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S Utilization of Melaleuca quinquenervia as a Potting Medium
Component for Production of Foliage Plants
C. A. Conover and R. T. Poole .
University of Florida, IFAS
Central Florida Research and Education Center- Apopka
CFREC-Apopka Research Report RH-90-7 2 q(
Large quantities of low quality sedge and highly oxidized sphagnum
peats exist in the United States. This peat is generally unsuitable for
use as growing media unless amended with materials to improve aeration.
Pine bark, vermiculite, perlite, or styrofoam pellets are coarse materials
currently used for this purpose. With these materials becoming more
expensive, there exists a need for more economical substitutes.
Melaleuca quinquenervia (punk or paper bark tree) currently has few
commercial uses. This Australian import, considered a weed in our country,
has invaded over 500,000 acres of southern Florida. Melaleuca can grow on
a wide variety of wet or dry, poor or disturbed soils, crowding out native
plant material and quickly dominating the landscape. Melaleuca bark
comprises up to 50% of the trunk and branch volume and its loose, open
structure makes it a potential coarse material for use in potting mixes.
The experiments that follow were developed to examine the potential use of
shredded Melaleuca bark (MB) and Melaleuca tree mix (MM) as components of
potting media for containerized foliage plants.
MB AND MM SPECIFICATIONS
All Melaleuca bark used was separated from fresh 4 to 6 inch diameter
logs, and individual bark fragments ranged in size from dust to 2 inches
long with most within the 0.4 to 0.8 inch range. Thickness was less than
0.2 inches. Melaleuca tree mix was composed of the entire above-ground
portion of trees measuring 1 to 4 inches in diameter at breast height.
Shredded particle sizes were variable, with bark portions similar to the
bark listed above, and wood portions mostly 0.1 to 0.2 inches in diameter
and up to 2 inches long. Leaf and seed portions of trees were included and
were barely noticeable after shredding. All bark and tree materials used
were fresh, having aged no longer than 8 weeks. All media tested were
first amended with 7 lbs/yd3 dolomitic limestone and 1.5 b/yd3 of Perk or
Micromax (micronutrient blends). Perk, manufactured by Estech General
Chemicals Corporation, Chicago, IL, was used in experiments 1 through 4.
Experiment 5 media contained Micromax, which is manufactured by Sierra
Chemical Co., Milpitas, CA.
1Center Director and Professor and Professor, Plant Physiology,
respectively, Central Florida Research and Education Center, 2807 Binion
Road, Apopka, Florida 32703
Two experiments compared artificial media composed of sedge peat (P),
Solite (SO), [a fired Montmorillonite clay particle sized about 0.5 inch,
produced by the Solite Corp. of Richmond, VA.], MB and MM, against 3 peat:l
sand (P:S). Experiment 1 utilized 6 to 8 inch liners of Ficus benjamin
(weeping fig) and Dracaena marginata (Madagascar dragon tree-)potted into 6
inch standard pots. The five potting mixes examined were (1) 3P:1S, (2)
3P:1SO, and (3-5) P:MB:SO in mixtures of 2:1:1, 1:2:1, and 2:1:1 by volume.
Six month release rate 18-6-12 Osmocote fertilizer was surface applied at
time of potting, Jan. 4, at rates of 3.3 or 6.6 grams per pot. Osmocote
fertilizer is manufactured by Sierra Chemical Co., Milpitas, CA. Plants
were grown under 47% polypropylene shadecloth where they received a maximum
of 6000 ft-c natural light. Temperatures ranged from 450F to 1000F.
Plants were watered once or twice weekly.
On Sept. 2, plant height was measured and plant quality graded on a
scale of 1-5 with 1 = poor, not salable; 3 = good, salable; and 5 =
excellent quality. Color grade was rated on a 1-5 scale with 1 = light
green; 3 = medium green and 5 = dark green.
Different media had less effect on plant grade of Dracaena than that
of Ficus. Where MB constituted 50% of the potting mixture, as in the
1P:2MB:1SO, plant height and grade of both Ficus and Dracaena were
smallest. Where MB made up only 25% of the mix, growth of both plants
compared favorably with the 3P:1S standard (Table 1). Doubling fertilizer
levels increased height of Dracaena.
