RAULSTON ET AL.: CULTURAL CONCEPTS 423

CULTURAL CONCEPTSOF L. PRODUCTION IN FLORIDA

J. C. RAULSTON, S. L. POE servation of the industry, review of the literature available, and present research data. The informa I FAS, Agricultural Research and Education Center tion presented herein will be expanded and modified Bradenton as more is developed for this crop. and Propagation F. J. Marousky The perennial white type which comprises al USD A Agricultural Research & Education Center most 100% of the Florida production, Gypsophila Bradenton paniculata L., can be grown from seed (1, 2, 10, 22) but seedlings are variable in quality and Abstract. Procedures for successful culture of degree of flower doubleness (5, 8) and are gen gypsophila under subtropical climatic conditions erally unsatisfactory for commercial production. are described. Rooted shoot-tip cuttings or * Paniculata double white' and ' Double Snowflake' grafted are used for planting stock. Gyp are white double-flowered perennial varieties sophila roots are easily damaged by high soil which can be grown from seed (2). Gypsophila temperatures, anaerobic conditions in waterlogged seed germinates bestat 65-75 °F and seedlings soils, high soluble salt levels and herbicide resi emerge 10-18 days after planting. G. paniculata dues. Well-drained calcareous soils with loose tex flowers from seed in four to six months. ture and good aeration are most satisfactory for Grafted plants. Commercial production of fully commercial culture. Major insect and disease double white G. paniculata 'Bristol Fairy* was tra problems include leafminers, armyworms, red ditionally based almost entirely on use of grafted spidennites and crown gall. Gypsophila plants plants (17). A 'Bristol Fairy' vegetative scion are dug, top vegetative growth is removed and is grafted to a root of ordinary single G. panicu roots are stored between production seasons. lata. This graft produces a vigorous which Large losses of stockoften result from root desic yields well and is preferred by commercial pro cation, disease development and excess vegeta ducers. Increasing labor costs for such specialized tive growth during storage. Vegetative shoot techniques has reduced the supply of grafted plants growth in storage is affected by both moisture and it is now more difficult to find sources which content of packing media and temperature. Opti can supply quantities required for field plantings. mum storage conditions are35° F with roots Another difficulty in production of grafted plants packed in a dry media such as peat moss or wood is maintaining propagating stock free of bacterial shavings in containers lined with a moisture crown gall organism (Agrobacterium gypsophilae) barrier such as polyethylene film. (3, 4, 13, 16, 20, 21). Once in a stock, crown gall is very difficult to eradicate. In production of Gypsophila is the third largest cut flower crop grafted plants from root cuttings clean rootstocks in Florida with an estimated 100 acres currently are essential; thus raising considerably the cost in production with an annual value of approxi of production. mately one million dollars (18). No information Own-root plants. Vegetative stem tip cuttings is published on commercial culture of this crop in of 'Bristol Fairy' can be readily rooted (6) and Florida, with only a few reports of disease inci this technique is used for the majority of com dence and various botanical descriptions in print. mercial production. Vegetative cuttings should be Research on gypsophila began two years ago at the taken from stock plants before flower initiation Agricultural Research and Education Center at begins. Gypsophila cuttings resemble carnation Bradenton and information is being accumulated. cuttings (both plants are in the It is a very difficult crop to research because of family (1), and are handled in a similar manner. plant variability and the nature of flowering which Stock plant shoots that begin to elongate and be make meaningful yield records difficult to obtain. come thin (thus indicating flower initiation) The following information was assembled from ob- should not be used as cuttings for propagation. Lower leaves on cuttings are removedand the Floricfta Agricultural Experiment Stations Journal Series stem base is dipped in a rooting hormone. Propa- No. 4772, 424 FLORIDA STATE HORTICULTURAL SOCIETY, 1972

