grown in media amended with sewage-refuse compost. A marginal leaf burn was observed in some herbaceous plants grown in sewage-refuse amended media and boron has been identified as the cause of this toxicity. High pH, high soluble salts, and other elements may require attention. reduce or eliminate toxicity problems. Leaching and cultural practices may Sewage-refuse compost mulches have As a mulch sewage- been shown to have a beneficial effect on highway plantings. refuse compost controls weeds, resists erosion, and increases soil nutrients. At present, economics are the greatest deterrent to sewage-refuse compost use. It's simply cheaper to bury, burn or dump our wastes. In the future, changes in laws, traditions and habits; and economic incentives may make compost use more feasible. However, the future will also bring an increasing understand- ing that we have no alternative except to utilize all our resources, including wastes, in the most judicious manner. Composting is a judicious use, nonethe- less the energy value of waste may preclude all uses except energy generation. 9 Table 1. Foliar element concentration of two chrysanthemum cultivars grown in sewage-refuse- and sphagnum peat moss-amended media Element concentration Giant Indianapolis # 4 Sewage-refuse Sphagnum peat 4.02 0.88 5.43 1.94 0.68 780 114 Sunstar Sewage-refuse 4.15 0.72 5.60 3.15 0.35 390 146 23 450 76 1,200 320 Sphagnum peat 4.60 1.25 4.97 2.02 0.77 216 130 17 278 57 1,140 67 N% P% 5.20 0.62 6.60 2.02 0.22 900 226 K% Ca% Mg% Mn, ppm Fe, ppm Cu, ppm Al, ppm B, ppm Na, ppm Zn, ppm 36 338 179 550 494 12 332 87 660 320 10 Table 2. Growth of snapdragons, Easter lilies and geranoums in sewage-refusem -r_ r _ 9 ~__ ___L1_ and sphagnum peat moss amended media ~ ~'I + _~C _._ _ _ ~_- _ _ _ _ _ Crop .. Media 1:1 (v/v) Sewage-refuse: Soil Sphagnum peat moss: Soil Snapdragons Height (cm) Fresh weight (g) Flower head length (cm) Stem weight/length vation (g/cm) y Easter lilies Height (cm). No. flowers per plant x Geraniums 91.4 48.3 22.9 0.3 94.3 62.3 19.8 0.3 41.9 4.7 38.9 5.0 Dry weight (g) 15.7 20.4 Z Means based on 10 plants each in Exp. 1 cvs. Jackpot, Twenty Grand and Sakata 148 and Exp. 2 Potomac Pink and Potomac White. Means based on 10 plants each, cvs. Nellie White and Ace. XMeans based on 16 plants. Table 3. Foliar element concentration and growth of woody ornamentals grown in sphagnum peat moss- and sewage-refusePlant amended media Plant growth Per cent by weight N P K Ca Mg Height (cm) Spread (cm) Dry weight (g) Ilex cornuta cv. Matthew Yates Sand: sphagnum peat moss z 1.70 1.84 0.04 0.04 0.51 0.56 0.69 0.92 0.20 0.09 24.9 22.9 23.9 21.9 25.8 22.7 Sand: sewage-refuse compost Ilex crenata cv. Hetz Sand: sphagnum peat moss Sand: sewage-refuse compost Juniperus conferta Sand: sphagnum peat moss Sand: sewage-refuse compost Rhododendron cv. Evensong 1.81 1.86 0.04 0.05 0.53 0.52 1.32 1.33 0.27 0.19 30.0 26.2 23.5 28.7 38.8 32.7 1.50 1.50 0.05 0.06 0.44 0.38 0.54 0.72 0.08 0.05 33.0 28.0 39.1 29.0 57.9 60.0 Sand: sphagnum peat moss Sand: sewage-refuse compost Viburnum burkwoodi Sand: sphagnum peat moss Sand: sewage-refuse compost 1.61 1.46 0.05 0.05 0.32 0.43 0.59 0.60 0.10 0.08 20.7 19.2 25.2 20.9 17.6 18.2 1.64 1.81 0.05 0.04 0.51 0.51 0.71 0.72 0.08 0.06 32.5 36.8 25.7 25.2 21.6 19.1 z Sphagnum peat moss media were amended with dolomitic limestone to adjust pH to 5.0 (Rhododendron, flex) and 6.0 (Juniperus, supply Ca. Viburnum). Sulfur was used to adjust pH of sewage-refuse media. Gypsum added to sewage refuse media to 12 Table 4. Per cent weed coverage and plant loss after 4 months, soil pH and nutrient content and plant growth after 1 year under various mulches Mulch Per cent Per cent. Soil Soil elements Plant Weed coverage plant loss .J4 Kg/hectare P K Ca 437a 300c 298c 389ab 395ab height (cm) 76 86 97 79 76 Plant spread (cm) 66 89 107 79 84 None 2.5 cm Sawdust 5.0 cm Sawdust 2.5 Sewage-refuse 57a l6bc 4c 28abc 6 4 5 20 27 6.3ab 142a lO4ab 6.Ob 6.Ob 6.4a 128a 113a 57b 45b 246a lO2ab 5 cm Sewage-refuse 20abc 6.5a. 231a 136ab LV ~L ~L ~U V1I~L Z ~U ~ Y Mean separation in columns by Duncan's multiple range test, 5% level. 