THE PROPAGATION OF THE
HSGHBUSH BLUEBERRY

THESIS FOR THE DEGREE OF M. 8.

Stanley Johnston
1930

   

_ .v I ‘<‘ 7‘: ‘. '- . ‘ I . . . ..1

-—--._J.. - “-A.A---___-‘..J.‘
\

. l. ' *‘ ’ 3 ,
'8' . .'..' :.' 'JM "‘M"'. ‘TAYE I:‘J|.‘_l- 'v vnliw’Jifl
' '. i . I ' ‘ ‘ ‘ 3 1 ‘ ‘
‘ - J ’ I ‘ ‘3 l ;‘ 1' l
3 -fi,‘ ‘ ‘x ‘ ‘I
. " 1 \ ‘ ‘
.' ‘ ‘IJ ‘ H ‘ \
* 3 ‘- . ‘ \ . ‘\ l: \ 1 ‘
J \ 5 3 ; ‘
( ¢ ‘.‘ V.
I. y “ ‘I'.‘
I I ‘
I

3 1293 00585 0312

H, v---_‘*——~ _.__
, . ‘ , _‘

  
      
       
     
  

 

 

 

"2..- 9. "’

. 'i u _ , ‘y.':o." _ f ‘l" 1.
. .. ?" '3“qu w" 4“. - 1,, ' .
.| sl"‘ ;| N‘g‘x':\;f$.; -“5 ‘0" “ ..v" ‘
4‘ {5,} \. k ‘ ~._- 1 2. ( {arrafmdfi “(iv—3'
' I

‘ s D J) . I ‘ . y ‘. 'i“ ‘ l .. q ’
1“ . y“3‘ ' A ‘4 .‘I ‘ - {f}. ). }‘-‘.: . ;~~‘ " .
.' . I “~ .t“

i : O

‘ _ s I.

-‘ 51 1:1‘2.‘

- 2.17 1‘; .
. . .

 
 

c Q .. V. ‘.
“51.2 .‘.'\- " r‘ofi‘. .‘T"‘:‘.¥.‘"
aswft 5.;

w 4‘;
I

    
   
 

0' I I' .‘ . L m. '

W ‘ {J'l "' h). "1‘." .' "'41; IX~.‘-‘!f.,' \.‘ '
(an: -,\£¥U {'{k' :Qz‘Nj'q‘k‘".\’:.,?-l ‘ .
. .--;,I$.41--,' x'; ' .W 515-...4‘5 ‘fl’c...’ .’ ;\
.s 5&5 .;. *11' a, %.; : g, '. ‘f ‘3“

      
     
      
  
   
   
   
       
    
    

 
  

‘é’x

cf.
-z}‘!‘l’
1“- ”'5‘
"Ay

I

  

I I.
3 m x- 3 x «M ‘7,
* Lflgfim. if“?! 33,-, 9:5;(9- m.
. l ‘ u ‘ \. ( .' 5 {"1 ...:‘A .
.';‘;‘bn3’f3}airei-¢ W» W a u

. ' ,.' . 3' . l

g x“1£.»‘h",r Q; ' fi :fi '4' )vu'y‘ "_ *
(1 914...“. 1")“ " -'.- - .. ' ya“? 1
;.( "“1 'a ,. ‘. -.5' ‘3. in 5‘ ., if V'Wil‘ 3 I

a
0 l

 
 

H._OJ"., “H! (In. -A
8%3‘1'44‘“ ' 5‘. :93" V“)

. ‘ y ‘5. I, ‘3,~"".:-": l...‘ . " I. - . .v 'v
3331?}; 3:33 5~-1‘,;~n;;;."-*1'5'3‘J»' .3 3
. \ a:‘.fi\{ .{tfi.fi“' ’0’ J o 4:5?"v,.” . f .. 1):?" ,..'_
-€Jt . u - - ~ 3* ‘. "3

L. J?-
v.1

. r: . -
,'§:".s',t:~~‘ I' '; ' ‘1
3 . \'
I

.3 m.

$117336V33 3 h
’ 3473-.7‘33. 3‘53‘6‘5 7

I I“.th‘§:s‘z ;?$'. Viva. ‘ .

" ‘k‘vfl' Ix, "
-. " “x! . .
WV?» 373’ ‘ .. .933“
. ' 4 $ ‘ ' '- '3 ‘K‘l” 'I" ' ‘ 'l ' .‘. ~ ‘ ~ . ' ‘I n ‘ ‘ I ' ' "'.:!‘"'¢“ I"' r b ‘
L" wt ‘ " ' ‘ l ‘ 1". 55‘“- . "‘ 'N 7,1” 3‘ d". f ‘ " .' l‘... 5 V .. . ' - I‘ -. . 15"? _. "~ ‘_ ~. 3";6'.§r;.".‘5.is._
V _ -r : 5 3 3 . 5- .v , 3.. _‘ ~‘.. :l '0.

:ML‘ ‘. , , : 1.; it”, .‘
.. '1‘} .5 3/1, ‘_

. -. ‘ . i 3 '.I 1". ‘7
~5. ' in" mff'!‘ ~ “$3.1“;-
cg» a”. .. :3 r,-
{' '9. "a- ,.""." 3‘ fi Mr; 5 ‘1’"?-

““I‘ ~. . ‘ .'-!_1“ fi:' .
. .’ ‘0 ‘v —-._. 4,
3 r‘-- -

,.