gation under intermittent mist works well but care ber and continue through March. There is normally must be taken to use a clean and well-drained much variability in time of flowering of individual media since cuttings are sensitive to excess water. plants. If older plants (roots) are planted in the Plants root satisfactorily in about 3 weeks. Plants early fall, some flowers can be expected in No may be sold to growers either as rooted cuttings in vember with major harvests in December through 21/4// pots or as one year old plants with mature January. In greenhouse experiments, lighting of large fleshy roots. When year old plants are sold, plants each night has resulted in earlier flowering the top vegetative growth is removed by the of plants (15) but the extra yields probably would grower and roots are trimmed for packaging. not warrant the additional costs of lighting. Sev Roots of 'Bristol Fairy' are considered by some eral plantings should be made at 5-7 week inter growers to be weaker and more disease susceptible vals until December in order to extend the flower than the G. paniculata rootstock used on grafted season until June. Gypsophila plants are fairly plants. Own-root plants are thought to yield some tolerant of frosts and can be field grown success what less than grafted plants but no data are fully in any chrysanthemum producing area. Plants available to substantiate this. By the same stand are as tolerant of frost as calendula or stock, but ard, one-year plants supposedly produce more less tolerant than snapdragon or pansy (9). flowers than rooted cuttings even though cuttings Insect control Gypsophila grown in open fields grow rapidly and make a good sized plant the is host to several destructive insects for which first year. Plants from cuttings require longer some control must be applied. Only the more com to flower than plants from year-old roots. mon and destructive are discussed here. Moths. Adult moths seek seclusion among plant Culture foliage and weeds during daylight but become active at night and often fly long distances to Planting. Plants are usually purchased from locate an appropriate host plant. Eggs are laid northern growers in late summer or early fall and usually on the host leaves or stem either singly first plantings are made during September or or in masses of a few to several hundred. These October. A critical part of gypsophila culture at eggs hatch within a few days and larvae begin this time of year is keeping the plant roots from to feed and cause severe damage. Moths that waterlogging in hot weather. A heavy rain and/or attack gypsophilla include loopers, armyworms and a poorly drained soil during hot weather can cutworms. cause the loss of an entire field of plants in an afternoon as roots rot quickly under these con Loopers. The cabbage looper, Trichoplusia ni ditions. For this reason many growers wait for (Htibner) and soybean looper Pseudoplusia in- planting until heavy summer rains are past and cludens Walk are the most persistent loopers found high temperatures moderate in the fall. This is on gypsophila. Larvae are slender bodied, pale the main limiting factor for early production and green with stripes and move in a looping or inch- is one reason little gypsophila appears on the worm manner. They hatch from eggs laid singly market before November and December. Good and their feeding results in partially consumed drainage is absolutely essential for this crop. Much ragged leaves with large holes. Loopers may be of the gypsophila in Florida is grown similar to controlled with any of the better formulations of gladiolus production in open field culture on un- Bacillus thuringensis (14). fumigated soils. Where possible, growers plant Armyworms and cutworms. Common pests in in new land each year to escape the buildup of cluded in this group are beet armyworm, Spodop- disease organisms which occur if gypsophila is tera exigua (Hubner), southern armyworm, S. grown repeatedly in the same location. Soil fumi eridania (Cramer), and granulate cutworm, Feltia gation with tarped methyl bromide or Vorlex is subterranea (Fab.). Damage by the armyworms is desirable and will allow repeated production in a similar to looper injury but more extensive. given soil. If the land is subject to flooding, the Larvae are gregarious and may consume an entire plants should be set on rather high beds to im plant or branch. Beet armyworms are pale to dark prove drainage. Plants are usually set about 2' - 3' green, southern armyworms brown with black apart and drainage ditches every 5-10 rows. This velvet appearing patterns. Early stages of the provides a plant population of about 3,500 to 5,000 former species behave as a webworm, spins a web plants per acre. tying the leaves together and feeds from within Harvest of flowers from September-October the enclosure. Cutworms spend the day near the plantings of cuttings will usually begin in Decem soil line but leave this shelter to forage at night. RAULSTON ET AL.: GYPSOPHILA CULTURAL CONCEPTS 425

They are large pale brown larvae that curl into quired. The major cause for alarm from this pest a C-shaped form when molested. Armyworms and is the presence of honey dew secreted by the aphids cutworms can be controlled with methomyl or onto the foliage which provides a medium for carbaryl (14). pathogen development. Plants appear to be covered Leafminer. These insects are larvae or maggots with a black soot-like mold which may affect photo of small flies with black and gold markings. The synthesis through light reduction and hence affect most common are species of Liriomyza. The adults yield. If treatment is required, aphids can be lay eggs in the leaf tissue by inserting a blade-like controlled with dimethoate, zectran or oxydemeton ovipositor. This puncture causes sap to flow from methyl (14). the wound and this sap forms a source of food for Saprophytic mites. Included here are the sev the adults. Single eggs hatch within a few days eral species of saprophytic mites found generally and the tiny maggot begins to tunnel within the on rotting, diseased bulbs, corms, tubers or rhi leaf leaving a white serpentine trail. Leaves may zomes. The growth of gypsophila from an under be heavily damaged by feeding tunnels and activity ground foodstorage organ often provides an ideal of these pests may lead to secondary infestions condition for mite infestation. Large populations from disease organisms. Mature maggots emerge may become prevalent when the soil is wet and the from the tunnel, drop to the soil and become in roots decay. These organisms feed on the rotten active puparia from which the adult fly emerges plants and pathogens but may mechanically spread within a few weeks. Azinphosmethyl, diazinon or unwanted disease-causing pathogens throughout zectran provide the best control measure (14). the soil. The best treatment for mite control is in Red Spicier, Spidermites. These tiny pests, about complete disease control and prevention of decaying l/50th" long, greenish, reddish or yellowish, are plants through improved drainage. not insects or spiders but mites. They cause damage by feeding with needle-like mouth parts which Nutrition and Weed Control. In addition to puncture individual plant cells and extract fluids. water damage, gypsophila roots are reportedly All stages—egg, larva, nymphs and adult are sensitive to herbicides (7) and high soluble salt present at the same time on the host. Under levels. Little research information is available optimum conditions a generation can be completed in either area but several growers have mentioned in 10-14 days. Each female lays singly many eggs herbicide injury. Weed control can be difficult over a 20-30 day period, hence, generations over as plants are in the field many months and sprawl lap. Between each stage of development is a period over an area 3' - 4' in diameter, making mechani of inactivity during which molting occurs. During cal cultivation around plants difficult. this period, treatment for control is less effective Moderate fertilizer schedules should be fol since the new skin is protected by the molted skin. lowed—somewhat similar to those used for gladio Consequently, treatments applied at three or lus, and considerably less than for chrysanthemum four day intervals result in better control of this culture. Superphosphate and fritted trace elements pest. Sprays and systemic materials can be used should be incorporated during soil preparation. (14). Nitrogen and potassium sources should be applied Thrips. Thrips most likely to be troublesome at planting and periodically (each 3-5 weeks) dur are the flower thrips, Frankliniella spp. Popula ing crop growth. Total amount and number of tions build up on many alternate host flowers applications will depend on soil types, rainfall (weeds, clover, citrus) during spring and migrate dui'ing the season, etc. Soluble salt readings of to fields of gypsophila