TRESEARCH PESULTS 
FOR NTSEPTTEN
Horticulture 
Series, No. 
2-1
AGRIi *ULT U IL 
MTE1RITLNT 
STATION
AUB1JRN INTVERSITY
R. D Rouse, 
Director
M 174Alb u r~i9,4k 
1A la
M fir" 9 1 - 7 ?
CONTENTS
Page
Effect of Several Retardants on the Growth and Flowering of
Forsythia intermedia Zabel ................. . 1
Green Control of Weeds and Ornamental Growth ......... . . . 4
Effect of PBA on the Branching of Azalea cv. Kingfisher, Dwarf
Burford: Holly and Japanese Holly ...... ................ 5
Use of Municipal Compost as a Micronutrient Additive on
Forsythia intermedia Zabel ................ .
.. 7
Comparison of Various Dry Fertilizers on the Growth of
Flowering Azaleas ........................... 9
Use of Various Herbicide Mulches for Weed Control in Container
Ornamentals .................................... 
. . 11
Effect of Several Retardants on the Crowth and Flowering
of Forsythia intermedia Zabel
Kenneth C. Sanderson
Nature of work. Effects of 9 growth retardants, 5 applied as
drenches in 1 experiment and 8 applied as sprays in another experi-
ment, were studied on Forsythia intermedia Zabel.
Results and Discussion. Plants drenched with 23 ppm ancymidol had
reduced height 5 weeks after treatment, dark green foliage which was
retained late into winter, and delayed spring flowers (Table 1). After
11 months only ancymidol drenched plants differed in plant height from
untreated plants. Sprays of NIA -10637 at 1,000 and 6,000 ppm yielded
the shortest plants after 5 weeks. Severe distortion of leaves occurred
on BAY -102613 and NIA -10637 treated plants. Very few flowers were
observed on Nia -10637 sprayed plants. Ancymidol, ethephon, BAY -102613
and NIA -10637 sprays delayed flowering. After 11 months all sprayed
plants had similar heights and resumed normal growth except plants
receiving 6,000 ppm NIA -10637.
This research on forsythia shows that ancymidol can be a safe,
effective and persistant retardant on a rapidly growing woody species and
that BAY -102613 and NIA -10637, in addition to retardation, cause severe
morphogenic effects on forsythia.
Publication. Sanderson, K. C. 1973. Screening chemicals for controlling
growth and flowering of osythia intermedia Za4bel. 
Tor-:,cienc %2 477- 4I79.
Table -n t Plt a n a-1 ce n owrigIRe s t$-, o
PA&c Zabei After Cate Oni-
Chem'..ical Rate
T bight
Plant
Ecpearance
Floweri- 
g
Drench mg par
dxperiment 2.5tZ can
Ch 61e c k
ai,-cyc 3.opropy1-ca-(4.-methioxypheny7l) -5-
pyrim Idineinethanol
2 ,4-di ch lorobenzyl-t rib utyiphosphonium
chloride
(2- chic roethy-l) trinethylaramonium
chloride
M-orton confidential chemical
M"orton confidential ch-emical
Check
Ancymidol
BBP
am .. - 49,o8Za 79.3 
a
3-
63
%hormequat 2,951
EP-426-
EP-374
I
experiment pDm
Check 
11?6
Check
2-chlorofluorenecarbonicacid- (9) -methyl.-
ester
Succinic acid-2 ,2-dimethylhydrazide
a-cyclopro-Dropyl--( 4-meth.1oxyphenyl) -
5-pyriiidinemethanol
(2-chloroethyl) phosphoni c acid
Ethyl hydrogen 1-p ropy lphos phonate
B3AY -102613
SAD
Acyrnlidol
Ethephon
NiIA-106 37
19.1 c 59.3'b
42.7 b 70.1 ab
49.0 a 81.5 a
40.n o0 b .82.0 a
4.3.*4 b 77 .8 a
40.2 aZ 73.5 a
10 31.1 ab 75.5 a
50 26.0 bc 87.8 a
2,500
125
250
1,000
1, 000
38.6 a 91.8 a
34.4 ab 84.6 a
36.7 a 89.8 a
34.1 ab 79.6 a
17.6 cd 75.3 a
No rw. .al
Some bran~t?ing,
leaws dark
Nori
Noral
Considerable
branching_-of
c~1or, distorted
~o.~
Normal
N-ormal
Noral
Normal.