:1 I
'. 'd x"~|?’l.
‘. . D“. . ' s
u/i. ‘Me'l.’ Q \1 7'3. J?!" «“5 4:. .
Lu .-ffy‘1"f.':r’ I.“ ‘ ' ' “
‘ 2"; ~111-

3' .p‘ .
‘9; Mk;

1 5 “8‘. 'I' -"

'V

,3
.3

s
:3

. 3,

g“
k.

37; _

\' “ ‘.‘>"I &;~0‘0’§ _‘ .
‘07‘.’\‘ A '. ‘ c
.k‘":, ' J '

‘: J“ “'».:‘§“¥"’.‘:‘4 -‘ . I
x‘ l.‘\ l .. u. c A
3 _. .458}; ii! .3
-§T’*"”‘>‘H‘+‘v'tf-V £961. ,.
- a. J .3»
11W; '5' {If 5 "

u; .3.“ 72?.
~4~§§3rrf
.p-r; I J;‘

‘ _
x. ‘-
‘n‘v -
l

, '3‘
u y‘('
f

I
3.":
‘r

‘3

_-
~ I.

n
_ V-

33: at

I'.“
.- J
A.

K

. .r‘ ~‘ ‘
‘O.’ 4".”

‘l
#5“
J
l."

'. I, '. ' 0-
~ ,m.

V' ‘ hi;

I".
_‘\,o

'.‘

 

The Prepagation of the Highbush Blueberry

Thesis

Submitted to the Graduate Faculty of the Michigan
State College of Agriculture and Applied
Science in partial fulfillment
of the requirements for
the degree of Easter

of Science

by
Stanley Jonnston

’ 1930

 

THF‘QIS

 

 

 

-1-

The Propagationfof the Hignbush Blueberpy

V. Corymbosum

Stanley Johnston

The highbush blueberry, Vaccinium copymbosum, has
for many years been recognized as a native fruit of
great possibilities. Its introduction into cultivation
and its improvement have been retarded by three factors:
an adequate supply of berries from the wild area, lack
of knowledge concerning the plant's soil requirements,
and the difficulty of propagation. At present, however,
the crop from the wild areas does not supply the demand.
More accurate information concerning the soil require-
ments of the blueberry plant has been made available
through the investigations of Covillet Though consider-
able information has been published concerning methods
of propagation, the highbush blueberry is still considered
so difficult to propagate that the price of plants remains
too high to permit rapid development of a cultivated blue-
berry industry.

Review of Literature
he early investigators of blueberry prepagation

worked largely with seedlings and ex erienced considera-

ble difficulty in aerminating and growing them. Dawsonz

Q
of the Arnold Arboretum was one of the first to grow
seedlings successfully. He was successful also in layer-
ing shoots but does not report any investigations in root-

ing cuttings. At about the same time, Sargent, also of

1002.12 1.

the Arnold Arboretum, succeeded in growing seedlings.
Kunson5 reported in 1901 growing seedlings successfully
but does not mention work with cuttings. Card4 appar—
ently carried on the first ex cnsive studies in rooting
blueberry cuttings. His investigations ex ended from
1898 to 1905 inclusive. Hardwood cuttings were tried in
the greenhouse bench without success. Root cuttings

were tried in a greenhouse bench and also in trenches in
a garden. Root—grafts also were used. Sand and a come
bination of sand and moss were used as rooting media, the
latter provi 3 more satisfactory. In March, 1903, Card
concluded that root cuttings and root grafts offered
fairly successful means of propagation. In 1921, Coville5
described several methods used in prOpagating the highbush
blueberry without presenting data on the percentages of
rooting obtained with the different methods. Beckwith

and s. Coville6 reported in 1927 hat the difficulty in
propagating plants has held back the more rapid develOp-
ment of the blueberry industry. They gave general recom-
mendations on methods of handling hardwood cuttings. No
data were presented on any investigational work. Crowley7
in 1928 reported successful use of the ‘ubering method of
prepagation in the state of Washington, although no data
were given. Mowry and Camp8 in the same year gave general
directions for the handling of cuttings of the southern
blueberry, Iagoinium virgatum. Hildreth9 reported in 1929
that the lowbush blueberry could be rooted successfully by

rhizomes. No data were presented on investigations with

 

Fig.1.- The propagating frame in the center is the solar
frame, at the right is the box frame, and at the left the
open frame. Note the lower sash on the solar frame. This
must be opened on hot clear days. The box frame has one
board on hinges so that the frame can be ventilated on
extremely hot days.

in.

the highbush blueberry.
Various Methods of Propagating the Highbush

Blueberry,

 

Of all the methods described for prOpagating the
blueberry, the rooting of cuttings, either hardwood or
softwood, if feasible, is the most logical and economical
way of producing large numbers of plants without serious-
ly disturbing the parent plant. However, plants propa-
gated from cuttings have een available for the trade only
in a very limited quantity. Division has been tried and
is still used as a method of propagating the blueberry.