where they infest the tiny the normal sandy soils of Florida flower areas blooms. Their rasping and shredding of tissues should be maintained roughly in the range of result in yellowing or browning of the flowers and 800-1200 ppm (1:2 soil:water by volume. See wilting or secondary disease development. Protec Waters et al (22) for details) with a pH of 6.5- tion should be given the plants during heavy 7.5. Gypsophila will tolerate higher pH ranges thrips flights by sprays of endosulfan or azini- than most flower crops as it is reported to grow phosmethyl. If aldicarb has been used for spider- best on dry, calcareous gravelly soils (2, 5, 20). mite control, additional treatments may be omitted. The name "gypsophila' literally means "gypsum- Aphids. Occasional pests of gysophila include loving," referring to the native habitats of the aphids, primarily the green peach aphid, Myzuz plant (1). Consequently gypsophila should per&icae (Sulzer). Large populations seldom de grow very well on the "rockland" soils of Dade velop, however, and treatment may not be re county, although no producers of gypsophila are 426 FLORIDA STATE HORTICULTURAL SOCIETY, 1972

located there at present and no trials have been about 40% is sold on an FOB shipping point basis. made. The FOB price to wholesalers ranges from $.70 - 1.00 a bunch for all three grades with most sales at Flower Harvest and Post-Harvest Handling $.90 - 1.00." Of course, individual growers vary consider This is one of the most critical and difficult ably in grading and shipping techniques used. aspects of successful gypsophila culture. Gpysophila Cooperative research by USD A and AREC- plants produce flowers in a large, panicle-like com Bradenton has shown gypsophila responds well to pound diachasium in which individual flowers do flower preservative solutions (11). Flowers will not open simultaneously. The is char keep and continue to grow and develop in a solu acterized by development of a single branch at tion of 200 ppm of 8-hydroxyquinoline citrate (8- each node giving an appearance of alternate HQC) and 2% sucrose (S). In water little fur branching. The tip or apex of the panicle opens ther development of flower opening occurs after first and must be harvested separately before the harvest and flowers may shrivel when in storage entire panicle is open. The flowers are sensitive or in arrangements. In 8-HQC + S gypsophila to water deficit and intense sunlight, and will flowers continue to open until every bud in the brown and shrivel easily if subjected to stress panicle is fully expanded, and will last up to 3-4 conditions. When flowers are overmature they are times as long as flowers held in water. Tests have not saleable;' therefore, harvesting requires a indicated that gypsophila can be harvested and well-trained employee with an experienced eye to bunched when panicles are in tight bud (when cut stems with flowers open—but not overmature. first flowers on a panicle begin to open). Bunches Plantings should be harvested frequently to obtain are then placed with stems in 8-HQC + S and the highest quality flowers. Hot, dry winds can the containers are placed in a holding area at 72- quickly produce stress conditions which desiccate 76°F for opening to the commercial stage. Flowers flowers and can destroy whole fields. Flowering handled this way open much better than normal stems are usually cut 10-14" long, graded into development in the field and the dangers of flower a 6-10 oz. bunch and the stem ends wrapped with browning, shriveling and disease losses which often a rubber band. A bunch may vary from 5-25 stems occur in the field are greatly reduced if not depending on quality and stage of the harvest at eliminated. any given time. Flowers are very susceptible to drying after harvesting and must be kept in water In another experiment, it appears that the under refrigeration to maintain quality. It is also rapid decomposition (and unpleasant odor) of cut advantageous to hold flowers in water during the stems in water due to water molds may be reduced shipping period, however, shipping containers or eliminated by adding sodium benzoate to the holding water is difficult and major airlines will holding solution without any deleterious effects on not accept flower packages which contain water. lasting life or quality of the flowers. The use of Gypsophila stems begin to decompose quickly 8-HQC -j- S and sodium benzoate are both pre- after being placed in water and can be very dis limitary observations but results indicate growers, agreeable to handle and are unpleasant smelling. retailers and consumers could greatly benefit by Flowers held in water at 40 °F will sustain evaluating these observations. shipping quality better than flowers held at 33 °F Dried Flowers. A good market exists for dried (11). Boxes lined with polyethylene film will re gypsophila flowers for use in both fresh and dried duce moisture loss but botrytis may be a problem flower arrangements by florists. In northern whole if flowers are not cooled before packing and sale flower markets dried gypsophila often brings moisture condenses on the flowers. The ornamental twice the price of fresh material; selling for $2.50 crop market report summary (18) gives the fol to $4.50 per bunch on the New York and Chicago lowing information: markets. Dried gypsophila is presently produced in "A 18" x 20" x 24" wire bound crate is used other areas of the U.S. An opportunity exists for for truck shipment. Some 20-30 bunches with Florida growers and could be exploited by enter stem ends immersed in a bucket of water are prising persons. Although usually dried in the packed in a crate. When sent by air, 60 bunches are bunch form, individual panicles can also be packed in a 11" x 18" x 48" carton without water. pressed and dried (19) for use in floral plaques, Grading is done according to stem length and for sealing in transparent or translucent plastic, marketed as small, medium and large. It is esti for screens, and for Victorian bouquets. Bunches mated that 60% is consigned to city markets while can be dried by hanging them upside down in a RAULSTON ET AL.: GYPSOPHILA CULTURAL CONCEPTS 427 relatively dry dark room. Rapid drying with a Packing in wet media to reduct drying losses will hot air "blast will cause excessive shriveling and result in severe disease losses in storage and if brittleness. Packaging and shipping are the major temperatures are above 40°F, excess sprouting will difficulties in merchandising this produce because also occur. Our research has indicated that lining dried flowers are brittle and break easily when storage containers with a moisture barrier of poly handled. ethylene film and packing roots in dry peat or wood shavings will reduce storage loss. Digging and Storage The polyethylene film should be overlapped or folded at top but not sealed tightly. It is im Although gypsophila plants are perennial in portant to use a material such as polyethylene temperate areas, roots must be dug and stored which allows gas exchange yet forms a moisture during the summer months in Florida as plants in barrier. Anaerobic conditions in the root areas the field are quite susceptible to disease losses will cause severe root damage. Storage at 32-35 °F during extreme heat and moisture conditions in is most desirable but if packed in a dry media, Florida during June, July and August. Plant losses roots can be held at 42-45 °F without excess sprout in storage have often been as high as 70%. Tops development. Sprouting occurs readily at 45 °F if of the plants should be cut back before digging, adequate moisture is present. Packed properly and leaving 2-4" of the stem above ground. When held at 32-35 °F, roots can easily be stored 8-12 plants are dug, the large fleshy roots usually need months. trimming for convenient storage. Normally, roots When planting in hot weather, boxes containing about 10" long are stored but various growers roots should be removed from cold storage several retain different amounts of the roots—varying days before planting and allowed to come to out from 6" to 18". On young plants which have not side air temperature. New stock (cuttings or developed the large fleshy 1-2" diameter roots, young roots) planted in the fall can normally be the entire root system can be stored. dug and stored the following two summers for a Trimming roots for storage is one time and total of 3 years of production. Uncontrolled crown place for rapid spread of crown gall bacteria (16). gall disease in stock can limit production to one or Every effort should be made to maintain sanitation two seasons. Stock can rarely be maintained in a to reduce losses at this point. Growers should healthy and vigorous state for four or more years; discard badly infected plants as they store poorly therefore, a grower should plan on replacing 25- and have low productivity the following season. 40% of his stock each year. Some growers feel It is probably impractical to discard all plants that with disease losses and costs of digging and showing any sign of crown gall as it is almost storage of roots, it may be most economical to universally present. If small lesions up to one inch purchase new stock each year. in diameter are present, the roots can be saved for one more season of production. Lesions larger than this generally weaken the plant too much Literature Cited for economic production. Cutting tools should be 1. Bailey, L. H. 1922. The Standard Cyclopedia of Horti culture. 6 Vol. disinfected between plants to reduce the disease 2. Ball, Vic. (Ed.) 1972. The Ball Red Book 12th Ed. 502 p. (see p. 345). Geo. J. Ball, Inc. spread. A 2-minute dip in calcium hypochlorite 3. Brown, N. A. 1932. Another gall-forming bacterium. solution has been reported effective in reducing Phytopath. 22 (11) : 924-925. 4. 1934. A gall similar to crown gall, spread of crown gall in grafting or trimming of produced on gypsophila by a new bacterium. J. Agr. Res. 48 (12): 1099-1112. gypsophila plants (13). 5. Darwent, A. L. and R. T. Coupland. 1966. Life history The two major causes of root storage loss are of Gypsophila paniculata. Weeds 14 (4): 313-318. 5. Dorsman, C. and K. Kavensberg. 1957. (Cuttings and desiccation of the roots or excess moisture in the grafts under mist spray.) (Dutch) Jaarb. Proefst. Boomkev. Doskoop 1957:20-31. packing media. If roots are piled loose in con 7. Ivens G. W. 1964. Experiments on weed control in tainers, or even packed in various media open to sown flower crops. Proc. 7th Brit. Weed Cont. Conf.-.248-255. 8. Jankalov, J. K. 1969. (Results of selection work with the air, desiccation will occur under conditions gypsophila.) (Bulg. with Engl. and Russ. summaries). Proc. Sci. Sess. Inst. Genet. Plant Breed. Sofia. 1967: 165-171. existing in most storage rooms and roots will 9. Kantartzis, N. A. 1964. (Frost resistance in annual die when a critical moisture level in the tissues is spring-flowering ornamental plants.) (Greek with Engl. Summar.) Geoponika 120/121:195-202. reached. Sometimes when containers are stacked 10. Lawrence, G. H. M. 1953. The cultivated species of Gypsophila. Baileya. only those in the outer layer will be affected. 11. Marousky, P. J. and J. Nanney. 1972. Influence of Satisfactory storage can be achieved without a storage temperatures, handling and floral preservatives on post harvest quality of gypsophila. Proc. Fla. State Hort. packing medium if roots are held in crates in Sci., (in press). 12. Pirone, P. P. 1945. Control of the gall disease of storage rooms maintained at a high humidity. Gypsophila caused by Phytomonas gypsophilae (Brown) Ma- 428 FLORIDA STATE HORTICULTURAL SOCIETY, 1972

gron. Phytopath. 35(5): 368-369. Summary 1972 season. Federal-State Market News Service. 13. , B. O. Dodge and H. W. Rickett. Orlando, Fla. 41 p. 1960. Diseases and pests of ornamental plants. 3rd Ed. 776 19. Squires, M. 1958. The Art of Drying Plants and p. (see p. 399). The Ronald Press Co. N. Y. Flowers. Gramercy Publishing Company. 258 p. 14. Poe, S. L. and D. E. Short. 1972. Control of major 20. Tucakov, J. 1958. (Medicinal and aromatic plants of anthropod pests on commercial flower crops. Fia. Coop. the Danube sands near Deliblato in Yugoslavia. Economic im Ext. Serv. Plant Protection Pointer No. 50. 10 p. portance and possibilities of cultivation.) (French) Qual. 15. Redington, G. 1929. The effect of the duration of light Plant. Mavey. S:108-120. upon the growth and development of the plant. Biol. Rev. =p 21. Verona. O. and N. Loprieno. 1956. (Root galls in Biol. Proc. Cambridge Phil. Soc. 4(2) : 180-208. Gypsophila paniculata L.) (Italian with Engl. Summ.) Ann. 16. Riker, A. J., E. Spoerl, and A. E. Gutsche. 1946. Sper. Agrar. 10:133-143. Some comparisons of bacterial plant galls and of their causal 22. Waters W. E., J. NeSmith, C. M. Geraldson and S. agents. Bot. Rev. 12 :57-82. S. Woltz. 1972. The interpretation of soluble salt tests and 17. Samson, R. 1950. Grafting Gypsophila Bristol Fairy. soil analysis by different procedures. Fla. Foliage Grower The Professional Gardener 2:31-32. 9(6):l-10. 18. Scarborough, E. F., K. G. Gholston and R. P. Calla- 23. Weber, W. A. 1955. Additions to the flora of Colorado. way. 1972. Marketing Florida ornamental crops. Part. 1. II. Univ. Colo. Stud. Ser. Biol. 3:65-108.