Proc. Fla. State Hort. Soc. 107: 192-193. 1994.
ROOT AND SHOOT RESPONSES OF TEN FOLIAGE SPECIES GROWN IN
CUPRIC HYDROXIDE TREATED CONTAINERS
SVEN E. SVENSON1 AND DlANE L. JOHNSTON
University of Florida, IFAS
Fort Lauderdale Research and Education Center
Fort Lauderdale, FL 33314
Additional index words. Root morphology, Chlorophytum, Dra
caena, Ficus, Leea, Radermachera, Peperomia, Schefflera, Spathiphyllum.
Abstract. The influence of cupric hydroxide [Cu(OH)2], formulat
ed as SpinOut™ (Griffin Corporation), applied to interior con
tainer surfaces on the root and shoot growth of 10 foliage
species was studied. Species evaluated were: Chlorophytum
comosum (Thunb.) Jacques (spider plant), Chlorophytum
bichetii (Karrer) Backer (dwarf anthericum), Dracaena fragrans
(L.) Ker-Gawl 'Massangeana' (corn plant), Ficus triangularis L.
'Variegata' (variegated triangle fig), Leea coccinea Planch. (Ha
waiian holly), Radermachera sinica (Hance) Hensl. (China doll),
Peperomia serpens (Swartz.) Loud. 'Variegata' (variegated
trailing peperomia), Peperomia obtusifolia (L.) A. Dietr. (baby
rubber plant), Schefflera actlnophylla (Endl.) Harms 'Amate'
(umbrella tree) and Spathlphyllum Schott 'Supreme' (peace
lily). Root balls were evaluated to determine the degree of con
trol of root growth at the container-medium interface. Cupric
hydroxide completely eliminated root growth at the containermedium interface in two species. Control of root growth for the
remaining species was excellent. Shoot growth responses
were species dependent.
Circling and deflected roots have always been a problem
for the container nursery industry. Matted, kinked, and oth
erwise malformed root systems of plants produced in smoothwalled plastic containers have been associated with increased
mortality, poor mechanical stability, and susceptibility to
drought after transplanting (Burdett, 1978; Nichols and Aim,
1983). Root pruning before transplanting container-grown
plants may eliminate root system deformation, but may also
reduce survival and growth (Geisler and Ferree, 1984; Larson,
1980). The application of copper compounds to interior con
tainer wall surfaces prevents root growth at the container-me
dium interface, and may increase root growth after
transplanting (Arnold and Struve, 1989; Wenny et al, 1988).
Response to copper-treated containers differs among various
ornamental species (Beeson and Newton, 1992; Struve et al.,
1994). Of the over 130 species reportedly studied (Struve et
al., 1994), less than 5% are commonly used as foliage plants.
The objective of this study was to determine if Cu(OH)2
applied to all interior container surfaces would influence cir
cling root growth or shoot growth of 10 species commonly
produced in containers for use as foliage plants.
Florida Agricultural Experiment Station Journal Series No. N-01026. This
project was supported in part by Griffin Corporation, Valdosta, Georgia. Use
of specific products does not imply endorsement by the University of Florida.
The assistance of Bonnie L. Coy is gratefully acknowledged.
'Current address: Oregon State Univ.-NWREC, 15210 NE Miley Rd., Au
rora, OR 97002.
192
Materials and Methods
General experimental procedures are listed in Table 1.
Chlorophytum comosum and Radermachera sinica were potted us
ing uniform seedling liners. Chlorophytum bichetii were potted
using uniform divisions. Dracaena fragrans 'Massangeana'
were potted using unrooted 1.2-m canes (Foremost Foliage,
Miami, FL). Ficus triangularis 'Variegata,' Peperomia obtusifolia,
Peperomia serpens, and P. serpens 'Variegata' were potted using
8-week old uniformly rooted cuttings. Leea coccinea were pot
ted using uniform seedlings grown in 2.7-liter containers.
Schefflera actinophylla 'Amate' and Spathiphyllum 'Supreme'
were potted using uniformly rooted cuttings or tissue culture
liners, respectively (Oglesby Plant Laboratories, Altha, FL).
For all species studied, a pine bark:Florida peat:sand
(5:4:1 by volume) medium was used. Before being filled with
medium, interior container surfaces were left untreated, or
were sprayed with a latex-Cu(OH)2 compound [100 g
Cu(OH)2/liter; approximately 4.6% metallic Cu equivalent),
formulated as SpinOut™ (Griffin Corporation, Valdosta,
GA). Studies were completed in either a black-poly shadehouse providing 63% shading, or in an open-sided, single-lay
er polycarbonate greenhouse shaded (Kool Ray Liquid
Shade, Continental Products, Euclid, OH) to provide approx
imately 63% shading. Plants were subject to natural tempera
ture and humidity conditions prevailing during the time
period of the study (Lat. 26.1N, Long. 80.2W, Fort Lauder
dale, FL). A completely randomized experimental design was
used for all studies.
Root growth covering the exterior of the rootball was eval
uated using the scale: 1 = <20% of the rootball covered with
Table 1. Experimental procedures used for testing the influence of
Cu(OH)2 applied to interior container surfaces on the shoot and root
growth of ten foliage species.
Pot
Botanical Name
Chlorophytum comosum
Chlorophytum bichetii
Dracaena frangrans
'Massangeana'
Ficus triangularis
Fertilizer2
Potting
rate
date
(liter) (g)
size
Weeks
to
Sample
evaluation
0.5y
12
12/29/93v
19
8
0.5y
12
12/29/93v
19
6
5.5x
48
02/24/94v
20
9
8
0.5y
12
12/29/93v
30
Leea coccinea
5.5x
48
11/05/9311
18
8
Peperomia obtusifolia
0.5y
12/29/93v
12/29/93v
19
15
0.5y
12
12
15
15
0.5y
12
12/29/93v
15
15
Radermachera sinica
1.2w
18
Schefflera actinophylla
'Amate'
02/04/92"
12
15
5.5x
70
12/10/91"
16
30
Spathiphyllum 'Supreme'
1.2w
18
04/16/92"
30
10
'Variegata'
Peperomia serpens
Peperomia serpens
'Variegata'
zOsmocote 18N-3.1P-10K (Grace-Sierra, Milpitas, CA).
Container with 11 cm top diameter.
"Container with 22 cm top diameter.
wContainer with 15 cm top diameter.
'Greenhouse study.
"Shadehouse study.
Proc. Fla. State Hort. Soc. 107: 1994.
white root tips, little or no root circling; 3= about 50% of the
rootball covered with white root tips, moderate root circling;
and 5=>80% of the rootball covered with white root tips, ex
Table 3. Shoot dry weights of Leea coccinea and Spalhiphyllum 'Supreme' as
influenced by Cu(OH)2-treatment of interior container surfaces.
Shoot dry weight, g
tensive root circling (Ruter, 1994).
After root coverage was evaluated, plants were harvested
to determine shoot dry weight (dried at 65°C for at least four
days). Data were analyzed for significant response to
Cu(OH)2 using analysis of variance (SAS Institute, 1989).
Botanical Name
Leea coccinea
Spathiphyllum'Supreme'
+Cu(OH)2
-Cu(OH)2
134.2*
108.3
20.7*
25.2
*SignificantatP<0.001.
Results
The influence of Cu(OH)2 application on root coverage
is listed in Table 2. Compared to root growth in untreated
containers, Cu(OH)2 eliminated almost all root growth on
the exterior of the rootballs of Chlorophytum comosum, Chloro-
phytum bichetii, Dracaena fragrans 'Massangeana,' Ficus triangularis
'Variegata,'
Peperomia serpens,
and
Peperomia
serpens
'Variegata,' and completely eliminated root growth on the ex
terior of the rootball of Peperomia obtusifolia and Radermachera
sinica. Although Cu(OH)2 treatment did not completely con
trol root growth on the exterior of the rootballs of Leea coccin
ea, Scheffiera actinophylla 'Amate,' or Spathiphyllum 'Supreme,'
no circling roots longer than l/3 of the circumference of the
rootball were observed.
Application of Cu(OH)2 to interior container surfaces did
not influence shoot dry weights, except for Leea coccinea and
Spathiphyllum 'Supreme' (Table 3). Leea coccinea had more
shoot dry weight, and Spathiphyllum 'Supreme' had less shoot
dry weight, when grown in Cu(OH)2-treated containers com
roots in Cu(OH)2-treated containers have been reported for
a variety of species (Beeson and Newton, 1992; Ruter, 1994;
Struve et al., 1994). Roots were forced to grow within the
growing medium rather than along the container-medium in
terface. For some species in certain container sizes, applica
tion of Cu(OH)2 to interior container surfaces has increased
or decreased shoot growth (Beeson and Newton, 1992; Struve
et al., 1994), which is consistent with the increased shoot dry
weights oiLeea coccinea and the decreased shoot dry weight of
Spathiphyllum 'Supreme' (Table 3).
The use of Cu(OH)2-treated containers when growing fo
liage species eliminates the need to prune roots before trans
planting or upcanning, and may support faster growth after
transplanting (Arnold and Young, 1991). This study shows
that growth responses of foliage species to Cu(OH)2-treated
containers are as variable as the responses reported for tem
perate species, and adds to the list of foliage species that have
been investigated (Case and Arnold, 1992).
pared to untreated containers.
Literature Cited
Discussion
Arnold, M. A. and D. K. Struve. 1989. Growing green ash and red oak in
For all species studied, application of Cu(OH)2 to interior
container surfaces provided excellent control of circling root
growth without reducing shoot growth (except for Spathiphyl
lum 'Supreme'). Similar reductions in malformed, circling
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Table 2. Root coverage of ten species of foliage plants as influenced by
Cu(OH)i;-treatment on interior container surfaces.
486.
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Root coverage'
Botanical Name
+Cu(OH)2
-Cu(OH)2
Chlorophytum comosum
.0*
4.7
Chlorophytum bichetii
.0*
2.2
Dracaena fragrans 'Massangeana'
2.8
Ficus triangularis 'Variegata'
L0*
2.5
.2*
3.1
Peperomia obtusifolia
L.0*
2.4
Peperomia serpens
3.9
Pepeiomia serpens 'Variegata'
L.0*
L.0*
Radermachera sinica
L.0*
4.3
Scheffiera antinophylla 'Amate'
L.I*
3.8
Spathiphyllum 'Supreme'
1.1*
3.4
Leea coccinea
3.8
'Root coverage: l=<20% of rootball covered with white root tips, little or no
root circling; 3=about 50% of rootball covered with white root tips, moder
ate root circling; 5=>80% of rootball covered with white root tips, extensive
root circling.
♦Significant at P<0.001.
Proc. Fla. State Hort Soc. 107: 1994.
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193