RESEARCH RESULTS for NURSERYIEN
Tok Furuta.
J. C. Martin, Jr.
Fred Perry
Hlorticulture Series No. 5
AGRICULTURE EXPERIIIENT STATION
E. V. Smd th, Director Auburn, Alabama
RESEARCH RESULTS for NURSERYMEN
NO, 5
CHE ICAL CONTROL of GROWTH
GROWTH RETARDANTS:
Stem elongation of Roundleaf Japanese Holly,-Gardenia, and Burford
Holly plants was retarded by growth retardants B-nine and Cycocel
applied in August. One application of 0.5% spray of B-nine was more
effective than Cycocel at the same concentration. Foliar discoloration
(irregular yellowing of the new foliage chiefly confined to the edges)
indicative of toxicity was noted on Roundleaf Japanese Holly and Gardenia
plants when treated with 0.5% Cycocel. Soil applications were also effect-
ive on these plants.
AZALEA - DAYLENGTH, LIGHT INTENSITY, and GROWTH RETARDANT:
The influence of daylength and light intensity on the effectiveness
of growth retardants was studied. Plants of the Coral Dell and Salmon
Beauty varieties were pinched in June and treated with retardants in -
July. Light intensity treatments for summer growing varied from full sun-
light to 50% reduction. The influence of shortening the daylength to
9 hours in August was also studied.
Plant-shape. Compact plants resulted from shortening the daylength
in August, increasing the light intensity during the summer, or using the
retardants B-nine or Cycocel. There was only slight interaction of these
factors. Cycocel-was more effective than B-nine on the variety Salmon
Beauty, whereas B-nine was more effective than Cycocel on the variety
Coral Bell.
Time of flQoering. Light intensity and daylength interacted to influence
flowering date. Shortening the daylength in August delayed flowering of
plants grown in full sunlight during the summer, and hastened flowering 
of
plants growm under 50% light reduction. When a light shade (25% reduction)
was used, daylength did not influence flowering date.
Daylength also interacted with growth retardants to influence flower-
ing date. For plants grown-under normal daylengths, use of retardants
delayed flowering. -However, when the plants were subjected to shortened
daylength in August, use of retardants did not delay flowering.
Increasing the light intensity during the summer resulted in delayed
flowering. Use of retardants did not influence this reaction.
Number of flowers. Use of retardants resulted in more flowers and in-
creased uniformity of flowering. The other factors did not influence the
number or uniformity of flowering.
AZALEA - EFFECTS OF COLD STORAGE, TI W, AND DURATION:
To study the time and the length of cold storage on flowering of
Azalea plants treated with retardants, cooperative studies were con-
ducted at the Ornamental Horticultural Field Station, Mobile, the
-2 -
.lackwell Nursery, Semes, Rose 
9
nt Greenhouses, -Montgomery, 
and the
Dept. of Horticulture, Auburn, Alas~' Plants of Hexe, Red Wing, Chimes,
and Coral Bell were sheared in June and treated in July. Cycocel and
B--nine were used as foliar sprays at various concentrations. Plants were
stored and forced at Mobile, Iiontgomery, and Auburn.
Only results of the plants stored and forced at Auburn are reported
here.
Influ ences of et.d. ts onshane of thelis.Normally Azaleas
grown in southern Alabama develop many wild shoots late in the sumner.
These extremely vigorous shoots develop from the basal portions of a
plant and cat ibuthtto an uneven crown. Flower buds initiate on these
shoots late in the sumner and are often irmature when the plants are
cooled for early forcing. This delay of flower bud initiation results
in delayed authesis of the flowers, contributing to uneven flowering
often described as undesirable for early forced pot Azaleas.
There was a difference in effectiveness of the retardants depending on
the variety studied. B-nine was more effective thanCycocel in ensuring
compact, uniform crown development Won the CoralBell, Hexe, and Red Wing
varieties. Both retardants were equally effective on the variety Chimes.
With this variety there was little visual difference between the treated
and controlled plants. The difference in plant shape was not too pro
nounced in the Red Wing and Heexe varieties. Only with Coral BeUlwere
there striking differences in crown formation or compactness.
Increasing concentration of both retardants resulted in increased
compactness. At the time the plants arrived at Auburn, the concentration
of each retardant that seemed to produce the best shaped crown were as
follows:
ar. ty B.nine 
Cv
Coral Bell ........ , 0.20% 3-ozj.gallon
Hexe .. . .... .. 0. 20% 2-3 oz,./gallon
Chimes .. ,,......... All treatments appearedi about the same
Red Wing .......... All about the same 2-3 oz./gallon
D mae duri .s-tor _ e nr cd. Only with the variety Coral Bell
stored from Sept. 12 to Nov.. 12 were storage difficulties experienced.