13 Table 5. Per cent plant loss of various woody ornamentals 4 months after mulching-with sewage-refuse 'compost and sawdust Plant Sewage -refuse 2.0'5 ,-:, cm 5.0 cm 73 13 20 0 33 0 34 Sawdust 2.5 cm 0 0 0 0 0 0 20 5.0 cm 13 0 7 0 0 7 12 Buxus harlandii Ilex cornuta'Matthew Yates' Juniperus chinensis 'Pfitzerana' Juniperus conferta Rhododendron? Rose Banner' Thuja occindentalis 'Pyramidalis' Viburnum burkwoodii - 67 0 0 7 13 13 40 14 Table 6. Effect of various highway mulches on soil pH, nutrients, moisture and temperature -------------------------lp-"'IR -"IR -- t r- Mulch z Soil x pH P Nutrients K Ca (Kg/hectare) Moisture Mg per cent Temperature oC None Turffiber Pecan hulls Pine straw Sawdust Sewage-refuse compost 6.1 6.0 5.9 6.1 5.9 6.8 22 21 22 22 18 29 104 93 190 86 95 201 804 837 780 834 888 1200 102 101 104 104 100 108 60 62 67 63 62 62 19.6 19.6 19.8 19.6 20.1 19.7 Samples for soil analysis were taken to a 15-20 cm depth with a soil tube after removing the mulch which had been applied 11 months earlier. Y Moisture reading made with gypsum blocks located in the center of 8 mulch plots at a 15 cm depth. X 6 months data (July-January). (July-January) with a telethermometer Mean of weekly readings for 6 months from thermister probes located in the center of 8 plots at 15 cm depth. 15 Literature Cited 1i. Baker, K. F. 1957. The U. C. system for producing healthy container-grown Sta. Manual 23. 332 p. plants. Calif. Agri. Exp 2. Bohn, H. L. and R. C. Cauthorn. 1972. Pollution: the problem of misplaced waste. Am. Sci. 60:561-565. 3. Boodley, J. W. and K. S. Sheldrake. 1972. Cornell peat-lite mixes for commercial plant growing. Cornell Univ. Plant Sci. Info. Bul. 43. 4. Conover, C. A. 1967. Soil mixes for ornamental plants. Florida Flower Grower. 4:1-4. 5. Criley, R. A. and W. H. Carlson. 1970. Tissue analysis standards for various floricultural crops. Florists' Rev. 146(3771):19,20,70-73. 6. Gogue, G. J. 1970. Boron, sodium and zinc tolerance of chrysanthemums grown in processed garbage amended media. MS Thesis. Dept. of Horticulture, Auburn University, Auburn, AL 105 p. 7. and K. C. Sanderson. 1973. Boron toxicity of chrysanthemums. HortScience. 8:473-475. 8. .and . 1975. Municipal compost as a medium amendment for chrysanthemum culture. J. Amer. Soc. Hort. Sci. 100:213-216. 9. Gouin, F. R. 1977. Screened sludge compost potting mixes. News Release Allied Landscape Industry. July. 8 p. 10. Hoitink, A. J. and H. A. Poole. 1979. Factors that affect bark composting. Am. Nurseryman. July. p. 23, 189-193. 11. Kofranek, A. M. and 0. R. Lunt. 1975. Mineral nutrition. p. 38-46. In Div. A. M. Kofranek and R. A. Larson (eds.). of Agric. 12. Lepp, Sci. Univ. of Calif. Pub. Eardley. 1978. Growing azaleas commercially. 4058. Growth and trace metal content of soil amended with sewage sludge. N. W. and G. T. European sycamore seedlings grown in 16 13. Nelson, P. V. 1972. Greenhouse media. The use of co funa, floramull, pinebark, and styromull. N. C. Agric. Exp. 14. Sta. Bul. 206. Orr, H. P., K. C. Sanderson and W. C. Martin, Jr. Comparison of processed garbage, sawdust, pine straw in mulching garden chrysanthemums. Orn. Res. So. Nurserymen's Assoc. 11:19. Ann. Rept. 15. Purvis, D. and E. J. Mackenzie. 1974. Phytotoxicity due to boron in municipal compost. Plant Soil. 40:231-235. 16. Sanderson, K. C., H. P. Orr and W. C. Martin, Jr. 1967. Comparison of processed garbage, sawdust and pine straw in mulching petunias. Ann. Rept. Orn. Res. So. Nurserymen's Assoc. 11:20. 17. R. L. Self, H. P. Orr and W. C. Martin, Jr. 1969. Utilization of processed garbage-sludge as a media additive in the production of woody plants in containers. Proc. So. Nurserymen's Res. Confr. 13:14-15. 18. Sanderson, K. C., and W. C. Martin, Jr. 1974. Performance of woody ornamentals in municipal compost medium under nine fertilizer regimes. 9:242-243. 19. Scarsbrook, C. E., A. E. Hiltbolt, K. C. Sanderson, D. G. Sturkie, and H. P. Orr. 1970. Conservation of municipal resources. U. S. Dept. Health, Ed. and Welfare, Public Health Serv. Consumer Protection and Environ: Health Service Bureau of Solid Waste Management. 113 p. HortScience 20. Smith, E. M. 1976. Nutrition research foliar analysis of woody ornamentals. Amer. Nurseryman. January 15. p. 13-15. 21. White, J. W. 1974. 73-74. Criteria for selecting greenhouse media. Florists' Rev. 152:28-30, Publications: 1. Sanderson, K. C. 1980. Use of sewage-refuse in the production of ornamental plants. HortScience: 15(2) 173-178. 