The old plants are dug and split into pieces, each piece
has a portion of stem and a few roots. A large portion of
the blueberry plants now sold by nur eries are either ob-
tained by division or are nursery-grown seedlings. Seed-
lings, hovever, are of limited value except in the guest
for new varieties, as they do not reproduce the original
variety. Budding and grafting are of little value, because
the bush sends forth a number of new shoots from the crown
each year. Though Card4 reported some success with root
cuttings, Coville5 had little success with them. He found
that most of the pieces that rooted were not true root
cuttings, but were really stem-base cuttings. Since the
root system of the blueberry is fine and very much branched,
he taking of root cuttings of sufficient size would result
in a very severe root pruning. Stumping requires cutting

down the plant, mounding the crown, and raoting the new

shoots as they push through the soil. Mound layering is
an attempt to root the old and new shoots at the base
without resorting to pruning as in stumping. Both of
these forms of layering are successful but they are slow
and result in the diversion of either all or part of the
plant from fruit bearing. Tubering, a method described
by Coville, requires old wood from one-quarter to an inch
or more in diameter. It is difficult to get a large
amount of such wood without heavily pruning the parent
plant. Due to the objections to other methods of propa-
gation, the data presented in this paper are largely on
investigations in rooting hardwood and softwood cuttings,
with the exception of some brief comments on attempts to
use root cuttings in the greenhouse and on germinating
and growing blueberry seedlings.
Investigations on RootinggCuttings in the Greenhouse
During the winter of 1926, and to a lesser extent in
1928 and 1929 rather extensive trials were made with dif-
ferent methods of rooting hardwood cuttings and root cut-
tings of the h'ghbush blueberry“< in the greenhouse. Though
the results were almost entirely negative, a brief outline
of the work is presented to show the scope of the investi—
gation.
A. Hardwood cuttings.
a. With bottom heat. House temperature 600 - 700?.
1. Ordinary 4 inch cuttings.
2. Heel cuttings.
3. Jallet cuttings.
*The plants used in these eXperiments were either V. corym-
bosum, or, in some instances, possible hybrids of that with

some other closely related species.

b. Without bottom heat.

three treatments as listed above under a.

se 23 for three days before planting.

2p " one week before planting.

Potassium pernanganate .01 mol. sol. 56 hrs.

before planting.

5. Boric acid .001 mol. sol. 36 hrs. before
planting.

6. Mono-potassium phosphate .002 mol. sol. 36 hrs.
before planting.

7. Phosphoric acid 2,cc in 1000 cc then to sucrose
2 48 hrs. before planting.

3m
9
g
(D

o
C
S
d

$Cfihfl4

,o
8. pH 3* solution for 5 days prior to planting.
9. n 4* n n fl fl n fl n
10. fl 5* n n h n n n n
11. n 6* n n n n n n n
12. n 7* '1 n n n n n n
13 . n 8* n n n n n n n

14. Half of the above mentioned cuttings in various
pH solutions were not planted but left contin—
uously in the solutions.

15. Carbon dioxide treatment of cuttings for one
week prior to planting.

0. Special treatments with peat extracts.

1. Cuttings left continuously in raw peat extract.
11 fl

2. " " bacteiized peat
extract. -

5. Cuttings in sand watered with raw peat extract.

4. " " " " " bacterized peat
extract.

3. Root cuttings.

a. With bottom heat. House temperature 60 to 70°F.
1. Root cuttings scarified in various ways.
2. " " split at the butts.
3. Without treatment.
b. Without bottom heat
1. Above treatments repeated
c. Same chemical t~eatments as with Lardwood cuttings.

C. Tubering

a. With bottom heat. House temperature 600 to 700?.
1. Two and three-year wood placed horizontally and
covered with about an inch of soil.
2. Cuttings of one-year wood treated as under 1.
0. Without bottom heat.
1. Repeated as under a.

*These solutions were tap water to which was added enougr
dilute sodium hydroxide or hydrochloric acid daily to
maintain the desired reaction.

 

 

 

 

 

 

 

Fig. 2.- A general view of part of the propagating frames
used for mating blueberry cuttings at the South Haven
Experiment Station.

-5-

The cuttings used in the greenhouse experiments in

1926 were taken from wild plants of V. corymbosum, which

 

in subsequent years produced a high percentage of rooting
in solar frames. There is nothing to indicate that cut-
tings taken from wild plants, barring slight individual
differences, are more difficult to root than cuttings taken
from the cultivated varieties. Fifty cuttings were used
in each treatment; they were kept in muSlin shade and wa-
tered when necessary. The rooting medium.was a mixture of
half sand and half American peat. No significant differ—
ences could be noticed in 1926 as a result of any of the
treatments.

Later investigations with various types of propagat—
in; frames out-of-doors showed that German peat was a
very satisfactory rooting medium. Accordingly, in the
winter of 1928, seventy-five cuttings were placed in a
greenhouse bench with German peat as the rooting medium.
Twelve per cent of these cuttings rooted, which was a
higher percentage than had been obtained by any of the
treatments in 1926.

It is possible that the season at which the cuttings
Jere taken and set in the prOpagating benches was respon—
sible for the unsatisfactory results obtained in the
greenhouse emperiments, but it is also possible that the
answer to the question might rest in the methods used.
at any rate, the question cannot be answered with the data

available.

-7-

Investigations With Diffs ent Types of

atin; Frames in the Open

The cuttings used in the various investigations with
different types of prOpagating fr aes out of doors at
South haven were all taken from plants of the improved
varieties, including Rubel, Pioneer, Cabot, and Adams.
The hardwood cuttings a re taken during the first Week of
April and ‘he softwood cuttings were taken early in July,
the exact date depending upon the season. German peat
was the rooting medium used. All of the frames received,
as nearly as possible, the same care.

The cold frame has been used for many years for
rooting cuttings of different kinds of trees and shrubs.
Several investigators and prepagators have used it in
atin; the blueberry. In these investigations the
cold frame was used for five years with unsatisfactory
results. The percentage of rooted hardwood cuttings

varied from 5 to 15, dependint upon the rooting medium

I. to
‘0 .

used and the season. Less than one per cent of softwood
cuttings were rooted in the cold frame.