A ft ev rproxmtey6 ekso-tA r. 1,rKvrA P noage, foliag.,eijye gan 1%I '~to apparr
Cooperation of Dr. Raymond L. Self, Pathologist in charge of the
Ornamental Horticulture Field Station, Oren Blackwell and Owen
Blackwell., Jr.., Blackwell Nurseries, and W, W, Paterson, Rosemont
Gardens is gratefully acknowledged.
Retardant use did not increase or decrease the severity of the
foliage injury.
Gibberallic .acid and fiowerin . (1) Without refrigerated 
storage
only the variety Chimes flowered uniformily enough to be considered
salable when the plants were treated with gibberellic acid beginning on
Sept. 19. Maximum flowering occurred about Dec. 18 for all treatments
except the highest concentration of Cycocel. This treatment resulted in
a slight delay.
Eleven applications of gibberellic acid were made on the Chimes -
variety between Sept. 19 to Nov. 1. By the latter date there was con-
siderable show of flower color. Since the gibberellic acid damaged open
flowers, the treatment was discontinued. As noted, maximum flowering
occurred l2 months later, although some plants were ready for sale by
Thanksgiving. The plants that were treated with B-nine flowered earlier
than those getting the other treatments. It was estimated that each plant
received 33 milligrams of gibberellic acid.
(2) Use of gibberellic acid hastened flowering of all varieties given
approximately 4 weeks refrigerated storage beginning on Sept. 12. The
speed-up varied with the varieties. The Coral Bell and Red Wing varieties
were approximately 2 weeks early in flowering, whereas Chimes was about
4 weeks.
Storage period and flowerin_. The length and time of storage greatly
influenced flowering time. Approximately 4 weeks of storage begun in
October (Oct. 14 to Nov. 12) was as effective as the longer period started
in September (Sept. 12 to Nov. 123. The Oct. 14 to Nov. 12 period was
more effective .than the Sept. 14 - Oct. 14 storage period. It is possible
that the flower buds were not mature and ready for storage on Sept. 12.
Influence of retardants on forcin time. The influence of retardants
on forcing time varied with variety. Both retardants delayed the flowering
of Chimes and Hexe, but did not seem to influence flowering time of Coral
Bell. The flowering of Red Wing seemed to be hastened. The time and
duration of storage did not influence these results.
Vegetative growh dri'g forin. In general, use of retardants re-
sulted in less vegetative growth during forcing. However, there was
considerable vegetative growth on all treated plants.
AEALA LIGHT INTENSITY AND RETARDANTS:
- A study of the influence of light intensity on effectiveness of
B-nine and Cycocel was made at Auburn, using the azalea varieties
California Sunset, Dr. Bergman, Lentengroot, Pink Supreme, and Sweetheart
Supreme. Light intensities studied were full sunlight and 50% reduction
with saran cloth.
Light conditions alone influenced rapidity of flowering after re-
frigerated storage (8 weeks at 400 F). Full sunlight during the entire
summer, or full sunlight early in the summer followed by shade from
August 1, resulted in delayed flowering.
.4-
The effective concentration of Cycocel or B-nine was not 
influenced
by light intensity treatments.
WOODY OlRNAK[ENTALS PRODUCTION IN CONTAINERS
F ctors T ~4enc Co H Irnriness:_
The influence of soil mixture and soil moisture content were studied,
using plants of llupt i g- and A a The plants were
grown in No. 10 food cans and had been planted the spring before and grown
outdoors in full sunlight. During the printer, the plants were subjected
to 0 to 50 F. in a deep freeze, then placed in 
a greenhouse to determine
the extent-of cold damage. The soil-mixtures 
studied were: peat and -
perlite (1-1); peat and loam soil (1-i); 
and peat and builders sand (1-1).
When soil freezes there are three distinct stages. During the first
stage, the soil temperature decreases to approximately 
320 F. The next
stage is the freezing of soil moisture. During Stage 2 the soil-temperature
remains at approximately 3O-32? F. After all moisture is frozen, the soil
temperature again begins to decrease (Stage 3).. The lower limit is deter
mined by the air temperature surrounding the container of soil.
The soil temperature decreased much faster on the edge of the soil ball
than.1 inch from edge. During Stage 1, temperature decreased fastest at
both locations in peat and perlite medium; the soil and peat mixture lost
heat the slowest when the temperature approached'330 F. at edge of soil ball
of the peat and perlite mixture, recorded temperatures were as follows:
Temp. at Temp. 1 inch
Soil Mixture Edge of ball from edge
OF*{
Peatperlite-(lml) ........ 0 33.6 
38o9
Peat~sand (I=1) ... ,...,... 37.1 41.2
Peat.-soil (1--1) ....... ... 39.1 42.7
The length of time before Stage 2 was completed varied with location
and soil mixture.. This stage of the peat and perlite mixture was shortest
and that of the soil and peat mixture was longest.
ime requied orsoil'ir ueto fee
Soil Mixture Edge of ball 1 inch from edge
-5--
The rate of thawing was not influenced by the soil mixture, and it was
more rapid at the edge than 1 inch from the edge of the soil ball.
Injury to the plants was greatest in the soil and peat medium and
least in the perlite and peat medium. Abelia plants were injured more
than Ligustrum plants. On a score of 0 to 5 with 5 being no injury,
the following results were obtained.
S ofj1Iiixture
peat saerl4l)
peat-sand (ii) -p
Peat-soil (l--1) , .... . +
3.5
re p~s2.O
Dry soil cooled faster than moist soil at the edge of the ball
there was no difference 1inch from the edge. The time necessary 
t<
complete Stage 2, however, was longer with moist soil. Moisture cox
did not influence the degree of injury under the conditions of this
experiment.
, but
ntent
Ijoat u'nawId es:
The use of an illumination' totalizer to determine need for 
irrigation
of container plants was studied, using Burford Chi.nese Holly, Abeli.a
grandiflora, and India Privet. The plants were grown outdoors in full
sunlight in a soil mixture of I sand, i peat.
The instrument proved to be an excellent
for irrigation. Plant groit~h was excellent.
were as follows:
z rriio 
Cnto India
Prie
Check-visual means .. ...... 230
Light measure ......... .... 232
Light measure with rain
correction . ... .. ,.,..., .. .. 211
way of determining need
Growjth index of the plants
Abefla
~ndif1o&
105
100
I
3
uford
Holl
25
27
22
Making a correction for rainfall was not necessary, probably be-
cause rainfall-was not heavy. From April through October (the duration
of this study), only in 10 days (24 hr. periods) was rainfall of 2 inch
or more recorded.
Water was applied more times to the plants under the light control
than the check plants. This occurred primarily in the early part of
experiment.
2.3
1.2
0.5
to6 ..
Locon , Chee~k Ligh-t me _e gh ur wt
April .,..... 6 9
May *....I 15 
15
June ....... 11 l1 17
July ........ 13 15 
13
August....... 13 13 
13
September ... 12 12 12
October ....
J,,,,,. .
._.._
Total ...... 78 94 90
v 1 t on of b it r o its:
Use of the electrical conductivity test to determine viability of
plants and extent of damage from environmental conditions was studied
with rose and shrub althea as test plants. Stem sections were leached in
water and conductance of the resulting solution measured. The results
indicate that this procedure wi11 evaluate the extent of injury to plant
tissue.
Since data of' this test are expressed as a percentage of 2 readings
on the same tissue, the sample size did not influence the results.
Nature of the leached solutes was not determined, but some ninhydrin
sensitive compounds were present. Proline was the only amino acid
definitely identified.
Extraction acid determination of free amino acids was not a good
measure of viability of plants.
PROPAGATION
Softwood cuttings of'Eynon rva ir ~ cs Anthony Waterer Spirea,
and R.oasawchuri na were taken at weekly intervals from late March to
late April. After 4 weeks under mist, little difference was found in
rooting response. The cuttings increased in hardiness during this period
as shown by a shear test.
C em ,, re met:
-7-
DavLenth:
Increasing davlength in the spring resulted in increased rooting of
softwood cuttings of Pearlbush and decreased rooting of Camellia sanqua
and Roundleaf Japanese Holly. Da ylength did not influence rooting of
Forsvthia viridissima. There did not seem to be an interaction of daylength
and chemical treatment on rooting.
Nurse-seed Craftiny:
A procedure of inserting a scion into a germinating seed of chestnut
and camellia has been developed by Professor J. C. Moore, Department of
Horticulture, Auburn. The plant is removed, detaching the cotyledons.
The scion is then inserted into the remaining seed. Although the cotyledons
first initiate roots, rooting of the scion is stimulated. Professor Moore
has shown that a water extract of the cotyledons stimulated rooting of
willow, camellias, geranium and chrysanthemum cuttings.
The active chemicals may be extracted from the cotyledons with water
and many organic solvents such as methanol and ethanol. Using the mung
bean bioassay, the extract was shown to stimulate rooting.
Treatmnt No. roots per cuttina
Distilled water ............ 6.6
5 x - MIAA ............ 3.0
5 x 10 - M 
IAA+
extract from chestnut ...... 10.3
Apparently there are at least 4 compounds present in the germinating
chestnut seed that stimulates rooting as co-factors. Chromatographic-
analrsis showed the compounds to have a similar Rf position to the co-factors
isolated from Ivy leaf by Hess.
Influence of Leaves:
Chemical treatments with Hormodin, Chloromone, Rainbow, or RBotone
rooting compounds did not replace the influence of the presence of leaves
on the rooting of chrysanthemum cuttings. Use of Chloromone increased
the rooting response of the leafless cuttings. However, this response was
approximately one-half that of the check treatments; the other chemicals
did not have any influence on rooting of leafless cuttings. These results
show that compounds other than auxins must be present to induce rooting
and that the leaf is the center of production. Furthermore, apparentlr
some of these compounds are present in Chloromone.