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CFREC-A Foliage Plant Research Note RH-91-35 L.S. Osborne, R.W. Henley and A.R. Chase
University of Florida, IFAS Central Florida Research and Education Center - Apopka 2807 Binion Rd., Apopka, FL 32703-8504
WAX PLANT (HOYA)
Wax plant belongs to the genus Hoya, a member of the milkweed family, Asclepiadaceae. Wax plants grown in the foliage plant industry are primarily cultivars of one species - Hoya carnosa. The preferred common name of the species is wax plant, but wax vine and porcelain flower are occasionally used. The fleshy leaves and flowers, which are covered with a semi-glossy layer of waxy substances known as the cuticle, account for the common names given to the group. A few other species, such as H. australis, H. bella and H. multiflora, are produced by a few nurserymen.
The wax plant is a semi-woody vine with nearly oval or ovate-shaped leaves 2 to 3 inches long arranged oppositely along the stems. The flowers develop in clusters 2 to 3-1/2 inches in diameter. The individual flowers (florets) are attractive and consist of five white to pink symmetrical outer lobes, about 5/8-inch across, and an inner structure which is red or partly red. The inflorescences develop from the ends of short spur-like branches along the vines. These spurs increase in length slowly with each successive cycle of bloom.
Wax plant is a minor foliage crop, constituting less than one percent of the total foliage plant product mix grown in Florida. Although the plant is well adapted to interiors with 125 foot-candles or more of light for approximately 10 hours per day, it is not a favorite of many growers because of its lengthy production schedule. It is most commonly grown in 3-inch square pots, but a few producers offer it in 4-inch and larger pots. The plant is most attractive when finished in hanging baskets which display the trailing habit of the vines and the attractive flowers which appear periodically on older plants. Occasionally wax plants are cultured as totems, a form which is usually not cost effective for the commercial producers because of the lengthy growing period and labor required to train the vines on a pole or slab.
There are several cultivars of Hoya carnosa which are
grown by commercial growers in Florida. Those cultivars of wax
plant which have been cultivated with some frequency are as
Horticultural name Common name - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Hoya carnosa Wax plant Hoya carnosa `Argentea Picta' (pat. 3307) Hindu rope (R) Hoya carnosa `Compacta' Hoya carnosa `Mauna Loa' (pat. 3054) Lura-Lei (R) Hoya carnosa `Compacta Regalis' (pat. 3306) Hoya carnosa `Krinkle 8' (pat. 3008) Krinkle 8 (R) Hoya carnosa `Krinkle 8 Variegata' Variegated Krinkle 8 Hoya carnosa `Rubra' (pat. 3105) Krimson Princess (R) Hoya carnosa `Tricolor' (pat. 2950) Hoya carnosa `Variegata' Variegated wax plant Hoya purpurea-fusca `Silver Pink' Silver pink wax plant
Wax plant is propagated from cuttings which are harvested from stock vines. Normally single-node cuttings are made with a cut approximately 1/4 inch above each pair of leaves, leaving a longer stem section below the leaves to anchor cuttings which are usually direct stuck. Cuttings root in 3 to 4 weeks and a single shoot usually develops from one of the buds on each cutting approximately 4 to 6 weeks later. Roots form along the stem section below soil level with the greatest number of roots developing at or near the node (point where leaves are attached to the stem). Cuttings should be positioned so the node is at the soil surface to ensure maximum rooting. Avoid sticking cuttings too deep as shoot development will be inhibited or prevented if buds are positioned below the soil surface.
Wax plants develop best under light intensities of 1500-2000 foot-candles and temperatures of 68 to 75°F. Summer rooting and growth of wax plant can be reduced if temperatures are excessively high due to poor ventilation or inadequate cooling. If greenhouses are run very cool in winter, plants will become dormant. An acceptable production temperature range is 68 to 90°F.
After cutting material is harvested from stock plants, water management becomes one of the most critical factors in propagation. As long as greenhouse relative humidity is high (75 percent or more), the unrooted cuttings should not be misted frequently. Simply apply enough water overhead to keep the soil surface moist, not soggy. After roots develop to the bottom of the pots, the watering frequency should be reduced to permit the potting medium to become relatively dry before the next irrigation.
Most wax plant growers prefer liquid fertilizer application over incorporated slow release products so the fertility level of the potting medium can be adjusted easily as the crop irrigation frequency is changed. Fertilizers with a 2:1:2 or 3:1:2 ratio with microelements added are a good choice. Apply fertilizer at the rate of 2.9 pounds of actual nitrogen per 1000 square feet per month.
Potting media should contain a high percentage of organic material, such as fibrous peat, to provide good water holding capacity and some coarser particles, such as pine bark, perlite and calcined clay to assure good drainage and aeration. Several of the commercially available preblended soilless mixes are suitable for growth of high quality wax plants.
Production schedules vary considerably depending upon cultivar, temperature and degree of water management. The flat-leaf, all-green types grow more than twice as fast as plants with variegated, reflexed leaves and short internodes. It takes approximately 5 to 11 months to produce a finished 3-inch pot of wax plant with a 6 to 8-inch long vine from an unrooted, single- node cutting. One or two cuttings are stuck per 3-inch pot and 3 to 4 single-node cuttings stuck per 4-inch pot.
Reference Pest Control Guides Here
1) Botrytis blight (Botrytis cinerea)
2) Stem and root rot (Phytophthora, Pythium and Rhizoctonia spp.)
INSECT AND RELATED PROBLEMS
Reference Pest Control Guides Here
The major arthropod pests of this plant species include aphids, moths (worms), fungus gnats, mealybugs, mites, scales, and thrips. Mealybug, mite, and scale infestations are typically the result of bringing infested plant material into the greenhouse. Aphids, moths, fungus gnats and thrips have the ability to fly and thus invade the greenhouse from weeds and other infested plants outside. In the control section for each pest, a few of the many registered and effective pesticides will be listed. For a complete listing please consult the references at the end of this report.
2) Fungus gnats
4) Mites (Broad mite)
6) Shore flies
Reference Pest Control Guides Here
Pesticides should be applied according to label
Regardless of the pesticide or mixture
of pesticides used, it is
strongly recommended that the effects be evaluated on a few
plants, under your particular conditions before treating all plants.
Mention of a commercial or proprietary
product in this paper
does not constitute a recommendation by the authors,
nor does it imply registration under FIFRA as amended.
1. Anonymous. 1984-1985 Florida Foliage Locator. Florida Foliage Association. 160 pp.
2. Bailey, L.H. Hortorum staff. 1976. Hortus Third. MacMillan Publishing Company, Inc., New York, NY. 1290 pp.
3. Chase, A.R. 1983. Phytotoxicity of some bactericides and fungicides on some ornamentals. Nursery Digest 24(5):11.
4. Conover, C.A. and R.T. Poole. 1990. Light and fertilizer recommendations for production of potted foliage plants. CFREC-A Research Report RH-90-1. 13 pp.
5. Price, J., D.E. Short and L. S. Osborne. 1989. Management of fungus gnats in greenhouse ornamentals. Extension Entomology Report #74.
6. Short, D.E., L.S. Osborne and R.W. Henley. 1984. Phytotoxicity of insecticides and miticides to foliage and woody ornamental plants. Extension Entomology Report #57. 32 pp.
7. Short, D.E., L.S. Osborne and R.W. Henley. 1991. 1991-92 Insect and related arthropod management guide for commercial foliage plants in Florida. Extension Entomology Report #52. 13 pp.
8. Simone, G.W. and A.R. Chase. 1989. Disease control pesticides for foliage production (Revision 4). Plant Pathology Extension PPP#30. Plant Protection Pointer 30. 54 pp.