NTorma
Tormal
Branching leaves,
off-color, distortedl
F4ormal Normal
Some branching
2
leaves dark green Delaysall
Some branchin-g,
leaves dark green 56Thlayed
Normal Normal
Severe witches-.- 
Delayed.,-~'
broom-. leaiy,-s
di tr~ki Hlied -k
hem Ic
1, . A r.2./s+
Table 2. (Cunt' d. )
Chemical '?.at e
Height
5 wk. 11 mo.
Plant
appear:nce
Spr ay
experiment
Ethyl hydrogen l-propylphosphonate TTA-lO637 6G,000 
1.5,2 d 3 3.0 b Severe wtchc elyd
b roomlavsflwr
distorted kle
Tlepan separation for experiment 
in columns, by Duincan's 
multiple range-test, 5% 
level.
Chemical
Flowering
response
:ew
Green Control of Weeds and Ornamental Growth
Kenneth C. Sanderson
Nature of Work. The green control method will rely on new and better
chemicals. The new type chemicals will retard and disrupt the growth of
weeds instead of killing them. These chemicals may also control the size
and shape of desirable landscape plants with little or no injurious effects.
Potential chemicals for green control have been evaluated in greenhouse
and field studies. Morningglory, radish and silktree seedlings, 4 cm high,
were sprayed with 500 ppm Maintain CF 125, 500 ppm Maintain CF 125 plus
31,619 ppm NH-30, 31,619 ppm PM-30, 500 ppm Niagara 10637, 500 ppm Niagara
10656, 400 ppm ancymidol, 400 ppm ancymidol plus 1,000 ppm 
CEPA, and 5,000
ppm DPX 1840 in a greenhouse experiment. In April of 1971 and May of 1972,
kudzu was sprayed with 1,000 ppm Maintain CF 125, 1,000 ppm Maintain CF
125 plus 3,077 ppm H1-30, 3,077 ppm NH-30, 2,000 ppm CEPA, 6,000 ppm Niagara
10637, 9,000 Niagara 10637, 4,800 ppm DPX 1840 and 9,600 ppm 
DPX 1840
in field experiments.
Results. Silktree was damaged by all sprays except Niagara 10656 
and
DPX 1840. Ancymidol, Maintain CF 125, Maintain CF 125 plus 'H-30, 
and ancy-
midol plus CEPA damaged radish and morningglory. Maintain 
CF 125 alone, or in
combination with NH-30, or CEPA, controlled kidzu growth 
for 6-8 weeks.
Publication. Sanderson, K. C. 1973. Green Control on the 
Way - To
Control ',eeds, Regulate Ornamental Growth. Highlights 
of Agr. Res. Agr. Exp.
Sta. Auburn Uiv. 20(2) 10.
r ,ffect of PBA on the Branching of Azalea cv. Kingfisher,
Dwarf Burfordi Holly and Japanese Holly
Kenneth C. Sanderson and Willis C. Martin, Jr.
Nature of Work. PBA (Shell Ghemical Company's synthetic cytokinin 
SD
8339) has been reported to influence branching in some plants. The purpose
of this work was to test 1BA for branching effects on azalea cv. Kingfisher,
dwarf Burfordi holly and Japanese holly. Recently established liners were
sprayed with 0 ppm, 200 ppm, 400 ppm, 800 ppm, and 1,200 ppm PBA. Dupont's
surfactant B 955 was added (4 mhZP.) to all sprays. Treatments were applied
to plants until runoff on Feb. 21, 1973 and 2 weeks later, all plants were
sheared. The azaleas, Burfordi hollies and Japanese hollies were grown in
a lightly shaded, (5,000 ft-c maximum) fiberglass* polyethylene, and glass
greenhouses, respectively. Norual cultural practices for container plant pro-
duction were used on all plants. Total number of shoots per plant were
determined on August 9, 1973.
Results and Discussion. Branching in Japanese holly was consistently
increased by PRA spray concentration up to 800 ppm (Table 2). Sprays of
1,200 ppm PBA caused a reduction in shoot number, very short shoots and a
witches-broom effect on the' plants. Azalea responded erratically to PBA
sprays. Sprays of 200 ppm and 800 ppm increased shoot number in azalea,
whereas concentration of 400 ppm and 1,200 ppm PBA reduced shoot nlumrber.
With.Burfordi holly, all sprays increased branching except 800 ppm which
reduced shoot number. PBA shows mich pror-mise as a chemical for reig
6
Table 2. Effect of "FBA Sprays on Total 'ITuaber of S7hoots
'Per Plant of Three Woody Ornamentais
z
PBA concentration Number of shoots 
per .plant
Azalea Burforci Japanese.
_______________________________________olY Holly
ChkS~be ck . . 0 0 0 0 0 0 0
200 ppm .. . . 0 0 0 ** *
400ppm...........
