potted crops

Potting Ornamental Ginger With flowering potted increasing in popularity, ornamental ginger offers all the right qualities to achieve market success: it has bright, long-lasting flowers Clockwise from top: gracillima, Curcuma and it’s fairly easy to grow. alismatifolia, and Curcuma cordata. Below, right: The tuberous rhizomes characteristic of By Jeff Kuehny genus Curcuma and Globba. All photos courtesy of Jeff Kuehny. rnamental ginger, primarily from the depending on the climate. The most common Gingers grown for family, is a diverse genera used for these purposes include: flowering pot plants Oand versatile group of plants that are Curcuma, Globba and Kaempferia. (see Table 1) will flower gaining increased recognition in the flowering Most ginger are herbaceous perennials with more quickly and uni- pot , landscaping and cut flower markets. aromatic, short, thickened or long, thin rhi- formly if grown from The various sizes, flower colors and postpro- zomes. Some of these ginger rhizomes, such as rhizomes. If tissue cul- duction longevity (up to 4 weeks or longer) of those in the genus Curcuma and Globba, have tured plants are pur- these tropical and subtropical plants are adding tuberous storage vessels, attached by a modi- chased, a fuller plant a needed diversity to the greenhouse industry. fied underground stem, that have been termed can be grown by allow- Characteristics that make potted ornamental “t-roots” or “milk sacs.” A majority of these ing plants to go dormant in the fall. This is accom- ginger attractive to the floriculture industry are gingers are grown in Thailand, where rhizomes plished by withholding water as the days grow ease of production, unique foliage, numerous are harvested from December to April and shorter and temperatures become cooler. Many flowering stems per pot, long-lasting colorful shipped for forcing. Gingers can also be pur- growers then remove the dead foliage and force bracts, a 90 to 100 day production cycle and few chased in plug trays from tissue culture compa- the ginger rhizomes in the same container the disease or insect problems. Besides potted plant nies. However, if a finished plant is desired in a next spring, some time after February. use, they can be marketed for use in year round 60 day time period, the Kaempferia spp. is the interior landscapes and as either perennials or only ginger recommended for growing from a CULTIVATION INFORMATION summer annuals in exterior landscapes, tissue cultured plug. Once ginger rhizomes are received, they should be unpacked and inspected for damage Table 1. Ginger species recommended for pot production. or disease, as one would any other bulbous Species Average Height Inflorescence/Foliage T crop. Rhizomes should be planted immediately Cornukaempferia 1 foot Leaves w/ silver feathered margins to dark maroon after shipment; however, if they must be stored aurantiflora centers, small orange flowers Curcuma alismatifolia 2 feet shaped flowers, ~ 3 - 4”, pink or for a short period, they should be kept in a cool, white dry dark location. The longer the rhizomes are Curcuma cordata 2 - 3 feet Cone shaped flowers, ~ 4 - 5”, pink stored, the less time it takes for emergence. Curcuma roscoeana 2 - 3 feet Cone shaped flowers, ~ 4 - 5”, bright orange As with most bulbous crops, the media should Curcuma spp. 1 foot Tulip shaped flowers, ~ 1 - 2”, pink, pink w/green have excellent drainage and water holding tips capacity. We prefer a media that has a 3/6 peat, Curcuma spp. ‘Emperor’ Grown for variagated foliage and smaller tulip-shaped white flowers 2/6 pine bark, 1/6 perlite with a starter fertilizer Curcuma thorellii 1 foot Tulip shaped flowers, ~ 2 - 3”, pure white incorporated. The soil of the native habitat of ‘Chaing Mai Snow’ these gingers has a neutral to basic pH so Globba spp. 2 feet Arching pendulate flower stalks with white, pink, dolomitic limestone should be added to the dark purple or yellow bracts medium to provide a pH of 7 to 7.5. Kaempferia spp. Grown primarily for foliage K. gangla lay flat Foliage plain green with some varigation, small white A “standard” container or deeper pot will flowers provide for the best drainage and also provide K. gilbertii ‘3-D’ 6 inches Foliage with white margin, deep green room for placing the tuberous roots attached to stripes in center of leaves, small white flowers the rhizome toward the bottom of the pot, K. sp. ‘Grande’ 2 - 3 foot Foliage rounded and large with pattern upper while covering the top of the rhizome with and maroon underside approximately one inch of media. K. pulchra Breaking the tuberous roots from the rhizome

30 GPN February 2001 potted crops

may decrease flowering and delay grown under shaded conditions, white margin on a deep green leaf. time to emergence. Thus, care the flower stems and petioles tend Cornukaempferia aurantiflora has a should be taken to keep the entire to elongate and topple. The bracts silver feather pattern on the outer tuberous root intact. of the inflorescence tend to fade edge of the leaf with a deep A two-year-old rhizome plant- and postproduction longevity is maroon underside. Most of the ed in a 6-inch pot will produce a shortened. Curcuma alismatifolia and Kaempferia species produce small marketable finished plant. Some C. thorellii will produce a flower white, pink or orange flowers and companies do grade the rhizomes. approximately 60 days after emer- bloom sporadically throughout The grading system is usually gence and every 30 days thereafter the growing season. These gingers based on the number of tuberous during the summer months. grow best under 30 percent shade roots per rhizome. Curcuma cordata and C. roscoeana or greater. After the initial irrigation, plants will produce two to four large flow- As both day length (less than 12 should be given a preventative ers during the growing season. hours) and temperatures decrease, fungicide treatment. Most all Globba species and flowering will cease and the plants Greenhouse temperatures Curcuma gracillima grow best and will go dormant. As mentioned ear- should be kept at 85 to 90° F until flower under 30 percent shade. lier, these plants can be stored dry emergence of shoots. This will help Globba species, commonly called during the winter and forced again provide for a more uniform emer- “Dancing Ladies,” produce flow- sometime after February. gence. After emergence, green- ers at the end of emerging shoots house temperatures should be low- and will continue to do so during ered to less than 85° F. Some the growing season. Gingers of the gingers are boron accumulators, genus Globba have reflexed bracts which may lead to marginal necro- that are white to purple with a Dr. Kuehny at Lousiana State sis. Therefore, plants should be fer- slender, curved, yellow corolla. University and Dr. Criley at the tilized with a water-soluble fertiliz- Curcuma gracillima produce a sin- University of Hawaii are conducting er low in boron or without boron, gle inflorescence emerging from studies to provide production proto- such as a tropical foliage fertilizer. the rhizome, and it may be several cols for enhancing the production of months before another emerges. many of the gingers described in this POTTED GINGER The Kaempferia species are article. SPECIES grown primarily for their beauti- For production of brightly col- ful foliage (Table 1). Most ored bracts and deep green leaves, Kaempferia have a silver feather the “Surprise Ginger” including pattern in the middle of the upper The author would like to thank the Fred C. Top and middle: Commonly called “Dancing Ladies,” species of the Globba Curcuma alismatifolia, Curcuma cor- side of the leaf, radiating out- Gloeckner Foundation and the American genus produce flowers at the end of data, Curcuma roscoeana and wards with various shades of Floral Endowment for funding this study and emerging shoots. Bottom: Curcuma Curcuma thorellii should be grown green. While others, such as Mauricio Sarmiento and Patricia C. Branch roscoeana will produce 2–4 flowers in full sun. If these species are Kaempferia gilbertii ‘3D’, have a for their assistance in conducting the research. during the growing season.

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32 GPN February 2001