17 Effect of Dikegulac Sodium on Vegetative Shoot Growth of Greenhouse Azaleas, Rhododendron cv. Lih-Jyu Shu and Kenneth C. Sanderson- Nature of Work: Dikegulac sodium, the sodium salts of 2,3:4,6-bis-0-(l-methylethylidenea-L xylo-2-hexulofuranosonic acid), has been tested as a pinching agent on Rhododendron sp. (1, 4, 5, 6, 7, 8, 10, 11, 12, 14, 15). Researchers reported that dikegulac sodium sprays destroy apical dominance and induce the production of axillary shoots (2, 4). Delayed plant growth (5, 10, 14, 15) as well as retardation (4, 10) has raised serious questions concerning the use of dikegulac sodium in the production of Rhododendron cv. Heursel (11) has reported that the growth delay might last 6 to 24 weeks depending on the number of applications, plant metabolism and environmental conditions. Vigorous growth generally was restored 6 to 7 weeks after a single application under a good growth environment (11). Cohen (6) also has noted that dikegulac sodium increased branching per stem on Rhododendron with no effect on shoot length 7 weeks after application. The purpose of the present work was to define the delayed growth effect of dikegulac sodium on vegetative shoot growth of greenhouse azaleas, Rhododendron CV. i/ Appreciation is expressed to Hoffmann- LaRoche, Nutley, N. J. for their support of this investigation; Yoder Brothers, Fort Myers, FL and Blackwell Nurseries, Semmes, AL for furnishing the plants; and R. M. Patterson and J. C. Williams, data analysts, Auburn University, AL for statistical assistance. 18 Plants, 25 x 25 cm in size of the azalea cv. Kingfisher, 15 x 20 cm in size of azalea cv. Alaska, Red Gish and Red Wing were potted in 15.0 x 11.3 cm clay pots containing Canadian sphagnum peat moss amended with 1.48 Kg/m3 each of dolomitic limestone and gypsum. Fertilization consisted of applying 25-10-10 soluble fertilizer (containing 25.0% N, 4.4% P and 8.2% K) at the rate of 2.5 g/l. Approximately 120-180 ml of fertilizer Iron solution were applied to the plant medium of each pot every 2 weeks. sulfate (1.9 g/l) was added to the fertilizer solution to prevent iron deficiency. Appropriate insect and disease control methods were used whenPlants were grown in a glass greenhouse with a light Plants were sheared on December ever necessary. intensity of 48.5 klx (measured at noon). 23, 1978. A 0.50% dikegulac sodium spray was applied by a low pressure, for high volume sprayer to run-off on sheared plants on January 3, 1979, comparison with untreated sheared plants. spray material. No surfactant was added in the A randomized complete block design was used with 7 repli- cations, 3 plants per treatment (subsample) on cv. Kingfisher and 3 replications, 4 plants per treatment (subsample) on cv. Alaska, Red Gish and Red Wing. Photoperiod was supplemented during the night starting 2 weeks after treatment on January 17, 1979, by using constant light from incandescent bulbs (208.3 lux at the top of plants) from 10 p.m. to 2 a.m. Two shoots were chosen at random from each plant and tagged for shoot length measurement at various node positions on January 31, February 7 and February 14, 1979. Node positions were determined by beginning at the shoot apex. 1979. Total shoot number of each plant was recorded on February 14, Dikegulac sodium-treated plants exhibited the necrotic leaf tip and chlorosis reported by other workers (2,5,7,9,13,14,15) treatment on newly developing leaves. 3 to 4 weeks after 6 to The chlorosis disappeared in 19 8 weeks. It is suggested that this characteristic chlorosis may serve as Also, a difference in chlorophyll an activity indicator of dikegulae sodium. content of the leaves on dikegulac sodium-treated plants may provide a measurement of this chemical's inhibitory effect on plant growth. Number of producing shoots Four weeks after treatment, dikegulac sodium-treated plants produced new shoots at every node position from shoot apex to sixth (on cv. Alaska), the eighth (on cv. Kingfisher)and the ninth (on cv. Red Gish and Red Wing) nodes (Table 1). Whereas hand sheared plants (check) originated new nodes to only the fourth (on cv. Alaska), the fifth (on cv. Red Wing) and the sixth (on cv. Kingfisher and Red Gish) nodes. Shoot emergence from dikegulac sodium-treated plants averaged 4.0 (cv. Alaska), 5.1 (cv. Red Wing) and 5.2 (cv. Kingisher and Red Gish) nodes (Table 2). However, shoot emergence from check plants averaged 3.1 (cv. Alaska), 3.3 (cv. Kingfisher), 3.5 (cv. Red Wing) and 3.6 (cv. Red Gish) nodes. The mean number of nodes producing shoots on dikegulac sodium-treated plants exceeded that of check plants for the cv. Alaska, Kingfisher and Red Wing but not on Red Gish. New shoot length New shoots were shorter on the sheared plants treated with dikegulac sodium than on the check plants (Table 2). However, after 4 to 5 weeks, the increases in shoot length were not different from check plants except on cv. Kingfisher. At the 5 to 6 week interval shoot length increases on dikegulac sodium-treated plants were longer than the check plants for all the cultivars tested (Table 3). This suggested that dikegulac sodium did not exert a strong depressive effect on shoot growth 6 weeks after treatment. New shoot length varied by node position (Table 1). Dikegulac