Experiment 2 involved growing rooted tip cuttings of Ficus benjamin
and Dracaena marginata, one per 6-inch standard pot. Medium treatments
included (i) 3P:1S, (2) 3P:1SO, (3) 2P:1SO and (4-6) P:MM:SO in mixtures of
1:1:1, 2:2:1, and 1:2:1 by volume. Fertilizer rates of 4, 8, or 12 grams
per pot Osmocote 14-14-14 fertilizer were surface applied Nov. 25, at time
of potting. Plants were refertilized 5 months later with 19-6-10 Osmocote
at rates of 3.3, 6.6, or 9.9 grams per pot. Plants were grown under 47%
polypropylene shadecloth, receiving 6000 ft-c maximum natural light.
Temperatures ranged from 450F to 1000F and plants were irrigated twice
weekly. Plant growth data recorded after 8 months for Ficus included
height and plant grade, and for Dracaena, height, plant grade, fresh top
and root weight.
Growth of Ficus was not affected by media or fertilizer levels (Table
2). Height of Dracaena was greatest in the 3P:1S mix, while plant grade
was equal in the 3P:1S, 3P:1SO, 2P:1SO, and 1MM:1SO media. No differences
in top or root weights were observed on Dracaena grown in these mixes. As
in experiment 1, 1P:2MM:1SO was a poor mix for Dracaena, especially when
compared with the 3P:1S standard. Increasing fertilizer levels increased
top weight, height, and plant grade of Dracaena. Lack of interactions
found in plants' response to the medium-fertilizer combinations tested
shows increases in fertilizer levels would not correct problems observed
with the Melaleuca containing mixes (Table 2 significant effects MxF).
Shorter plants, and lower plant grade of Dracaena appear to be caused by
too much non-capillary pore space (aeration) and lowered water-holding
capacity of the soil mix.
Experiment 3 was conducted to determine growth response of Ficus
benjamin (weeping fig) in various combinations of peat, sand, Melaleuca
bark, and Melaleuca tree mix, irrigated at different frequencies.
Twenty-two inch Ficus plants growing one per pot, in 6 inch pots containing
3 Florida sedge peat:l builder's sand by volume, were repotted into 10 inch
containers on June 16, using the twelve listed potting medium combinations
(Table 3). Containers were surface treated with 9 grams per pot 18-6-12
Osmocote fertilizer every three months, for a total of 3 times. Plants
were grown in a polypropylene shadehouse where they received 4500 ft-c
natural light. Temperatures ranged from 540F to 950F and plants were
watered 2 or 4 times per week.
On Feb. 10, plants were sleeved, boxed, and placed in coolers with
550F temperature and 85% RH (relative humidity). Plants were removed from
shipping chambers after 4 weeks and placed in rooms where they received 75
ft-c light from cool white fluorescent lamps 12 hours daily. Temperature
was maintained at 770F and RH was 60%. Plants were watered once a week or
Data recorded May 27, on termination of experiment 3, included height,
fresh weight and plant grade as in experiment 1, and root grade (based on a
quality scale of 1-5 where 1 = 0-20%, and 5 = 81-100% root ball coverage).
Plant height was not affected by percentage of MM in soil mix, but
percentage of MM in mix did influence other plant characteristics. Fresh
weight, plant grade, and root grade increased as Melaleuca content of the
media decreased. More frequent waterings increased fresh weight and root
grade, but did not affect plant grade or height (Table 4).
These results agree with experiments 1 and 2, suggesting media
composed of no more than 25% by volume MB and/or MM can be used to grow
good quality foliage plants if other media components do not have a high
Experiments 4 and 5 examined the potential use of shredded Melaleuca
tree mix and/or Melaleuca bark as components of growing media for
greenhouse production of foliage plants, and compared MB and MM mixes to a
2 sedge peat:l pine bark:l cypress shavings mix. Both experiments used
Aglaonema commutatum 'Fransher' (Fransher aglaonema) and Nephrolepis
exaltata 'Fluffy Ruffles' (Fluffy Ruffle Boston fern) potted in 6 inch
Experiment 4, initiated Mar. 5, compared four potting mixes: (1) 2
Florida sedge peat:l pine bark:l cypress shavings (SP:PB:CS) and (2-4)
Florida sedge peat:Melaleuca bark (SP:MB) in mixtures of 1:1, 3:1, and 1:3
by volume. Plants were fertilized with 3.5 or 7.0 grams per pot 18-6-12
Osmocote and watered 2 or 4 times weekly. Plants were placed in a glass
greenhouse where they received a maximum of 1200 ft-c natural light.
Temperatures ranged from 64F to 900F.
Plant growth data for Boston fern, recorded after 3 months, included
plant height and plant grade, based on the same scale as experiment 1, and
number of runners (Table 5). Boston fern grew equally well in all media
and fertilizer levels had no effect on growth. Height, plant grade, and
number of runners produced were greater when watered 4 rather than 2 times
per week, but earlier research has also shown that Boston fern responds
positively to increased watering levels.
Growth data recorded for Aglaonema after 6 months included height,
plant grade, and number of basal breaks (shoots) greater than 1 inch tall.
Height and grade of Aglaonema were unaffected by treatment. Lack of
interactions in this experiment show the wide range of conditions under
which these Melaleuca bark mixes could be useful in greenhouse production.
In experiment 5, initiated Feb. 5, Aglaonema and Boston fern watering
and fertilizer treatment rates were similar to experiment 4 except 19-6-10
Osmocote Sierrablen fertilizer replaced 18-6-12 Osmocote. Seven media were
compared: (1) 2 Florida sedge peat:l pine bark:1 cypress shavings, (2-4)
Florida sedge peat:Melaleuca bark in mixtures of 1:1, 1:2, and 2:1 by
volume, and (5-7) Florida sedge peat:Melaleuca tree mix in combinations of
1:1, 1:2, and 2:1 by volume. Plants were grown in glass greenhouses under
the same conditions as experiment 4.
Plant growth data recorded at 4 months for Boston fern included plant
height, plant width, and plant grade as in experiment 4 (Table 6). Growth
data recorded for Aglaonema at 6 months included height, plant grade, and
number of basal breaks greater than one inch tall.
Height and plant grade of Boston fern, and plant grade and number of
shoots on Aglaonema were not affected by media. Plants in mixes containing
more than 50% MB or MM were slightly shorter (Aglaonema) or not as wide
(Boston fern). Doubling fertilizer rate from 3.5 grams to 7.0 grams per
pot increased slightly all growth measurements for Boston fern and
Aglaonema but may not be economically worthwhile. Lack of significant
irrigation interactions (Table 6 significant effects) shows responses to
increased watering relate to all mixes tested and may be due to their high
Experiment 4 and 5 data show MB and MM have great potential for
increasing aeration in potting media. Mixes containing more than 50% MB or
MM by volume produced the smallest plants probably because aeration levels
were too high and the medium dried too rapidly.
Data from all 5 experiments show MB and MM can serve as a component of
media used to produce high quality shadehouse and greenhouse grown foliage
plants. Up to 50% by volume MB or MM may be used when other components of
media have poor aeration and high water-holding capacity. When builder's
sand or other materials having a lower water-holding capacity make up to
25% of the growing media by volume, Melaleuca bark or Melaleuca tree mix
,should not exceed 25% by volume.
Melaleuca bark and Melaleuca tree mix have potential for use in the
container plant industry but are not currently being used by most potting
mix manufacturers. This situation will continue unless producers ask the
potting mix industry to supply mixes containing melaleuca products.
Some of the advantages to using Melaleuca bark and/or Melaleuca tree
1. Melaleuca's excellent aeration characteristics allow it to be used
with high or low quality peat moss.
2. The decomposition rate of Melaleuca is about the same as cypress
shavings and pine bark.
3. Melaleuca bark and/or Melaleuca tree mix can be used as a
substitute for pine bark. This is especially advantageous for
growers shipping foliage plants to Europe since melaleuca meets
quarantine requirements and pine bark does not.
