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Publication #ENH861

Japanese Pittosporum/Tobira Production and Use1

Robert H. Stamps2

Figure 1. 

There are several green and variegated forms of Japanese pittosporum.


Credit: Robert H. Stamps
[Click thumbnail to enlarge.]

FAMILY: Pittosporaceae

GENUS: Pittosporum

SPECIFIC EPITHET: tobira

CULTIVARS: 'Compacta', 'Glen St. Mary', 'Louisiana Greek', 'Nana', 'Variegata', 'Wheeler's Dwarf', 'Laura Lee' (PP#5893)

Pittosporum tobira (Thunb.) Ait., Japanese pittosporum, is a popular evergreen shrub that is used as a landscape plant, as a cut foliage crop, and occasionally as a potted plant for interiorscapes. In 1983, the last year for which a published estimate is available, Japanese pittosporum accounted for about 5% of the U.S. cut foliage market. Variegated pittosporum (cv. Variegata) is the most popular cultivar and brings a higher price than the green.

Floral Design, Landscape and Interiorscape Use

Floral Design Use

P. tobira stems are used as filler material in floral arrangements; in addition, the rosettes of leaves are used singly and in groups as mass materials. Pittosporum is usually used fresh and is available year-round; however, supplies may be short during the spring when the new foliage flushes and is not harvestable because it is immature, soft and likely to wilt. The dwarf varieties ('Compacta', 'Laura Lee', 'Nana', 'Wheeler's Dwarf') are rarely available from commercial sources due to their slow growth rates. In addition to fresh foliage, dried fruit of pittosporum is suitable for use in floral arrangements.

Landscape Use

P. tobira is a shrub that withstands trimming well and is used for foundation, hedge and mass plantings, as a screen, and in planter boxes. Most insect and mite problems listed below are not generally a problem in the landscape but can occur during intensive commercial production, especially if pesticides are not used wisely. Aphids, cottony cushion scale (Icerya purchasi) and Cercospora leaf-spot can be problems on this landscape plant. Pittosporum are also known for their susceptibility to root-knot nematodes (Meloidogyne spp.).

Interiorscape Use

Acclimatized P. tobira potted plants have been shown to hold up well under interior conditions with the green form performing better than the variegated form. However, neither form is widely used in interiorscapes because of the availability of many other more exotic or tropical-looking plants.

General Cultural Requirements

Temperature:

AHS Plant Heat Zones: 12–3

USDA Plant Hardiness Zones: 8–10

P. tobira is a subtropical plant that can be cold damaged in Florida during winters when temperatures dip into the low 20s or colder, especially if cool weather has not preceded the freezing event(s) and the plants have not become cold acclimated. Some producers freeze-protect pittosporum with water, but using water can lead to ice buildup and broken limbs. If the water supply is interrupted for any reason or if not enough water is applied, cold damage can be more severe than if water was not used.

Soil: P. tobira is not particularly sensitive to soil pH, but it is suggested that the pH should be slightly acidic. Fertile and well-drained soils are preferred, especially to reduce the incidence of Pythium root rot (see Main diseases section below).

Fertilization: Research suggests that fertilization rate has little effect on cut foliage yield of pittosporum; in fact, neither green nor variegated pittosporum yields were affected by fertilization rate when they were grown on Tavares-Millhopper fine sand soils fertilized with a 6-6-6 [6N-2.6P-5K] fertilizer at nitrogen application rates ranging from 143 to 571 lbs/acre/year [160–640 kg•ha–1yr–1]. The lowest fertilizer application rate produced higher yields than the other rates for both green and variegated pittosporum. This is particularly interesting since the soil used in this research, Tavares-Millhopper fine sand, has a poor cropland capability classification of IIIs—droughty, severely limiting crop selection. Fertilization should be based on soil tests, and fertilization intervals should be based on nutrient release rates from the fertilizer materials.

Light: P. tobira can be grown in full sun to partial shade; however, research has shown that growth of potted pittosporum is higher under 47–80% shade than under full sun or 30% shade. It is not recommended that shade-grown potted pittosporums be planted under full-sun conditions because the sun would burn the shade-produced leaves.

For cut foliage use, yields are generally higher under 47–55% shade than under lower or higher shade level. Foliage produced with 47% shade may be inferior to that produced under heavier shade. Foliage produced under less than 47% shade (higher light) levels is usually unacceptable to florists because of washed-out coloration and upright rather than flattened orientation of the leaves. In one study, stems produced under 70% shade lasted slightly longer (38 days) than stems produced under 50% shade (34 days), a difference of little commercial significance.