The solar frame (Fin. 1) was developed by U. S.
Department of Agriculture investigators, for rooting

cuttings of citrus and other subtropical plants. It was

"lj

p‘obably used first for blueberry cuttings, by . V.
Coville and 3. May, Jr. It has also bee: used to some
xtent by Joseph White & Company of fihitestg, New Jersey.

In these investigations, the solar frame was first used

in 1927, with good results. In 1923 and 1929, this type

 

Fig. 3.- Softwood cuttings rooted in American peat,
German peat, and sand. The two at the left were rooted
in American peat; the two in the center in German peat,
and the two at the tight in sand.

7a,

was used much more extensively and hi;; percen—

g-)
1)

tages of rooted cuttings were obtained.

The solar frame operates on the principle of receiv-
ing bottom heat from sunlight. Of course the heat varies
in its intensity and amount. On clear, hot days it is
necessary to Open the lower sash to avoid excessively high
temperature in the cutting bed. 'This frame allows very
good aeration of the rooting medium.

The box ‘rame (Fig. l), as far as is know, is an
original type of frame which was first constructed to test
the value of the bottom heat derived from sunlight by the
solar frame. It was found that this type of frame gave
excellent results in propagating both hardwood and softwood
cuttings. The box frame has two important advantages over
the solar franm; first, it does not require as constant
attention on hot days; second, it is about SO per cent
cheaper in construction.

The box frames used in these experiments were six feet
in length, 27 inches in width, and 40 inches in he ght.
However, these dimensions are not arbitrary, they can be
changed to accommodate glass sash of various sizes that may
be on hand. Storm windows can be used on blueberry frmnes
during the summer. The 40 inch height is a convenient one
for takinj care of the cuttings without too much stOOping.
Eight inch spruce lumber has proved to be a very satisfac—
tory building material. 2 X 2 pieces are used for the
corners. One board in front is left on hinfes to provide

for ventilation on unusually hot days. The cutting tray

to was used much more extensively and high percen—

r.)
4.,
U

0
*‘b
H.)
*‘2’:
p'x
( L
ya

rooted cuttings were obtained.

CT
S5
( D
U)
H.»

o
The solar frame operates on the principle of receiv-
ing bottom heat from sunlight. Of course the heat varies
in its intensity and amount. On clear, hot days it is
necessary to Open the lower sash to avoid excessively high
tenmerature in the cutting bed. ”This frame allows very
good aeration of the rooting medium.

The box frame (Fig. l), as far as is know, is an
original type of frame which was first constructed to test
the value of the bottom heat derived from sunlight by the
solar frame. It was found that this type of frame gave
excellent results in prepagating both hardwood and softwood
cuttings. The box frame has two important advantages over
the solar frame; first, it does not require as constant
attention on hot days; second, it is about SO per cent
cheaper in construction.

The box frames used in these experiments were six feet
in length, 27 inches in width, and 4O inches in height.
However, these dimensions are not arbitrary, they can be
changed to accommodate glass sash of various sizes that may
be on hand. Storm windows can be used on blueberry frmnes
during the summer. The 40 inch height is a convenient one
for taking care of the cuttings without too much stOOping.
Eight inch spruce lumber has proved to be a very satisfac-
tory building material. 2 x 2 pieces are used for the
corners. One board in front is left on hinges to provide

for ventilation on unusually hot days. The cutting tray

is made of four-inch spruce lumber with ei.hth-inch
hardware cloth stapled on the under side. The hardware
cloth has been superior to wooden bottoms. The cutting
tray rests on braces nailed on the inside of the frame
eight inches below Mh tep. The cutting tray can be
removed so that the same frame can be used for both
hardwood and softwood cuttings. The small space between
the end of the cutting tray and the frame can be filled
with pieces of burlap or paper while the frame is in use.
The inside of the box belOJ the cuttin3 tray is lined with
tar paper which prevents excess ventilation tb rou h the
crae he and helps to maintain a more uniform temperature.
After the cuttings are planted, the glass sash and shade
are placed on top,as shown in Fig. 2. Details of box
frame construction are shown in Figure 10.

The open frame (Fin. 1) was constructed in an effort
to find a satisfactory propa gatin3 frame even simpler and
less eXpensive than the box frame. It has been used only
one year, Although the results obtained with it were much
better than those with the cold frame, it did not prove as
satisfactory as t: 1e box or solar frames.

Table 1 shows the results obtained in rootin; hard-
wood cu ttin3s of Pioneer and Cabot in the several types of

frames.

“3

rnable 1. Rooting hardwood cuttin3s in di
JLI

fe rent types
of frames. (1929) (Gennan peat used as o

1~ r oting

p.14

 

 

 

 

median) f j A
Pioneer Cabot
TNumber Per cent Number Per cent
cuttin3spfipooted cuttings rooted
Cold frame 20 25 20 20
Solar frame 59 89.8 45 84.4
Box frame 119 89.9 70 78.5

Open frame 112 69.6 72 70.8

 

Fig. 4.- The blueberry shoot at the left shows
winter injury, while beside it is another shoot
showing the extent of the injury. The shoot in
the center is undesirable for cuttings because of
prevalence of fruit buds. The shoot at the right
illustrates the best type of wood to use for hard-
wood cuttings. At the extreme right is a hardwood
cutting ready for planting.

42L

-10-

The data in Table 1 show that the cold frmne gave
the lowest percentages of rooted cuttings. The open
frame gave rather high percentages of rooted cuttings,
although not as high as the solar or box frames. The
cuttings also rooted much more slowly in the open frame.
Similar results were obtained in previous years with the
cold frame and the solar frame, and, in 1928, with the
box frame.