4. Melaleuca trees are a renewable resource in south Florida where
pine bark is in short supply.
1. Conover, C. A. and R. T. Poole. 1983. Sedge moss peat, solite, and
Melaleuca quinquenervia as potting medium components for shadehouse
production of foliage plants. HortScience 18:888-890.
2. Conover, C. A. and R. T. Poole. 1983. Utilization of Melaleuca
quinquenervia as a potting medium component for greenhouse production
of foliage plants. HortScience 18:886-888.
3. Ingram, D. L. and C. R. Johnson. 1982. Melaleuca bark as a container
medium component. Univ. of Fla. IFAS, Orn. Hort. Rpt.
4. Poole, R. T. and C. A. Conover. 1979. Melaleuca bark and solite as
potential potting ingredients for foliage plants. Proc. Fla. State
Hort. Soc. 92:327-329.
5. Poole, R. T. and C. A. Conover. 1985. Growth of Ficus benjamin in
combinations of peat, sand, and Melaleuca. HortScience 20:383-385.
6. Poole, R. T. and W. E. Waters. 1972. Evaluation of various potting
media for growth of foliage plants. Proc. Fla. State Hort. Soc.
Table 1. Influence of potting media, fertilizer, and irrigation levels on
shadehouse grown Ficus benjamin and Dracaena marginata. Experiment 1
Ht grade Ht grade
Variable (in) rating (in) rating
3P:1S 35.5 4.6 25.4 3.7
3P:1SO 36.5 4.5 25.6 3.9
2P:2MB:1SO 34.2 4.2 24.4 3.7
1P:2MB:1SO 30.8 3.7 24.1 3.6
2P:1MB:1SO 32.8 4.3 24.5 3.7
3.3 34.0 4.0 23.7 3.5
6.6 33.9 4.5 25.9 4.0
l/week 34.6 4.2 24.3 3.6
2/week 33.4 4.3 25.3 3.9
Media ** ** NS *
Fertilizer NS ** ** **
Irrigation NS NS **
MX F NS NS NS **
ZMedia composed of P = peat, S = sand, MB = melaleuca bark, and SO = solite
Y1 = poor, not salable; 3 = good, salable; 5 = excellent quality.
xNS,*,**Nonsignificant (NS), or significant at 5% (*) or 1% (**) level.
Table 2. Influence of potting media and fertilizer on shadehouse grown
Ficus benjamin and Dracaena marginata. Experiment 2
8 mo 6 mo
Plant Plant Top Root
Ht grade Ht grade wt wt
Variable (in) rating7 (in) rating oz oz
3P:1S 32.6 3.9 25.9 4.2 7.2 6.1
3P:1SO 33.7 4.2 23.2 4.0 6.6 6.3
2P:1SO 32.7 4.2 23.1 3.9 6.3 6.5
1P:1MM:1SO 33.4 4.1 22.3 3.8 6.2 7.3
2P:2MM:1SO 33.5 4.3 21.8 3.5 5.9 6.6
1P:2MM:1SO 33.3 4.0 21.3 3.3 5.7 6.2
4 32.4 3.9 20.8 3.0 5.5 6.4
8 33.3 4.1 23.5 4.0 6.2 6.2
12 33.9 4.4 24.5 4.4 7.2 6.9
Media NS NS ** ** NS NS
Fertilizer NS NS L**Q* L** L** NS
MX F NS NS ** NS NS NS
zMedia composed of P = peat, S = sand, SO
(tree) mix by volume.
Y1 = poor, not salable; 3 = good, salable;
x14-14-14 at 4, 8, 12 grams/pot initially,
grams/pot, 5 months later.
NS,*,**Nonsignificant (NS) or significant
linear; Q = quadratic.
= solite, and MM = melaleuca
5 = excellent quality.
19-6-10 at 3.3, 6.6, 9.9
at 5% (*) or 1% (**) level, L =
Table 3. Media evaluated (percentage by volume).
Florida Melaleuca Builders'
Medium sedge peat wood products sand
1 45 50 5
2 55 40 5
3 65 30 5
4 75 20 5
5 40 50 10
6 50 40 10
7 60 30 10
8 70 20 10
9 35 50 15
10 45 40 15
11 55 30 15
12 65 20 15
Table 4. Response of Ficus
frequency. Experiment 3
benjamin to potting media and irrigation
Treatment Ht. Fresh Plant Root
% by vol (in) wt (oz) grade" gradey
20 65.7 23.0 4.5 4.8
30 64.5 22.1 4.4 4.7
40 62.2 20.0 4.0 4.4
50 63.3 19.9 3.8 4.5
5 64.9 21.6 4.3 4.5
10 63.7 21.4 4.1 4.6
15 62.9 20.7 4.1 4.5
2 63.3 20.1 4.2 4.5
4 64.5 22.4 4.1 4.7
z1 = poor, not salable; 3 =
yl = 0-20%, 3 = 41-60%, and
good, salable; and 5 = excellent quality.
5 = 81-100% root ball coverage with white
Table 5. Influence of artificial media, fertilizer, and irrigation level
on greenhouse-grown Aglaonema and Nephrolepis. Experiment 4
Aglaonema (6 mo) Nephrolepis (3 mo)
Ht gradey No. Ht gradey No.
Mediaz Ratio (in) rating shoots (in) rating runners
SP:PB:CS 2:1:1 17.7 3.7 4.6 17.0 3.7 10.7
SP:MB 1:1 18.1 3.5 4.4 17.4 3.8 11.9
SP:MB 3:1 18.3 3.9 5.4 16.8 3.8 10.6
SP:MB 1:3 17.4 3.8 4.0 16.3 3.9 10.1
3.5 17.7 3.6 4.2 16.9 3.8 11.9
7.0 18.1 3.9 5.0 16.7 3.8 9.7
2 17.6 3.6 4.4 15.8 3.2 7.3
4 18.2 3.9 4.8 17.9 4.4 14.3
Media NS NS NS NS NS
Fertilizer NS NS NS NS NS
Irrigations NS NS NS ** ** **
"Media composed of SP = s
and MB = melaleuca bark.
edge peat, BP = pine bark, CS = cypress shavings,
'1 = poor, not salable; 3 = good, salable; and 5 = excellent quality.
XFrom 18-6-12 6 month Osmocote.
wNS,*,**,***Nonsignificant (NS) or significant at 5% (*), 1% (**), or 0.1%
Table 6. Influence of artificial media, fertilizer, and irrigation level
on greenhouse-grown Aglaonema and Nephrolepis. Experiment 5
Aglaonema (6 mo) Nephrolepis (4 mo)
Plant Plant Plant
Ht grade No. Ht width grade
Mediaz Ratio (in) ratingy shoots (in) (in) rating
SP:PB:CS 2:1:1 18.0 3.4 3.1 21.8 25.1 4.4
SP:MB 1:1 18.8 3.6 3.4 23.0 26.4 4.5
SP:MB 1:2 17.5 3.1 3.2 22.4 24.4 4.2
SP:MB 2:1 18.0 3.6 3.4 22.9 25.2 4.3
SP:MM 1:1 18.3 3.5 3.4 24.3 25.5 4.4
SP:MM 1:2 17.3 3.4 3.5 21.2 24.1 4.1
SP:MM 2:1 17.6 3.6 3.4 22.7 25.1 4.4
3.5 17.3 3.2 3.2 22.1 24.5 4.2
7.0 18.5 3.8 3.5 23.2 26.6 4.5
2 17.8 3.4 3.2 20.8 24.5 4.1
4 18.1 3.6 3.4 24.4 26.6 4.6
Media ** NS NS NS NS
Fertilizer ** ** ** ** *
Irrigations NS NS ** ** **
Media x irrigation NS NS NS NS NS
zMedia composed of SP = sedge peat, PB = pine
MI ma= l1 -1 b kL-. r nAl MM hla l1 ia.t- m v
bark, CS = cypress shavings,
1 = poor, not salable; 3 = good, salable; 5 = excellent quality.
XFrom 19-6-10 Osmocote.
WNS,*,**Nonsignificant (NS) or significant at 5% (*) or 1% (**) level.
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