sodium- 20 treated plants produced uniform shoots from 1 to 4 nodes on cv. Alaska, 2 to 4 nodes on cv. Kingfisher, 1 to 5 nodes on cv. Red Wing and 1 to 2 and 4 to 5 nodes on cv. Red Gish plants; whereas, the check plants only produced uniform shoots from 1 to 2 nodes on cv. Alaska, Kingfisher and Red Wing at 4 weeks after treatment. Shoot length increased rapidly on cv. Alaska at 5 and 6 weeks so that dikegulac sodium-treated plant's shoot lengths were not as uniform as at 4 weeks after treatment. In contrast, shoot development became New shoot lengths of dikegulac uniform from nodes 1 to 3 on check plants. sodium-treated cv. Red Gish plants were uniformly produced at nodes 2,4 and 5 as well as at nodes I, 5 and 6 respectively 6 weeks after treatment; however, Shoots check plants produced different shoot lengths at every node. developing from the first node on dikegulac sodium-treated plants were never the longest shoots and shoots developing from node 5 were as long as node 1 shoots. Dikegulac sodium initially exerted a strong inhibitory effect on apical shoot development, so that new shoots could initiate from lower node positions. Apical dominance was rapidly restored on sheared plants and re- sulting new shoots initiated near the shearing point confirming Barrick and Sanderson's work (3). Due to the small number of shoots developed from nodes 6 to 9 the means do not represent the actual shoot lengths observed. Occasionally, a shoot developed at nodes 6 to 9 would be as long as any other shoots on the plant. Number of new shoots The total number of new shoots produced by the dikegulac sodium-treated plants exceed the number produced by the check plants (Table 2). agrees with other worker's findings (4,5,6,7,8,10,11,12,14,15). axillary shoot development resulted in a more compact plant. This result Also, increased 21 This work shows that a single 0.5% dikegulac sodium spray on sheared azalea plants does not exert a strong depressive effect on shoot growth. Furthermore, a greater number of shoots and shoots of more uniform length are produced at more and lower node positions thus yielding a more compact plant. Table Z/ 1,* Mean shoot length at dif ferent node positions on sheared azalea ev. Alaska, Kingf isher, Red Gish and Red Wing plants weeks after dikegulac sodium- and no (check) treatment. cv. Alaska New shoot length (mm) C Noweekhoot length (mm 4 to 6 Node at week cv. ReddWinh cvKiRed Gish ew shoot length (mm) at week at week Dikegulac sodium 0.50% 1 3 4 5 6 7 8. 4 10 216.4a l1.2a 16.4a 10.1a 3.8b 0.8b 0Ob .17.8bc 27.Oab 30.9a 20.7b 8.3cd 2.2d 0.Od 22.9bc 34.5ab 40.9a 26,63b 12.8cd 3.3de O.Oe 7Oc / 13. bd97 14.2a 11.3a 7.6b 2.4c 1.Oc 0.3c 10. Oc 9,5b 0.2a 17.7a 11,3b 4.1c 1.7c 0.6c 0,60C 2 11,6b 25.9a 24.Oa 14.4bk.b 6 eoc 2.2cd I.Od 0.040.3d 7.8b 14.8a 9.2bc 3.7cd 1,8d 0.7d 0. .04 S l213,3,11IL1,61.2 Check 1 2 3 4 5 6 7. S.E. 35.5a 37.5a 28.8b 12.2c 0.0d 2.1 47.7a 46.Oa 38.8a 16.8b 060C 3.3 54.2a 52.8a 43.7a 19.3b 0.OC 3.9 2B. 3a 31.3a 23.Ob 8.3c 4.04 M.e 0.Oe 1.1 34.7h 3 9.6a 32.Ob 1161C 5,4d 03e 0.Oe 1. 4 38.1b .a 35.5b 12 .2c 6.14 Or. 3e .0.0e 1.6 25.6b 29-.9a 21.3c 9.3d l.le 0.4e 0.Oe 1.4 l0,.3ba 18.a 5.b 5.k 16.1k 16,5bc 25e 6. 9cd6.5cd 1.3de 0.7e 0.Oe 2.0 29.8b 36.6a 22.7c 9.44 2.0e 1.4e 0.Oe 2.2 88b 12.5cd l.a 224a.6a 208 2.b 29. 3ba.a 74b 20o3bc 1.Oc 5.cd 9.3cd 8.5d 2.ee 06e 1.9e 1.6e 03 0.Oe 0O :2.m31.2324 33.56b 42.3a 25.4a 11.24d 2.1e 1.4e 0.Oe 2*6 18 335418 53 7l 28 0O 172.25 1.a 6.a 13ab 1lc 45d 1.d .d .4 55 36 22b 14b 6l l8 12 OO ... 8.a 14 0O d .4 4.a 47a 67 2O 51 0O -/ Node position counting from shoot apex. 1~ean separation in columns for treatment and week by Duncan's miultiple range test, 5% level. M 23 Table 2. Number of nodes with shoots, shoot length and total number of shoots on sheared azalea cv. Alaska, Kingfisher, Red Gish and Red Wing plants 4 to 6 weeks after dikegulac sodium treatment. No. node with z/ shoots at week 4 . Shoot lengt .(mm) at week4 ... cv. 5 Alaska 27.0 48.4 1.5 35.5 55.2 2.3 95.0 54.0 6.8 6. Total shoot no. at week 6 Treatment Dikegulac sodium 0.50% Check S.E. Dikegulac sodium 0.50% Check S.E. 4.0* 3.1 0.1 14.8 37.0 0.9 cv. Kingfisher 5.2 3.3 0.2 11.0 28.9 1.4 16.2 37.5 1.9 cv. Red Gish Dikegulac 20.8 41.7 2.4 95.8 58.0 6.2 sodium 0.50% Check S.E. 5.2 3.6 0.4 10.6 24.6 2.0 17.7 32.3 3.0 cv. Red Wing 23.0 36.7 3.1 126.6 76.6 3.4 Dikegulac * * * sodium 0.50% Check S.E. 5.1 3.5 0.0 11.5 32.0 0.7 19.6 39.4 0.2 26.6 44.7 0.8 73.3 38.9 0.9 z/ Data from 2 randomly selected shoots per plant, 3 replications. *,*' Significantly different from the check at the 5% and 1% level, respectively. 