Water: P. tobira are somewhat drought tolerant, but for commercial production the growing media should be kept moderately moist. Irrigation systems should apply water evenly, especially if those systems are used to apply fertilizer and/or pesticides. This pittosporum has good salt tolerance.

Planting: Potted pittosporum can be transplanted into the landscape any time of the year. For landscape uses, plant spacings of three feet [0.9 meter] are recommended for foundation plantings and of 1½ feet–three feet [0.46–0.9 meter] for hedges and screens. For cut foliage production, pots of three-gallon [11-L] size are most often used when establishing plantings. Optimum plant spacing depends mostly on how large the plants will be allowed to grow in size and how much they will be cut back at each harvest. Pittosporum are sometimes planted too close together initially—making it hard for cutters and pesticide applicators to get through the field when the plants reach harvestable size. A spacing of four feet × six feet [1.2 meter × 1.8 meter] has worked well for many growers.

Propagation: P. tobira is most commonly propagated using cuttings. Semi-hardwood cuttings will root readily under mist, especially if the basal ends of the cuttings are treated with indolebutyric acid (IBA) at concentrations from 1,000 to 3,000 ppm [1–3 g•L–1 or g•kg–1]. Research indicates that cuttings survive and root best in freely draining/well-aerated propagation media such as polyurethane and polyphenolic foam rooting cubes or mixtures of perlite and peat (50% each by volume). Seed germination may be hastened by treating the seeds for several seconds with boiling water.

Common Cultural Problems

Main pests: Japanese pittosporum is a host to numerous insects and mites, but neither need be serious problems if the crop is managed properly.

Insects - [Note: for specific insect control recommendations go to http://edis.ifas.ufl.edu/IG012.]

Aphids are the main pests and are easy to control, but improper use of pesticides to control aphids can lead to subsequent severe outbreaks of mite infestations (see mite section below).

Figure 2. 

Leafhoppers (red and blue insect on right) and aphids are common pests on immature foliage of P. tobira.


Credit: Robert H. Stamps
[Click thumbnail to enlarge.]

Symptoms - Small, succulent-bodied insects found attached mainly to the undersides of immature foliage and around young stems. New foliage is reduced in size, curled backwards and often distorted.

Control - In order to reduce detrimental impacts on beneficial insects and mites, use systemic materials taken up by the roots of the plants and short-lived foliarly-applied insecticides.

Leafhoppers, like aphids, have piercing-sucking mouthparts and feed by sucking plant sap from vascular plants.

Symptoms - Small (usually no longer than about ¼ inch [6 mm]), wedge-shaped, and capable of hopping away rapidly in all directions when disturbed. The head from above is broadly curved or triangular and the wings are held rooflike at rest. Some are brightly colored (see Figure 2). Like aphids, they are often found feeding on the undersides of foliage.

Control - Similar to that for aphids.

Scale, especially cottony cushion scale, can become a problem over time and should be scouted for regularly.

Figure 3. 

Cottony cushion scale (Icerya purchasi) is a common insect pest on pittosporum.


Credit: Robert H. Stamps
[Click thumbnail to enlarge.]

Symptoms - The large, white, cottony, fluted egg sac attached to females is the most commonly seen symptom of cottony cushion scale. Egg sacs contain hundreds of red eggs that hatch into bright red nymphs (immature instars, commonly called scale crawlers) that at first feed on leaves and then later on twigs and branches.

Control - Chemical control can be somewhat difficult due to the cottony wax coating covering the later stages of development of this insect. Systemic insecticides and insecticides that coat and suffocate all developmental stages (e.g., oils) offer the best control.

Mites - Several species of mites can be a problem on pittosporum, especially if beneficial mite parasites and predators are killed by using broad-spectrum insecticide/miticides in attempts to control aphids or mites.

Figure 4. 

Severe mite infestations result in a speckled leaf appearance. Regular scouting should be conducted to monitor for mites, and treatments should be made before this level of damage occurs.


Credit: Robert H. Stamps
[Click thumbnail to enlarge.]

Symptoms - Minute eight-legged creatures found on undersides of leaves or found running across a light surface after the foliage is beaten against the surface; silk webbing on the undersides of leaves; silvery-stippled appearance of leaves (see above).

Control - Both biological and chemical mite control agents are available. Information on biological control of mites is available at http://mrec.ifas.ufl.edu/lso/SpMite/b853a1.htm. Additional information can be found using search engines (see http://mrec.ifas.ufl.edu/cutfol/cutpubs/cfg_00_4.pdf for suggestions on finding information on the Internet). Selective miticides such as those listed in Stamps et al., 1997 should be used. Broad-spectrum insecticides, especially long-lived ones such as pyrethroids, should be avoided.

Nematodes - Japanese pittosporum is very susceptible to root-knot nematodes.

Figure 5. 

Unfortunately, pittosporum is a good host plant for root-knot nematodes (Meloidogyne spp.). Damage to the vascular tissue and loss of root hairs can lead to plant death.


Credit: Robert H. Stamps
[Click thumbnail to enlarge.]

Symptoms - Reduced plant vigor, loss of foliar glossiness, absence of roothairs, clubbing of root tips.

Control - Clean stock should be used and planted into soil that is root-knot free. Since many weeds are hosts for root-knot, they should not be allowed to grow in areas to be planted or between pittosporum bushes after they have been planted. Unfortunately, no nematicides proven to be effective are labeled for use on this crop.

Main diseases: Japanese pittosporum is a host to numerous pathogens, some that can cause serious problems.

Fungal Foliar

Alternaria leaf spot

Figure 6. 

On pittosporum, Alternaria leafspot is fairly easy to identify and control.


Credit: Robert H. Stamps
[Click thumbnail to enlarge.]

Symptoms - Distortion of leaves accompanied by necrotic reddish-brown to black, roundish spots. Damage to immature foliage can result in severe leaf distortion.

Control - Minimize foliar wetting, keep plants pruned out to facilitate air movement, and use appropriate fungicides as needed.

angular (Cercospora) leaf spot

Figure 7. 

Angular leafspot, caused by the fungus Cercospora pittospori, is very common on P. tobira and is so named because the the spots have distinct straight margins due to the presence of veins stopping disease development.


Credit: Robert H. Stamps
[Click thumbnail to enlarge.]

Symptoms - angular light-yellow to green and tan spots with straight borders due to the spread of the pathogen (Cercospora pittospori) being restricted by the veinlets and veins of the leaves.

Control - Keep foliage dry and plants pruned so there is good air flow through the planting. Use fungicides if necessary. Do not use thiophanate-methyl fungicides (3336™, Domain®, Fungo®, SysTec 1998®) alone if both Alternaria and angular leaf spot diseases are present. Thiophanate-methyl does not control Alternaria and, by reducing competition from Cercospora and other fungi, can make Alternaria damage worse.

Rhizoctonia aerial blight

Figure 8. 

Rhizoctonia aerial blight is most serious during hot, wet weather when the fungus can grow from the soil and crop debris up into the plant canopy.


Credit: Ann R. Chase
[Click thumbnail to enlarge.]

Symptoms (most prevalent during hot, wet weather) - Irregular tan spots, cylindrical leaf curl, silky threads (fungal mycelium).

Control - Cut out severely infected stems and treat with a recommended fungicide.

Fungal Soil - [Note: for specific disease control recommendations see http://edis.ifas.ufl.edu/pdffiles/PP/PP12300.pdf [26 March 2013].

Pythium root rot

Symptoms - Poor growth, chlorotic (yellow) foliage, leaf drop, lack of feeder roots, black/dead outer root layers.

Control - Prevent by growing on well-drained soils and not overwatering. Improve drainage at affected sites and use recommended fungicides.

Rhizoctonia root rot

Symptoms - Similar to those for Pythium root rot except for the sloughing off of the outer portion of the roots.

Control - Same as for Pythium root rot.

Additional diseases: Several other fungal pathogens (e.g. Erythricium salmonicolor) can cause galls and dieback. Most of these enter through wounds (from clippers or split bark from cold damage) and are internal and, therefore, generally untreatable using chemicals. Disinfection of clippers and careful pruning of diseased tissue are the only methods of "control." Purchase disease-free stock plants.

Figure 9. 

A serious dieback disease, pink limb blight, caused by Erythricium salmonicolor (formerly Corticium salmonicolor), results in limb dieback and can lead to plant death.


Credit: Ann R. Chase
[Click thumbnail to enlarge.]

Weeds: Weeds compete with pittosporum for light, nutrients, and water and can harbor disease and insect organisms and nematodes.

Symptoms - Plants other than pittosporum or purposely planted companion crops are growing in pittosporum fields.

Control - Cultivation, non-selective herbicide treatments, and use of weed barriers (such as mulches and synthetic ground covers) before planting can prevent many weed problems from occurring. Observations suggest that when plants are stressed due to nematode feeding, ground covers may further inhibit plant growth, possibly by restricting oxygen movement to the already damaged rootzone. Many selective herbicides (http://edis.ifas.ufl.edu/WG058) can be used after planting and/or following the removal of all established weeds to suppress future weed growth. Certain non-selective postemergence herbicides (http;//edis.ifas.ufl.edu/WG059) may also be used as directed sprays to control established weeds.

Common cultural problems:

Magnesium (Mg) deficiency

Figure 10. 

Magnesium (Mg) deficiency occurs on the older foliage first as the Mg is translocated from that tissue to the growing points of the plants.


Credit: Robert H. Stamps
[Click thumbnail to enlarge.]

Symptoms - Marginal chlorosis (yellowing) of older leaves.

Control - Make sure pH is in the proper range (ideally 6.2–6.8) and that Mg is being applied in sufficient quantities to meet crop needs. The most frequently used Mg sources are MgSO4 (epsom salts) and dolomite (dolomitic limestone containing both calcium and Mg). Growers should be aware that dolomite can cause the soil pH to rise, i.e., become more alkaline.

Chlorothalonil fungicide toxicity

Figure 11. 

Repeated applications of chlorothalonil fungicides to P. tobira can cause growth-regulator-like symptoms and leaf drop (plant on left). Plant death, especially of the variegated forms, can even occur.


Credit: Robert H. Stamps
[Click thumbnail to enlarge.]

Symptoms - Chlorosis (yellowing) and drop of lower (older) leaves, reduction in growth, and unusually dark green new leaves that are oriented more vertically than is normal for shade grown leaves.

Control - Prevent this problem from occurring by not applying chlorothalonil fungicides (such as Echo®, Daconil®, Thalonil®) to pittosporum, for which they are not labeled.

Selected References

Chase, A. R. 1992. Efficacy of thiophanate methyl fungicides for diseases of Florida ornamentals. Proc. Fla. State Hort. Soc. 105:182–186.

Conover, C. A. and R. T. Poole. 1980. Effects of light and fertilizer levels on cut foliage production. Proc. Fla. State Hort. Soc. 93:210–212.

Hornsby, A.G., R.H. Stamps, and T.M. Buttler. 1998. Managing Pesticides for Pittosporum Production and Water Quality Protection. http://edis.ifas.ufl.edu/SS038

Hunter, N. T. 1994. The Art of Floral Design. Delmar Publishers, Albany, NY.

Poole, R. T. and C. A. Conover. 1980. Influence of light and fertilizer levels on production and acclimatization of Pittosporum spp. HortScience 15:201–203.

Rixon, J. 1987. Foliages for Flower Arrangements. Carlsen Press, San Jose, CA.

Satterthwaite, L. N. and A. R. Chase. 1985. Rooting media for pittosporum cuttings. Nurserymen's Digest 19(2):76–77.

Stamps, R. H. 1985. Effects of production shade level, foliage maturity, antitranspirants, floral preservative and cultivar on vase life of woody cut foliage crops. Proc. Fla. State Hort. Soc. 98:99–100.

Stamps, R. H. 1987. Major Florida cut foliage crops classified according to floral design and landscape use. Proc. Fla. State Hort. Soc. 100:179–180.

Stamps, R. H., and J. G. Norcini. 2001. Preemergent herbicides for use on ornamental crops. Univ. of Fla., Inst. of Food and Agr. Sci., Central Fla. Res. and Ed. Cntr. Circular OH-094. http://edis.ifas.ufl.edu/WG058

Stamps, R. H., L. S. Osborne and D. K. Rock. 1997. Selected miticides for use on ornamental plants. Univ. of Fla., Inst. of Food and Agr. Sci., Central Fla. Res. and Ed. Cntr. Cut Foliage Research Note RH-97-B.

Stamps, R. H., R. A. Dunn, A. G. Hornsby, D. E. Short and G. W. Simone. 1994. Pesticides labeled for use in commercial pittosporum production in Florida - 1994. Univ. of Florida, Inst. of Food and Agr. Sci., Central Fla. Res. and Ed. Cntr. Cut Foliage Res. Note RH-94-A.

Footnotes

1.

This document is ENH861, one of a series of the Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date February 2002. Reviewed January 2012. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Professor of Environmental Horticulture and Extension Cut Foliage Specialist, Mid-Florida Research and Education Center, 2725 Binion Road, Apopka, FL 32703-8504

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition. All chemicals should be used in accordance with directions on the manufacturer's label. Use pesticides safely. Read and follow directions on the manufacturer's label.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.