Table 2. Rooting softwood cuttings in different types
of prepagating frames (1929) (German Peat used as the
rooting medium)

Rubel Cabot Adams
Number ‘Per cent Number Per cent Number ‘Per cent
cuttings rooted cuttings, rooted cuttings rooted

 

061d frame 40 0 20 0 20 0
Solar frame 126 84.1 126 84.1 126 82.5
89x frame 120 85.0 120 85.5 120 81.6

 

The data presented in Table 2 show that softwood cuttings
of Rubel, Cabot, and Adams failed to root in the cold frame,
while very good results were obtained with softwood cuttings
of the same varieties in the solar and box frames.

Approximately 11,000 softwood cuttings and an equal
number of hardwood cuttings of Rubel, Adams, Cabot and Harding
were handled in box frames during the 1929 season with high
percentages of rooting. Equally satisfactory results were
obtained in 1928 with smaller numbers of cuttings. Pioneer,
which is probably the most difficult of all the cultivated
varieties to root from cuttings, gave high percentages of
rooted hardwood cuttings in both the box and solar frames
during the 1928 and 1929 seasons. Softwood cuttings of Pi—
oneer have given such variable results that it is considered
wise to concentrate on the use of hardwood cuttings of this

varietv.

-11-

Influence of Different Rooting
Media on Rooting Cuttings.

Send, peat, peat moss, and various combinations of
peat and sand were used as rooting media, with results

shown in Table 5.

Table 5.- Rootinghardwood cuttings in various materials (1929).

 

 

Rubel Cabot Adams
Per cent“* Per cent Per cent
No. pfirooted ,_No. rooted No. rooted
German Peat 40 87.5 20 70 20 60
American Peat 40 55.0 20 55 20 5
German Pest and
sand 40 72.5 20 45 20 30
Sand 40 57.5 20 45 20 15

 

German pest proved superior to other materials in 1928 and 1929.
Results with sand and combinations of pest and sand varied from

year to year.

Table g.-Ԥgoting3softwood cutting in various materials. (192813

 

 

Rubel Adams.
Per cent '“Per cent
__fi No. rooted No. rooted
German Pest 75 86.6 50 86.6
American Peat 75 40.0 50 90.0
German Pest and
sand 75 6.6 50 10.0
Sand 75 10.6 50 13.5

 

Table 4 shows the results of rooting softwood cuttings in
various materials in 1928. .Similer results were obtained in

1929, exeept that the percentages of stand in send and in poet

and sand were lower.

[26b

 

—-~

Fig. 5.- Note the secondary growth
starting just above the last large leaf.
This is the stage of growth at which
softwood cuttings should be taken.

 

Fig. 6.- A softwood cutting
ready for planting in the
cutting be .

Table 5.- Time of taking hardwood cuttings as a factor in
rooting. (1929) (German peat used as the
rooting mediuml.

 

 

Rubg;_ Pioneer Cabot Adams
Per cent Per cent Per cent Per cent
HQ; rooted No. rooted NO. rooted Nb. rooted
February 19 84 92.8 40 80.0 50 64.0 67 58.2

April 2. 25 92.9 59 89.8 45 84.4 58 31.5

 

Cuttings which are taken in the winter and stored will
root as well as those taken early in the spring and placed at
once in the propagating frames. It will be observed, however,
that Adams gave lower percentages of rooted cuttings than the
other varieties. This was true of cuttings of this variety
taken.in February and in April. The new shoots of Adams,
and sometimes of Cabot, are somewhat susceptible to winter
injury. Cuttings made from this winter-injured wood root
very poorly. It would be prudent, therefore, to take
cuttings of such varieties in early winter and stere them
in a cool, moist cellar. This would be especially desirable
if the site on which the plants are growing is particularly
liable to be subjected to low temperatures during the winter.

-14-

Table 6.- Time of taking softwood cuttings as a factor
in rooting. (1928) (German peat used as =
rooting mediuml.

fl "

 

 

 

Rubel_ _ Pioneer _fimeabot
Per cent Per cent Per cent
are, rooted No. rootedfij» No. rooted
July 5 42 33.5 35 71.4 18 88.8
July 15 54 100.0 58 92.1 27 100.0
July 25 58 81.6 24 58 .5 15 100.0
August 25 54 0 25 8.6 15 25.0

 

. Approximately the middle of July proved to be the best
' time for taking softwood cuttings in 1923 and in 1929. Only
a small percentage of cuttings taken in late August of both
years produced roots. Fruit bud differentiation had taken
place in many of the lateral buds. However, due to the
differences in growing seasons in the same and different
sections of the country, probably the condition or stage of
development of the new growth would be a better index as

to the proper time of taking softwood cuttings than exact
dates. The blueberry plant makes an initial flush of
growth early in the growing season, usually terminating

the latter part of June or early in July in southern
,Michigan. Secondary growth then takes place from a few

of the lateral buds. The best time for taking softwood
cuttings, regardless of date, is Just as the secondary
growth is starting. (Fig.6).

. s L .
.—
.
v
w
w
l ' -
. . , . _
l i
, .-
e
,- O
\
v
v \

I.

\. -
o
n
.
r
I
K

 

N44

 

 

Fig. 7.- A propagating frame recently planted with softwood
cuttings. Note that they are planted in a slanting position.
Hardwood cuttings are planted in the same manner. The glass sash
on the frames are open for ventilation.

-15-

Influence of Chemical Treatments on Rooting Cuttings.

As several investigators have reported success with
chemical treatments in rooting cuttings of other plants,
some of the most promising materials were used in this
experiment. The solutions were made at the strengths
indicated in Table 7, and the cuttings were allowed to
stand in the solutions for 24 hours prior to planting.

Table 7.0henica1 treatments with hardwood cuttings.
(1929) _(German peat rooting mediqu_

 

 

 

Rubel Pioneer Cabot
Per cent :Per cent Per cent
No, rooted No. rooted No; rooted
Potassium.permanganate
.01 mol. sol. 20 95 20 100 20 65
Potassium permanganate
.001 mol. sol. 20 100 20 95 20 55
Copper sulphate
.001 mol. sol. 20 90 20 75 20 50
Manganesesulphate
.001 mol. sol. 20 95 20 90 20 55
Potassium ferro cyanide
.001 mol. sol. 20 100 20 100 20 50
Sucrose (2% solution) 20 100 20 90 20 55
Acetic Acid (.52% vinegar
solution) 80 95 20 90 20 65

Check 80 95 20 B5 80 80

The chemical treatments were used in both 1928 and 1929
with very nearly the same results. There is some indication

that in some instances somewhat better results were obtained

-15-

with certain chemical treatments. 0n the whole, however,
the differences have not been great or consistent enough
to indicate that the treatments are of any great value.
The treatments appeared to be harmful with softwood
cuttings in some instances, the succulent wood turning

black after contact with the solution.

The Influence of Temperature and Aeration of Rooting
"'“ : Cuttings.

An attempt has been made in these investigations to
determine the relative influence of temperature and aeration
on rooting blueberry cuttings. It has already been shown
that the solar frame, box frame, and span frame, all of which
have the suspended cutting bed, have all been superior to
the cold frame for rcoting_both hardwood and softwood cuttings.
Tables 8 and 9 give the average temperatures of the rooting
media in these various types of propagating frames throughout
the season. It will be noted in Table 8 that the average
soil temperature of cold frame at 7 A.M§ was only 1.60 1.
lower than that of the solar frame, the noon temperature of
the cold frame was only l.4° F. higher than the solar frame.
and the evening temperature of the cold frame was but 5.5° F.

lower than the solar frame. In spite of these small differences

|~‘

-17-

in temperature, the cold frame produced only 25 per cent of
rooted hardwood cuttings of Pioneer, while the solar frame
produced 89.8 per cent. The same comparison can be made
from the data presented in Table 9. These facts suggest that
the better rooting in the suspended types of propagating

beds was due to better aeration, rather than temperature

differences.

Table 8.. Degrees F., may 20 to July 11, 1929, of German peat
in different types of propagating frames.
(Hardwood outtingsL

 

 

 

Average at Absolute No. of times registerimg
77A.M Neon 5P4m max. Min. 80-84°r 85-90°F 91°F
0
Gfldunmme 59.5OF 7a.4°r 71.9°r 82 F 42°F 7 o 0
Solar v 60.9 71.0 75.4 ~85 48 11 a 0
Box " 61.8 72.2 77.0 90 45 9 11 1
Air 88 as s 4 0
Open " 8.5 75.5 76.8 95 59 8 15 5

 

 

 

 

 

 

 

 

Table 9.- Degrees F., July 26 to October 5, 1929, of German
peat in different types of propagating frames.
(Softwood cuttings).
Average at Absolute No. of times registering

O O
_7A;M Neon 5P.MZ max. Min. 80-84 F 85-90 F 91°F

 

Cold m:- oo.9°r 73.5% 74.5° 91°F 45 r 16
Solar " . 0.2 69.9 75.8 84 42 10
Box 7 62.4 72.2 75.0 94 44 15
Air 7 ~ 88 55 16

000$
Ol-‘OO

 

 

 

 

 

 

 

 

 

Fig. 8.- Rooted softwood cuttings in solar
and box frames. These cuttings were planted
July 14 and the photograph taken early in
October.

we.

-18-

Information is lacking with regard to rooting blueberry
cuttings in prepagating frames where the temperature is
definitely controlled. Ovservation indicates that low
temperatures, while not harmful to the cutting,do not
stimulate root formation. Very high temperatures are likely
to cause death. It is possible that certain localities,
due to differences in temperature, may prove more desirable

than others for rooting blueberry cuttings.
Notes on.Handligg Cuttings

The improved varieties vary considerably in their ability
to develop roots. Rubel, for instance, roots more readily
than the other varieties, either from hardwodi or from soft-
wood cuttings. Pioneer is probably the most difficult of all
the varieties. Hardwood cuttings of this variety usually root
satisfactorily, but the softwood cuttings are unreliable,
often giving poor results. .Admms and Cabot root readily from
hardwood cuttings provided the wood has not been winter-injured.
Softwood cuttings of each of these varieties root readily.
Both types of cuttings of Harding root successfully.

Hardwood cuttings are made from the new shoots produced
the previous season. Wood showing any winter injury should be

discarded. The upper third of most shoots is also usually

I.

 

 

-19-

discarded, due to the prevalence of fruit buds (Fig.4). The
cuttings are made about four inches in length, the lower out
being made directly behind a bud and the upper out being made
just above a bud (Fig.4). To facilitate handling, the butts
of the cuttings should all be placed the same way. Bunches
of cuttings can be held together conveniently with rubber bands.
Softwood cuttings (Fig.5 and 6) are made of the current
season's growth. They should be from three to four inches
long and the cuts made in the same manner as for the hardwood
cuttings. A11 leaves are removed except the upper two, and
the upper half of each of these is cut away. Succulent wood
should be discarded as cuttings made from this wood turn black
soon after being placed in the cutting bed.
A tray four inches deep, covered on the bottom with hard-
ware cloth of one-eighth inch mesh, is placed in the top of
the propagating frame. This tray is filled with German peat
that has been thoroughly soaked with water. The post should
not be tamped or packed, simply smoothed off. The cuttings
are pushed into the peat at a slant (Fig.7). Do not press
the peat around them. Plant in rows two inches apart and space
the cuttings slightly over an inch apart in the row. Sprinkle
thoroughly after the cuttings are in place.
The cuttings should be covered with a glass sash, and shade
made of burlap should be placed about four inches above the sash.