800 ppm........
1,200 ppm.................
s 15 .1
0 17.7
* 12.3
* 15.3
14 .3
4.4.56.3
4.6 67.6
4.8 92.7
3.7 101.9
4.8 95.3
Z
Means for 7 -azaleas cv. Kingfisher, 40 Burfordi 
hollies and 10 Japanese
hollies, respectively.
Publications None
Use of unicipal Compost as a Micronutrient 
Additive
on Forsythia intermedia Zabel.
Kenneth C. Sanderson and Willis 
C. artin, Jr.
Nature of Work. Research 
at Auburn has revealed that 
municipal compost
contains Cu, in, Fe, Zn, 
and No, therefore municipal 
compost might be used
as a micronutrient 
source. Two municipal 
composts, Alive (a quick, 
digester
over, compost produced 
by Lone Star Organics 
Co., Houston, Texas) 
and Mobile-
Aid (a slow, windrow method, 
compost produced by the 
City of Mobile, Alabama),
were compared with 
the micronutrient 
sources listed in 
Table 3. Established
liners of Forsythia 
intermedia Zabel grown 
in 2.51 cans containing 
111
(v/v/v) soil, peat, and perlite, 
received micronutrient treatment 
on August
19, 1970. No attempt 
was made to balance 
elements or amounts 
of elements
applied. Standard 
cultural methods 
for field grown 
containers were 
used.
Flowering and plant condition 
was observed 8 months after 
treatment and plant
.height was recorded 1 year 
after treatment.
'Results and Discussion. 
Most plants flowered 
normally and did 
not exhibit
any phytotoxicities. 
Plants receiving 
FTE, Mobile-Aid 
or Rayplex mixture
were delayed' in flowering 
in some replications. 
Treatment with Green-Garde
micronized iron 
resulted in .the tallest 
plants, however 
S.T.E.M. treated
plants were just 3.3-cm 
shorter than Green 
.Garde plants. Rayplex 
mixture
..plants yielded the shortest plants, followed by Mobile-Aid and Alive compost
plants. These results 
may indicate a response 
to iron since Green 
Garde
micronized iron, 
STEM and iron chelate 
supply considerable 
iron. Also, pre-
vious work at Auburn 
revealed Mobile-Aid 
to have low available 
iron and a
high pH. The application 
of 240 ml of municipal 
compost may have influence
soil aeration in addition 
to nutrient and pH 
effects.
Table 3. Ef fect of Various Micronutrient Additives on the Height of Forsythia ItrndaZbl
Additive Element Analysis (% Rate Hih
B Cu Fe Yn I.0 Zn (ml/ 2.e5ti)()
Alive Comipost. .......
Fritted Trace Elemen-rts No. 50 4
Green Garde MiU*cronized Iron..
Iron Chelate !Mo. 330 ..
Mob ile Ai d Comp os t....
Rayplex Granular Mixture...
Soluble Trace Element Mixture.
Ce k0.a.a.0...........
Trace
3.80
0.005
4.64
0
0007
7.00
0.05
0. 76
3.20
0
1.03
14.00
10.0
0.51
3,84
7.50
0
?0.06
700
32.
0.05
1.74
8.15
0
0.001
0.907
0.23
7.00
0.10
- 3.15
0.046 4.50
0 0
240.0
1.2
408
150 (0o.29/t)
240 .0
1.2
150,0(0. 89g/e)
Publications : None.
00
69.1
72.6
81.6
72.o3
66.0
58.4
7003
70.4
Comparison of Various Dry Fertilizers on the
Growth of Flowering Azaleas
Kenneth C. Sanderson and Willis C. artin, Jr.
Nature of Work. Red American Beauty and Chimes azalea plants growing in
12.5 cm pots were shifted to 15 cm pots using sphagnum peat moss as a trans-
planting material. The medium was amended with 56 g of dolomitic limestone
and 56 g of gypsum per bushel. Fertilizer treatments were added as shown
in Table 4. Plants were grown in an evaporative cooled greenhouse from July
14 to November 10. From November 10 to December 15 the plants were stored
in a lighted refrigerator at 450 F. Following storage, the plants were
placed in a 600 F. MNT greenhouse for flowering. Dry weight was obtained
at flowering on 5 Red American Beauty plants and 3 Chimes plants in each
fertilizer treatment.
Results and Discussion. Flowering occurred on January 31 for Red
American Beauty plants and on February 16 for Chimes plants. Fertilizer treat-
ments did not seem to influence the time of flowering. Sulfur-coated urea
and Osmocote 18-6-12 produced the heaviest plants for the two cultivars
(Table 4). A mixture of Osmocote 18-6-12 and Osmocote 14-14-14 was the third
best treatment for Chimes plants whereas untreated Red American Beauty plants
ranked third best. When the dry weights of the cultivars were averaged the
3 best treatments (in order) were sulfur coated urea, Osmocote 18-6-12 and
lfag-Arp.
Table 4, Dry Weight (g) of Chimes and Red American Beauty
Azaleas Grown on Various Fertilizer Regimes
Fertilizer treatment Cuitivars Mean
Chimes Red American
Beauty
Check.... . .o.235.4 218.7 22711
12g Agriform tablet ..... . 266.2 174.5-220.4
Sta-Green 12-6-6, 1.98g/bu......255.2 155.0 205.1
Sulfur-coated urea 38-0-0, 66g/bu . 284.4 274.3 279.4
Nitroform urea 38-0-0, 66gfbu... 230.2 176,*7 204.5
Mag-Amp 6-44-~7, 254g/bu, .. .253.2 228.3 240,8
Osmocote 18-6-12, 205g/bu.......301.6 249.2 275.5
Osmocote, 14-14-14, 264g/bu. . . 264.4 191.7 228.1
Osmocote mixture 18-6-12, 153g/bu, a 283.4 160.0 221.7
8-8-8 254g/bu.... ... . 24 7.8 201.3 224.6
ean.. .. ...... 2.23
262. 20 3.
11
Use of Various Herbicides Mulches for Weed Control
in Container-Grown Ornamentals
Kenneth C. Sanderson and Willis C. Martin, Jr.
Nature of Work. Processed municipal compost and sawdust were 
combined
TM 
TM
with dichobenil (Carsoron , Thompson Hayward) or UC 22463 (Sirmate 
, United
Carbide) and used as mulches on Pfitzer Juniper, 
Shore Juniper, and Pitto-
sporum (Table 5). Plants (liners) were established 
in 2.51 containers on
May 15 using a steam pasteurized medium of (1:1:1, v/v/v) 
soil, peat and per-
lite. On August 1, mulch treatments were applied 
to the soil surface of each
container to a depth of 2.5 cm. A sheet of tar 
paper was placed under the
containers at the beginning of the experiment to control 
weeds between the
containers; however weeds were allowed to grow in the walks on the edge 
of
the paper. Natural weed infestation occurred 
from the weeds growing in the
walks and surrounding areas. Normal container 
production practices for field
grown plants were followed. A randomized 
block design consisting of 5 plants
per treatment and 4 replications was used with each species. 
On November 20,
the containers were rated for the number 
of weeds per container as follows:
0 = no weeds, 1i = 1-3 weeds, 2 = 4-6 weeds, 3 = 7-9 weeds, 4 = 10 
or more.
Results and Discussion. No phytotoxic injury was 
observed on any of the
plants treated with dichlobenil or Sirmate mulches. Natural 
weed infestation
was not a serious problem in this experiment; therefore 
weed control benefits
were not great. Generally sawdust plus Sirmate, sawdust, 
municipal c;mpost
plus Sirmate gave the best weed control (Table 5). 
With Pfitzer Juniper plants,
mulches of sawdust plus Sirmate reduced the weed control rating by 
more than
50 percent over the no mulch treatment, Sawdust mulch provided the best 
weed
control on Shore Juniper plants. Pittosporum containers had the 
fewest weeds
when mulched with sawdust plus dichlobenil.
12
Table 5. W,,eed Control 'Rating of Various Mulch Treatments
Applied to Three Container Ornamentals
Mulch treatmentWeed control ratinfC
(2.5 cma depth)
Pfitzer Shore Pittosporum Mean
Juniper Juniper
Chec k.......... 11 1.111.9 1.4
Municipal Copost ......... 7 1.3 1.5 12
Municipal Compost, plus dichiobenil
114g/6 cu. ft.*00. ......
1.0 0.9 1.6 
1.1
Municipal Compost, pluis Sirmate
114g/Gcu. ft...........0.8 0.9 1.2 100
Sawdust , . . ..... ... 0 ,009 0.7 1e4 1.0
Sawdust plus dichlobenil
114g/6 cu. ft................., 0.9 1.3 0.7 1.3
Sawdust plus Sirmate
114g/6 cu. ft,............0.5 0.9 1.3 0.9
Weed control rating (means for 20 plants per species)
weeds per container, 2 Ow 4-6 weeds, 3 =7-~9 weeds 
, 4=
0 = no weeds, 1I-- 1-3
10 or more.
?ublications: None