24 Table 3. Mean length increase (mm) of new shoots on sheared azalea cv. Alaska, Kingfisher, Red Gish and Red Wing plants between 4 to 5 and 5 to 6 weeks after dikegulac sodium treatment. Treatment Week interval 4 to 5 wk cv. Alaska Dikegulac sodium 0.50% Check S.E. 12.2 11.5 0.6 ev. Kingfisher Dikegulac sodium 0.50% Check S.E. 5.3* 8.6 0.7 ev. Red Gish Dikegulac sodium 0.50% Check S.E. Dikegulac sodium 0.50% Check S.E. 6.7 7.6 0.7 Qv. Red Wing 8.2 7.4 0.5 5% level. 7.0 5.3 1.0 5.4 4.4 0.4 4.5 4.2 0.6 8.5 6.7 1.3 5 to 6 wk *Significantly different from the check, 25 LITERATURE CITED i. Anonymous. 1975. Technical data sheet. Hoffmann LaRoche, Inc. Nutley, NJ. 2. Arzee, T., H. Langenauer,and J. Gressel. 1977. Effects of dikegulac, a Atrinal plant growth regulator. new growth regulator, on apical growth and development of three Compositae. Bot. 3. Gaz. 138(1):18-28. Barrick, W. E. and K. C. Sanderson. 1973. Influence of photoperiod, temperature, and node position on vegetative shoot growth of greenhouse azalea, Rhododendron cv. J. Amer. Soc. Hort. Sci. 98(4):331-334. 1975. 4. Bocion, P. F., W. H. de Silva, G. A. Huppi and W. Szkrybalo. Group of new chemicals with plant growth regulatory acitivity. Nature 258 (5531):142-144. 5. Breece, J. R., T. Furutaand H.. Z. Hield. 1978. Pinching azaleas Calif. chemically. Flower and Nursery Report for Commercial Growers. Ag. 6. Ext. Serv. Winter. p. 1-2. Cohen, M. A. 1978. Influence of dikegulac sodium, Off-Shoot-O and manual pinching on rhododendrons. Sci. Hort. 8:163-167. 7. De Silva, W. H., P. F. Bocion,and H. R. Walther. 1976. Chemical pinching of azalea with dikegulac. HortScience 11(6):569-570. 8. Finger, H. 1975. Atrinal, a new chemical pinching agent for azaleas. Gartenwelt 75(4):77-78. 9. Gressel, J. and N. Cohen. 1977. Effects of dikegulac, a new growth regulator, on RNA syntheses in Soirodela. Plant and Cell Physiol. 18(1) :255-259. 10. Heursel, J. 1975. Results of experiments with dikegulac used on azaleas (Rhododendron simsii Planch). (40: 849-857. Med. Fac. Landbouw. Rijksuniversiteit. Gent 26 11. Heursel, J. 1979. Invoed van de groeiregulator dikegulac op de scheutvorming, de verkoopdiameter, het bloeitijdstip en de bloemgrootte bij enkele cultivars van Rhododendron simsii Planch. (Azalea indica L.), Nededekubg Rijksstation Sierplantenteelt 43:1-89. 12. Kneipp, 0. 1977. Experience with chemical tipping of azalea. Deutscher Gattenbau 31(14):560-562. 13. Sachs, P. M.,-H. Hield,and J. DeBie. 1975. Dikegulac: a promising new foliar - applied growth regulator for woody species. HottScience 10(4):367-369. 14. Sanderson, K. C., and W. C. Martin, Jr. 1977. Effect of dikegulac as a post-shearing shoot-inducing agent on azaleas, Rhododendron spp. HortScience 12(4)9&337-338. 15. _ 1977. Research reveals qualities of a new chemical pinching agent for ornamentals. Am Nurseryman. October 15. 65-68. p. 11, Publications: 1. Shu, L. J. and K. C. Sanderson. 1980. Effect of dikegulac sodium on shoot growth of greenhouse azaleas. HortScience (in press). 27 California Nurseries: Innovations, Management and Problems Kenneth C. Sanderson Nature of Work: During the summer of 1977, the author traveled over 10,000 miles in California while on sabbactical leave from Auburn University. Observations were made at nearly 75 ornamental establishments, 20 botanical gardens, and 6 universities. Among the nurseries visited were C and M, Nipomo; Dahstrom and Watt, Smith River; Fern Mesa, Santa Maria; Lewis Gardens, Vista; Monrovia, Azuza; Nakona and Sons, Redwood City; Oki, Sacramento; Olive Hill, Fallbrook; Rogers Gardens, Newport Beach; Sunnyside, Watsonville; and Tropico, Gardena. Results and Discussion: California nurseries featured innovations in manageZone ment, greenhouse heating, media, salesmanship, and disease control. control management, television- and watch dog- security, tissue culture laboratories, and attractively landscaped premises were observed. One garden center is so attractive that they charge admission to the center on weekends. One nursery is grinding up styrofoam plastic packing material for use in potting media. Major problems confronting the industry involve labor, water, and energy. Unionization efforts and Occupational Safety and Health Act regulations are a major concern. Poor water quality has necessitated the use of reverseits osmosis and deionization. Energy problems related to greenhouse heating have been met by the installation of dual heating systems (oil-gas), foam insulated greenhouses and solar heating. Foot and vehicle baths of copper sulfate, copper napthalene spraying of wooden growing benches, diseases. Publications: None and aerated steam are used to control 28 A New Chemical Pinching Agent for Ornamentals Kenneth C. Sanderson Nature of Work: A new chemical pinching agent may replace shearing of pruning Tests in Europe (1,6) and the US (2,4,5) on many woody ornamental plants. have shown that Atrinal successfully pinches and shapes plants and increases the number of shoots without destroying plant tissue. The chemical has been a wide range of reported to cause branching, growth retardation or both in plants including cereals, cultivated and weed grasses, herbaceous and perennial plants and woody ornamentals. Chemically, Atrinal is the sodium salt of 2,3:4, 6-Bis-0-(l-methylethylidene)a-L-xylo-2 hexulofuranosonic acid and has the common name of dikegulac. Supplied as a foliar spray, Atrinal is taken up through the leaves and translocated the plant to the meristematic zones of growth. Auburn's initial experiment was conducted on small, young plants of rhododendron cultivar Kingfisher growing in a greenhouse in January. Azalea growers have reported that fatty acid pinching agents (Off-Shoot-0 throughout and Emgard 2046) produce more shoots and develop the best plant formation in combination with mechanical shearing (7). A second greenhouse experiment was Plants of the initiated in July to test Atrinal in combination with shearing. cultivars Alaska, Gloria and Red Ruffles (10 x 10 inches in size) were sheared one week before spraying at the rate of 18.3 milliliters per plant. Atrinal treat- ments were applied to the plants at concentrations of 3,000 to 6,000 parts per million using a low-pressure high-volume sprayer. included. A 42,000 ppm Off-Shoot-0 spray was also A randomized complete block design with five replications and three plants per treatment was used for each cultivar. On November 18, all plants were placed in a refrigerator at 450 under a continuous light intensity of 10 footcandles at the plant's top. The plants were moved to a greenhouse during January 9 to 30, 1976, and flowered using standard commercial 29 practices. Early workers (1) found Atrinal inhibited apical dominance and retarded growth in Ligustrum vulgare, Thuja occidentalis and Rhododendron simsi. Hield and Debie (2) have used Atrinal to retard vegetative growth of landscape plantings of Xylosma congestum, Pyracantha coccinca, Callistemon citrinus. Cotoneaster pannosus, Nerium oleander, Eucalyptus globulus, Fraxinus uhdei and Ulmus parvifolia. These workers reported long-term inhibition and simultaneous axillary bud growth on these plants. Phytotoxicity was observed with high treatment rates on Nerium and Eucalpytus plants. Auburn's research has considered Atrinal as a pinching agent in Ilex cornuta 'Dwarf Burfordi', Pieris phillyreifolia, Rhododendron prunifolium and Terstroemia gymnanthera. Liners in four-inch pots were sprayed with concentrations of 2,000 to 6,000 ppm in a greenhouse experiment conducted from June to December. Research and Discussion: Experiment 1 - Unsheared Azlaeas A week to 10 days after spraying with Atrinal, the immature leaves at the top of the plant turned yellow or chlorotic for seven to fourteen days, mature foliage was unaffected. however Shoot data were recorded in April, and Atrinal increased shoot number af follows: Treatment No. of shoots per plant 42 65 42 48 50 52 None Sheared 1,000 ppm Atrinal 2,000 ppm Atrinal 3,000 ppm Atrinal 4,000 ppm Atrinal 30 Experiment 2 - Sheared Azaleas Four to six weeks after treatment, shoot and leaf inhibition was most pronounced on all Atrinal. Growth appeared normal, but compact, approximately three months after treatment. The growth retardation associated with Atrinal treat- ment will make the timing of applications critical in order to faciliate shoot development and flower bud initiation. Spraying two weeks earlier than normal for hand pinching is allow complete bud development. suggested to The application of long days, growth stimulants or both to stimulate shoot elongation after pinching and lateral branch initiation warrants investigation. Sprays of 4,000 to 5,000 ppm Atrinal produced more shoots in Gloria and Red Ruffles plants whereas Alaska plants responded best to concentrations of 5,000 to 6,000 ppm as shown here. Treatment Shoots per plant cultivars Alaska None 3,000 Atrinal 4,000 Atrinal 5,000 Atrinal 6,000 Atrinal 42,000 ppm Off-Shoot-0 102 129 126 136 136 108 Gloria 110 140 167 172 162 135 Red Ruffles 65 97 117 117 107 82 31 Flowering time did not vary more than three days in any treatment. Due to compacted growth, Atrinal-treated plants appeared very floriferous, however 'Alaska and 'Gloria' plants did ndidnodiffer statistically in the total number of flowers. 'Red Ruffles' plants treated with 5,000 Atrinal had more flowers than untreated plants as follows: Treatment Flowers per plant cultivar· Alaska None 3,000 ppm Atrinal 4,000 ppm Atrinal 5,000 ppm Atrinal. 6,000 ppm Atrinal 42,000 ppm Off-Shoot-0 220 221 241 236 243 210 Gloria 204 246 230 229 225 233 Red Ruffles 102 102 127 140 132 112 Atrinal treatments had a profound effect on bypass shoots. The highest number of bypass shoots was observed on 'Red Ruffles' plants treated with Off-Shoot-0. Flower abortion was noted in two out of 15 plants receiving Off-Shoot-0. shoots in 'Gloria' plants were reduced by all concentrations of Atrinal. Treament Bypass shoots per plant cultivar Alaska None 3,000 ppm Atrinal 4,000 ppm Atrinal 5,000 ppm Atrinal 6,000 ppm Atrinal 42,000 ppm Off-Shoot-0 49 22 23 15 18 34 Gloria 33 14 14 8 8 27 Red Ruffles 57 57 37 39 40 65 Bypass 32 Auburn's investigations show that Atrinal treatments increase shoot number in azaleas. When used in combination with shearing, Atrinal increases shoot numA spray concentration of 5,000 ber, compacts growth and reduces bypass shoots. ppm was found to be effective on the cultivars tested. Experiment 3 - Woody Ornamentals Atrinal appeared to be a high effective pinching agent on Rhododendron prunifolium plants, but plants rapidly outgrew treatment effects. Ilex cornuta 'Dwarf Burford' plants did not exhibit the typical, temporary yellowing of immature foliage associated with Atrinal treatment. Excessive dosage rates, original growth condition of the plants and season of the year might explain the response of Ilex plants. Ilex growth was so poor that the plants were discarded after eight months (shoots were still too small to count at that time). Pieris phillyreifolia seemed to respond to Atrinal treatment, habit of growth made shoot counting impossible. but the vining Terstroemia plants sprayed with 4,000 ppm Atrinal had more shoots than sheared plants as shown by the following data: Treatment Sheared 2,000 ppm Atrinal 3,000 ppm Atrinal 4,000 ppm Atrinal 5,000 ppm Atrinal Conclusions Research shows that Atrinal is agent. Results indicate that it a safe and effective chemical pinching combination with Number shoots per plant 12 10 20 22 12 can be used alone or in shearing to increase shoot numbers and develop a better plant formation in azaleas. Initial test results show that Atrinal is also effective on certain woody ornamentals. 33 LITERATURE CITED 1. Bocion, P. F., W. H. DeSilva, G. A. Huppi, and W. Szkrybalo. 1975. Group of new chemicals with plant-growth regulator. Nature 258:142-144. 2. Sachs, R. M., H. Hield, and J. DeBie. 1976. Dikegulac: A promising new foliar-applied growth regulator for woody species. HortScience 10(4):367368. 3. Sanderson, K. C. and W. C. Martin, Jr. 1976. An evaluation of four new chemical pinching agents on azaleas. Res. Results Orn. Hort. Florist Crops. Auburn Univ. Ala. Agr. Exp. Sta. Hort. Series 24:7-8. 4. Sanderson, K. C., and W. C. Martin, Jr. 1976. New chemical pinching agent shows promise for controlling growth of woody ornamentals. Highlights Agr. Res. Auburn Univ. Ala. Agr. Exp. 5. Sta. Hort. Series 24:7-8. Sanderson, K. C. and W. C. Martin, Jr. 1977. Effect of dikegulac as a postshearing inducing agent on azaleas, Rhododendron cv. HortScience. 6. DeSilva, W. H., P. F. Bocion, and H. R. Walther. 1976. azalea with dikegulac. HortScience. 11(6):569-570. Chemical pinching of 7. Stuart, N. W. 1975. Chemical control of growth and flowering Chap. 8, pp. 62-72. in Growing Azaleas Commercially. A. M. Kofranek and R. A. Larson, eds. Univ. Calif. Sale Pub. 4050. 108 p. Publications: 1. Sanderson, K. C. 1977. Oct. 15. Research reveals qualities of a new chemical pinching agent for ornamentals. Am. Nurseryman. October p. 11, 65-68. 34 A Sabbatical View of Instruction at the Largest Ornamental Horticulture School in the United States Kenneth C. Sanderson Nature of Work: During 1976-77 Auburn University granted the author a 9-month leave of absence to teach at California Polytechnic State University (Cal Poly) plus a 3-month sabbatical leave to study California's ornamental industry. While on the staff of the Ornamental Horticulture Department at Cal Poly, the author taught floriculture courses, advised students, was a member of Ornamental Horticulture Club, and served on departmental committees concerned with the operation of the greenhouses and limiting student enrollment. During my studies in the industry, many products of Cal Poly's teaching program were also observed in managerial positions throughout the state. Cal Poly is a part of the California State University and Colleges and is fully approved as a 4-year degree-granting institution by the Western Association of Schools and Colleges. The campus consists of over 5,000 acres (20, 234.3 m 2 ) and adjacent to San Luis Obispo, an urban community of 35,000 located on U.S. Highway 101, midway between San Francisco and Los Angeles and 12 miles from the coast of central California. quarter of 1977 exceeded 17,000. Results and Discussion: The Ornamental Horticulture program is quite different from that of a traditional land-grant university. Since the primary responsibility of the Enrollment figures for fall faculty is teaching, the staff is not involved in research or extension. Faculty have been selected for their academic and commercial experience. Instructors receive strong support in the classroom from the university administration, a renown afdio-visual department, and clerical staffs throughout the university. up personnel, The OH department furnished laboratory set-up and cleanInstruction is occupationally laboratory assistants and graders. 35 oriented with the objective being to prepare the graduate to enter commercial practice. A constant inter-play between general principles and practical The latest techniques and "know how" En- application characterizes instruction. are more important than academic history and theory in the classroom. rollment figures for the fall quarter 1977 were 767 students and 20 staff. More than 40 courses stress the production and marketing of nursery crops, cut flowers, pot plants and tropical foliage plants; landscape design and construction; turf management; floral design and marketing; and diseases and pests. Unique course offerings include Bonsai, Ikebaba and tissue culture. Some courses are designed to aid the student in passing federal and state examinations necessary for certain ornamental operations. areas of specialization: Courses cover 4 nursery production and management, floriculture A basic production and management, landscape technology and floral design. OH curriculum exists for all students. during their first 2 years. Students take many ornamental courses Cal Poly provides practical experience to its students in many ways including: 1) an Agricultural Enterprise program, 2) a senior thesis, 3) a special projects course, 4) laboratory exercises, 5) internship programs, and 6) public service projects sponsored by the OH club and the Department. The Agricultural Enterprise Program is the most distinctive feature of Cal Poly's OH Department and approaches the zenith of practical experience. This program provides students with production, management, and sales experience while permitting them to share in the profits from their efforts. The enterprise program is financed by a non-profit corporation, the California State Polytechnic University Foundation which performs many funding functions within the university. This foundation operates under a lease agreement made with the Trustees of the California State University and Colleges and approval of the State Department of Finance. All accounts are subject to audit by the State Department of Finance and other control agencies. 36 The practical experience provided a Cal Poly student is to that of a traditional land-grant university. in stark contrast While the latter stress It is theory, Cal Poly stresses modern commercial techniques and action. felt that a blend of the two systems is needed in teaching ornamental horticulture today. Recent criticisms of ornamental horticulture instruction by industry make it imperative that the land-grant institutuions initiate practical experience programs. The high priority on teaching and teaching methods at Cal Poly should also be considered in land-grant institutions that have historically placed major emphasis on research. Request for graduates and observations of their successful performance in the industry makes criticisms of Cal Poly's program difficult. Nonetheless, it is apparent in the classroom Evi- that some Cal Poly students wish to be challenged in a different way. dence of the need for some basic theory is that Cal Poly is in our most highly respected ornamental graduate schools. placing students Also, it has been observed that some training on basic theory would facilitate the solution of production problems encountered by graduates in the industry. Publications: 1. Sanderson, K. C. 1977. Learning by doing - another approach, a sabbactical view of instruction at the largest ornamental horticulture school in the United States. 2. Proc. Fla. State iHort. 1978. Soc. 90:99-101. Sanderson, K. C. Rev. Providing experience - a teaching dilemma. Florists' February. a" "o