This shade should be kept on the sash at all times.

 

Fig. 9.- A view of part of the nursery at
the South Haven Experiment Station. On the
right, plants grown from softwood cuttings
rooted the year previous. Center, blue-
berry seedlings one year old. Left-center,
trays of hardwood cuttings taken from the
propagating frames after rooting had taken

place e

:44,

-20...

The peat should be kept saturated. Any excess water will
drain off readily through the wire mesh at the bottom.of the
tray. During cool weather in the spring the cuttings often can
go several weeks without watering. During hot summer weather,
they may require watering once a week.

Ventilation should not be given until the cuttings are
rooted; then it should be afforded gradually. After the sash
has been removed, the burlap shade should remain over the
cuttings for a few weeks. If the solar frame is used, it wt 11
be necessary to open.the lower sash, to prevent extremely
high temperatures in the frame. The box frame has one of the
boards on the side hung on hinges. 0n extremely hot days this
board should be lowered.

The frames should be examined at least twice a week to
see that the peat is well supplied with moisture, and to remove
all cuttings that are dying. This sanitation measure is very
important, for destructive fungi may spread from the dying
cuttings and cause considerable loss. Cuttings that do not
appear healthy should be removed when first observed for they
will not form roots and they are a menace if left in the
cutting beds.

Cutting beds used in the propagating frames should be movable
in order that the same frame may be used for a planting of
hardwood cuttings, followed by one of softwood cuttings. The
hardwood cuttings are usually rooted by late June or early
Jfily. The tray can then be removed and placed on the ground

where it can remain the balance of the summer. Another tray

can then be placed in the frame, filled with peat, and used

-21-

for softwood cuttings.

Hardwood cuttings can be carried through the winter
out-cf-doors at South Haven provided some protection is
given. Bight-inch boards should be placed around the
outside of the trays and soil banked against them. .Additional
past or sand should be sifted over the cuttings, leaving
most of the tops exposed. Lath shade laid over the top
helps to catch and hold the snow and thereby tends to
prevent alternate freezing and thawing. Softwood cuttings
are not well rotted until October. The sash and shades
should be removed as soon as possible after rooting has
started so that the cuttings will drop their leaves and
harden their wood to some extent. For best results, soft-
wood cuttings should be wintered in a cold pit or cool,
moist cellar. The roots are so fine and soft that the
least amount of heaving breaks them.

In the following spring, the largest of the rooted
hardwood cuttings can be set permanently in the field.

The smaller rooted hardwood cuttings and all of the
rooted softwood cuttings should be grown a year in the
nursery row before setting in the field.

Growing gluebergy Seedlings:

Blueberry seedlings are of little direct commercial
value due to the variability in the type of fruit produced
on individual plants. However, a knowledge of successful

l -
.
.
K. I
7.... .
l .
«Au . ‘
.
, s
. . I .
. r I.
v s I
‘ e
_
o
n
. .‘
. .
.
n ,
- r
. ul
,
I ,.
.
i
.2 .
.
O
.
.
, _ ..
. .
v .
,
J
.
.
Wm ..
.
.
r
e.
c

-22-

methods of growing seedlings is essential for the investigator
in search of new varieties.

If seeds of the blueberry are planted as soon as they
are removed from.the mature fruit, a large percentage germinate
in five to eight weeks. If the seeds are removed and dried
they are likely not to germinate for two years. Very good
results have been obtained by removing the seeds from the
fruit and planting at once in trays of German peat, and
then covering lightly with fine, sifted peat. In November,
half of the seedlings were placed in a greenhouse and half
were placed in a cold pit. At that time, the seedlings were
about one-half inch in height and had their first two leaves.
Those which were carried through the winter in the greenhouse
were planted in beds of pest and sand about May 1. Those
which were carried through the winter in the cold pit were
transplanted to other trays and set outaof-doors under shade.
Early in July, they were transplanted again to beds of peat
and sand. At the end of the growing season, the seedlings
carried through the winter in the greenhouse had produced
three or four shoots each from.eight to ten inches long.
These seedlings were at least three or four times as large
as those carried through the winter in the cold pit. Though
seedlings can be started in the fall and brought through the
winter in a cold pit; the use of a greenhouse will increase
their growth to such an extent that they can be planted in the
field one year earlier than would be possible otherwise.

 

v...
Q

 

 

 

 

 

Fig. lO.- At the right is a box frame and at the left a
cutting tray showing the construction of each. The hinged
board in front is open as it would be on very hot days.
The cutting tray is in place ready to be filled with peat.
See text for complete description of this type of frame.

 

4.260..

-23-

Discussion

The material presented in this paper has been gathered
from five years of investigation. The conclusions drawn are
substantiated by eXperiences derived from handling thousands
of cuttings in a commercial manner. Approximately 35,000
cuttings were handled in 1989, being half hardwood and half
softwood. The success of the large and small scale experiments
leads to the belief that the propagation by cuttings of the
highbush blueberry is entirely practicable, that a considerable
degree of success can be realized, and that plants can be
produced at a reasonable cost. The rooting of blueberry
cuttings requires considerable equipment, a comparatively long
time, and more or less constant attention. Lack of attention
will certainly result in fanure. It is not likely that blue-
berry plants can ever be sold as cheaply as some other fruits
such as currents, gooseberrics, and grapes, but it is probable
that they can be produced at a price low enough to permit

commercial growing of the improved varieties.

-24-

,Acknowledgements.

The writer wishes to express his appreciation
to messrs. V. R. Gardner, J. W. Grist, F. 0. Bradford,
of the Department ofHHorticulture, and Alex.Laurie,
now of Ohio State University, for many valuable suggestions
and criticisms and aid in organizing this manuscript.
Mr. W. 0. Button of the Department of Horticulture

contributed several photographs.

-25-
Summary

Attempts to root hardwood cuttings in the greenhouse
during winter were generally unsuccessful. Root cuttings
also gave negative results.

Four types of propagating frames were used in these
investigations; the solar frame, the box frame, the open
frame, and the cold frame. The use of the cold frame
resulted in a low percentage of rooted cuttings. The
open frame was only fairly satisfactory. The solar frame
and the box frame were equally successful. The box frame
is recommended because it is only half as expensive to
build and requires less attention in operation.

German.peat proved superior to American peat, sand,
sphagnum.moss, and combinationd of pest and sand asgrooting
medium.

Hardwood cuttings of varieties like Adams and Cabot which
are susceptible to winter injury should be taken in early
winter and stored in a cool, moist cellar. Where winter injury
is not a factor, satisfactory results can be obtained by
taking the cuttings late in march or just before growth starts
and planting directly in the propagating frames.

Softwood cuttings of all varieties should be taken as
soon as the plant starts its secondary growth. In Southern

Michigan, this is usually early in July.

-25-

Chemical treatments were of little value in stimulating
rooting of hardwood cuttings. With softwood cuttings their
use may be even detrimental. ’

Information on rooting cuttings under carefully controlled
temperatures is lacking. Rooting media in the four different
types of propagating frames showed only slight temperature
differences; nevertheless, the solar frame, box frame, and
cpen frame, each having a suspended propagating bed allowing
better aeration, gave high percentages of rooted cuttings as
compared with the cold frame. These facts indicate that the
better rooting in the suspended cutting beds was due to
aeration, rather than temperature difference.

varieties vary in their ability to root from cuttings.
Rubel roots the most readily of any of the cultivated varieties
from either hardwood or softwood cuttings. Hardwood cuttings
of Pioneer root fairly readily, but peer results followed the
use of softwood cuttings. The new shoots of Adams and Cabot
are susceptible to winter injury. Cuttings made from injured
shoots will not root, but both varieties root readily from
sound cuttings. They also root readily from.eoftwood cuttings.
Both types of cuttings oi'Harding root succesfully.

Blueberry seedlings can be grown fairly easily if the seeds
are removed from the mature fruit and planted at once in German
past. They can be carried through the winter in a greenhouse or,
at South Haven, in a cold pit. Winter growth under glass in-
creases_growth so that they can be planted in the field one year

earlier than would otherwise be possible.

fl.

-27-

Literature Cited

1. Coville, F. V., Experiments in Blueberry Culture,-
U0 so Do A. Bllre Of P10 Indo’ 3111. 193’ 1910.

a. Dawson, J., Garden and Forest, Page 183, 1888.
3. munson, W. M., 17th Ann. Rep. Me. Agr. Exp. Sta. 1901.

4. Card, F. W” Bush Fruits.- R. I. Agr. Exp. Sta. Bul.
91, 1903. Also R. I. Agr. Exp. Sta. Rept. 1903.

5. Coville, F. V., Directons for Blueberry Culture,
U. S. D. A. Bul. 974, 1921.

6. Beckwith, C. S. and Coville, 3., Blueberry Culture,
No Jo A822. EXPe Sta001re 200, 1987.

7. Crowley, D. 1., 36th Ann. Rep. Wash. Agr. Exp. Sta. 1926

8. Mbwry, H. and Camp, A. F., Blueberry Culture in Florida,-
Fla. Agr. Exp. Sta. Bul. 194, 1928.

9. Hildreth, A. C.,- Proc. Am. Soc. Hort. Sci. 1929.
10. Swingle, V. T. and Robinson, T. R., and May, Jr., E.-

The Solar Frame for Rooting Citrus and Other Subtropical
Plants., U. S. D. A. Cir. 310, 1924.

 

1‘

I.
i

Wad.

ROOM USE ONLY

 

‘0

  
    
      
    

. I x l.’ r
k’QI-‘i 0‘ p f-

) .
& II

5a

. . I ’ f I. ‘ ' ‘ I v . V‘ . I a
A. ’ . ‘ _ _-‘ .0 ’ - , ‘ .. _ . ‘ ‘. ‘U’l. \’ . _.‘_:.. q
. _ . . . . . . . ‘ 1“ .7 .m

.-I ' "$1.1

      

.v .‘ ’ ‘ ‘, ‘I-r‘ ." f > CM} I. "ll.‘ ,
P CI, . A i V: _, .. 1 . . u ,' . IQ t‘ . 1 . \ '.r «it ~ 0 ,
'3‘, ‘ . 1 '.j_ .' -‘ . ‘ 'f- 7? .‘: 1'~.'—' “A“ 3!:-\.,.v‘§v'$“.;q
I 1 . ‘ l .7 - “ e ..'..‘. .4

        

         
 
   
 

.53.

,a
, §
r
«5"
‘ .-
fl
I
- +3 2: L- .3
i ