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Copyright 2005, Board of Trustees, University
ENVIRONMENTAL FACTORS INFLUENCING LONG-TERM
SHIPPING OF TROPICAL FOLIAGE PLANTS-- --------
C. A. Conover and R. T. Poole n
University of Florida, IFAS "
Agricultural Research Center
Research Report RH-1983-3 .A.S. Univ of Flori_;::_
Movement of tropical foliage plants in international commerce is
becoming more important as energy costs escalate. Rapid fuel cost increases
have made high temperature requiring crops, such as Codiaeum, Dracaena,
Aglaonema, Dieffenbachia, Ficus and many others, prohibitively expensive for
cold climate growers to produce in larger sizes. Ten years ago foliage
stock plant producers in the United States and Europe started moving plantings
to Central and South America and Africa in an attempt to maximize utilization
of expensive greenhouse space (3,4). Most cuttings and plant parts produced
in tropical and subtropical climates were shipped by air freight because of
their perishable nature. This shipping system seldom resulted in more than
two days transit time and most plant material reached the marketplace in
excellent condition (5).
With continued escalation of fuel energy costs, growers in northern
climates have become interested in producing crops with lower energy
requirements, or those that turn over faster to achieve greater number of
units. Foliage plants in pot sizes of 6 inches or greater do not fit this
model and have caused northern producers to become disinterested in supplying
these products. Plant brokers, wholesalers and retailers, however, find
increasing interest by consumers in larger sized foliage plants and have
looked forward to the possibility of growing material in warmer climates and
shipping to cold climate zones. Larger sized foliage plant products, though,
are not economical when shipped by air and, if this were the only shipping
system, would not be cost effective. Shipping by sea is more cost effective,
but usually only for bulky, heavy commodities. And since sea shipments
involve longer time durations from major subtropical and tropical production
areas, often two to three weeks, plant quality has been unsatisfactory,
especially in trial shipments made during the last few years.
Beginning in the early 1970s, research on improving interior survival
of foliage plants has been conducted in the U.S., primarily in Florida-
(2,8,9,13,17). Although the original objective was to delineate production
factors which influence interior plant quality, observations showed
acclimatization had a direct effect on shipping (16,18). Two major factors
found to influence acclimatization were light intensity during production
and fertilizer level. Subsequently,'recommendations were developed on
acclimatization (10) for major foliage plant genera and are in general use
in the U.S. today (Table 1). Use of Table 1 data for production of specific
foliage plant genera, however, varies with the growing environment. Some
major factors influencing the fertilizer level include light intensity,
temperature, rainfall or irrigation level and cation exchange capacity of the
Initially, development of long-term shipping procedures included periods
up to 14 days, but was increased under simulated conditions to 28 days. All
plant material utilized in simulated 0 to 28 day shipping trials were
acclimatized according to recommendations (10) and were of high quality prior
to placement under simulated shipping conditions.
Simulated shipping conditions were achieved by utilizing refrigeration
units with temperatures controlled within 1F. Humidity was not controlled
within refrigeration units, but was 90 5% within shipping boxes and
considered standard at various temperatures utilized. All foliage plants in
these trials were watered the day before sleeping, boxing and placement into
simulated shipping units. The various foliage genera tested were held for 7,
14, 21 or 28 days at 50, 55, 60 or 650F, after which they were removed and
placed under an interior environment of 15 umol sec m (150 ft-c) from Cool
White fluorescent lamps for 12 hours daily, a temperature of 770F, relative
humidity of 60 10% and irrigation as needed (1 or 2 times per week).
All plants were rated at removal and 60 days after removal from
simulated shipping conditions, although only 60-day data are presented
(Table 2). Plants with grades of 3.5 or higher would be required to meet U.S.
or European quality standards.
Plant quality of all genera tested except Dracaena marginata and
Chrysalidocarpus lutescens was acceptable at one or more temperatures even
after 28 days of simulated shipping (Table 2). Schefflera arboricola
shipped best at 50F and Aglaonema 'Fransher' at 55, 60 or 650F. Dracaena
marginata and Chrysalidocarpus lutescens generally shipped well for periods
up to 21 days at 55, 60 or 650F.
Problems observed with plants shipped for long periods at 650F included
yellowing of newer terminal foliage due to continued growth in the dark and
loss of lower foliage on Ficus and Dracaena.
Chrysalidocarpus, Aglaonema and Dracaena shipped at 500F for longer
periods showed evidence of chilling damage. This was particularly noticeable
after.21 days, but was also a problem on Aglaonema after 14 days. Foliage
plant quality of all genera would have been acceptable by U.S. and European
standards after 14 to 21 days in the dark at 55 to 600F. The major problem
of drying and leaf abscission previously noted (1,15) was not observed even
after plants were in boxes for periods up to 28 days. In fact, because of the
high humidity maintained in the sealed boxes, the potting medium was still
quite moist when plants were finally removed.
Subsequent to the experiments outlined above, we had the opportunity to
conduct a simulated shipment on an entire 40-ft container of foliage plants
as a preliminary to the intended U.S. Floriade exhibit shipment (7,11). This
simulated shipment tested effects of packing methods (boxed, sleeved and open)
and plants from different producers on post shipping quality. The container
was sealed (zero air exchange) for 18 days and maintained at 55 10F. Plant
material used in this test ranged in size (from 3 to 23 feet tall), as did
container diameter (from 10 inches to 6 feet). Results of plant grade change
from 18 days simulated shipment are provided in Table 3. Plant quality
remained very high, with quality reductions noted on Pleomele and Dracaena
probably related to chilling injury rather than to light exclusion.
Data from the Floriade test shipment and research discussed previously
were subsequently utilized to ship four 40-foot containers of large foliage
plants to the Floriade exhibit in The Netherlands (6) (Table 4).
Although many aspects of long-term shipping of foliage plants still
need to be elucidated, the simulated shipping experiments and actual
shipments show long-term shipping is possible; however, several important
points are crucial for delivery of high quality merchandise.
Acclimatization Foliage plants properly acclimatized under recommended
light and fertilizer regimes tolerated long-term shipping better than plants
not conditioned. These plants should also have highly developed root systems
and be free of insect, mite and disease pests.
Shipping Temperature Our research and shipping tests have shown best
shipping temperatures varied for different plant genera and for different
shipping durations. Apparently, 650F, the commonly used shipping temperature,
fine for some plants in short-term (up to 14 days) shipments, but considerable
yellowing of terminal foliage does occur. A shipping temperature as low as
50F has been excellent for dwarf schefflera, but causes chilling damage on
many other genera. Suggestions on best shipping temperatures for a wide
range of foliage plants can be found in ARC-Apopka Research Report RH-83-1.
Humidity Research and the Floriade shipment experience showed the
effects of humidity during long-term shipping. Humidity levels in the range
of 90 5% are feasible with present shipping containers, provided they are
sealed and little or no air exchange occurs. These humidity levels preclude
leaf loss from desiccation.
Ethylene This has not proven to be a problem in our simulated
shipments or in the Floriade shipments; however, our plants were of good to
excellent quality and not influenced by insects, mites or diseases which might
influence ethylene generation. Research by others (12,14) have shown low
levels of ethylene are not damaging to foliage plants.
In summary, these data appear to indicate long-term shipping of tropical
foliage plants will become a major factor in the marketplace in the future.
1. Ben-Jaacov, J., R.T. Poole and C.A. Conover. 1982. Effect of nutrition
and soil water content on storage of Dieffenbachia maculata (Lodd.) G.
Don 'Rudolph Roehrs'. HortScience 17:(In Press).
2. Collard, R.C., J.N. Joiner, C.A. Conover and D.B. McConnell. 1977.
Influences of shade and fertilizer on light compensation point of Ficus
benjamin L. J. Amer. Soc. Hort. Sci. 102:447-449.
3. Conover, C.A. 1972. The ornamental horticulture industries, research and
teaching programs of the United States Gulf Coast Region. Proc. Conf. on
Hort. Dev. in the Caribbean. Maturin, Venezuela, March 12-15, 1972. pp
4. Conover, C.A. 1974. Production and research on tropical foliage plants in
the Americas. Proc. 19th Int. Hort. Cong. Warsaw, Poland. 4:169-178.
5. Conover, C.A. 1976. Postharvest handling of rooted and unrooted cuttings
of tropical ornamentals. HortScience 11:127-128.
6. Conover, C.A. 1982. Floriade shipping setup and results. Fla. Nurseryman
29(7): (In Press).
7. Conover, C.A. 1982. Floriade test shipment. Fla. Nurseryman 29(4):28-31.
8. Conover, C.A. and R.T. Poole. 1975. Acclimatization of tropical trees for
interior use. HortScience 10:600-601.
9. Conover, C.A. and R.T. Poole. 1975. Influence of shade and fertilizer
levels on production and acclimatization of Dracaena marginata. Proc. Fla.
State Hort. Soc. 88:606-608.
10. Conover, C.A. and R.T. Poole. 1981. Basic fertilization guide for
acclimatized foliage plants. Florists' Rev. 168(4360):10,11,29-32.
11. Conover, C.A. and R.T. Poole. 1982. Results of the Floriade test shipment.
Fla. Nurseryman 29(4):28-29.
12. Cunningham, J.L. and G.L. Staby. 1975. Ethylene and defoliation of orn -..
lime plants in transit. HortScience 10:174-175.
13. Fonteno, W.C. and E.L. McWilliams. 1978. Light compensation points and
acclimatization of four tropical foliage plants. J. Amer. Soc. Hort. Sci.
14. Marousky, F.A. and B.K. Harbaugh. 1979. Interactions of ethylene, tempera-
ture, light and C02 on leaf and stipule abscission and chlorosis in
Philodendron scandens subsp. oxycardium. J. Amer. Soc. Hort. Sci. 104:,
15. Peterson, J.C., J.N. Sacalis and D.J. Durkin. 1980. Promotion of leaf
abscission in intact Ficus benjamin by exposure to water stress. J. Amer.
Soc. Hort. Sci. 105:788-793.
16. Poole, R.T. and C.A. Conover. 1979. Influence of shade and nutrition during
production and dark storage simulating shipment on subsequent quality and
chlorophyll content of foliage plants. HortScience 14:617-619.
17. Poole, R.T. and C.A. Conover. 1980. Influence of light and fertilizer
on production and acclimatization of Pittosporum spp. HortScience 15:2
18. Poole, R.T. and C.A. Conover. 1982. Influence of cultural conditions on
simulated shipping of Ficus benjamin. Proc. Fla. State Hort. Soc. 95:(In '
Table 1. Suggested light intensities and nutritional levels for production
of some potted acclimatized foliage plants.
Dracaena deremensis (cultivars)
Dracaena fragrans (cultivars)
(lb/1000 sq ft/yr)
N P205 K20
28 9 19
28 9 19
41 14 27
28 9 19
34 11 23
34 11 23
28 9 19
.28 9 19
28 9 19
28 9 19
41 14 27
41 14 27
41 14 27
28 9 19
28 9 19
Table 2. Influence of simulated shipping duration and temperature on plant
60 days after shipping.
Duration Temp Schefflera Ficus
(days) (oF) arboricola benjamin
7 65 4.2
7 60 4.8
7 55 4.3
7 50 4.7
Chrysalidocarpus Dracaena Aglaonema
lutescens marginata 'Fransher'
Z1 = poor with numerous
5 = excellent quality.
small deformed leaves, 3 = average quality but salable,
Table 3. Change in plant quality
(18 day simulated shipment set
from preshipment to 10 days postshipment
at 550F, no air exchange).
Plant name Preshipment 10 days postshipment
Ardisia crispa -4.5 4.5
Chamaedorea elegans 4.5 4.0
Chrysalidocarpus lutescens 4.5 4.5
Cordyline terminalis 3.5 3.5
Dracaena deremensis 'Janet Craig' 4.0 3.5
Dracaena deremensis 'Warneckii' 4.7 4.5
Dracaena fragrans 'Massangeana' 4.0 4.0
Dracaena marginata 4.5 4.5
Ficus benjamin 4.5 4.3
Philodendron selloum 4.0 3.5
Phoenix roebelenii 4.5 4.5
Pittosporum tobira 'Variegata' 3.7 3.7
Pleomele reflexa 4.7 3.7
Rhapis excelsa 3.5 4.0
Schefflera arboricola 4.5 4.5
Spathiphyllum 'Mauna Loa' 4.0 4.0
z1 = poor with numerous small
5 = excellent quality.
deformed leaves, 3 = average quality but salable,
Table 4. Floriade shipments Sealand Container #120485 set at 550F, no air
Pot Approx. Color gradeY Plant gradex
size height Pre- 7 days Pre- 7 days
Plant material (in) (ft) shipment postshipment shipment postshipment
actinophylla 30 18-19 4.0 4.0 4.0 4.0
seifrizii 18 6 4.5 4.5 4.5 4.5
nitida 36 18 4.0 4.0 4.5 4.5
japonicus 6 0.33 3.5 4.0 4.0 4.0
wrightii 36 18-24 4.5 4.5 5.0 5.0
selloum 14 3 4.0 4.0 4.0 4.0
excelsa 18 7 4.5 4.5 4.5 4.5
arboricola 14 6 4.5 4.5 4.5 4.5
'Mauna Loa' 14 4 4.0 4.0 4.0 4.0
ZLoaded Ft. Lauderdale, FL USA 3/15/82. Unloaded Amsterdam, The Netherlands 3/27.
Y1 = light green, 3 = moderate green, 5 = dark green color.
xl = poor with numerous small deformed leaves, 3 = average quality but salable,
5 = excellent quality.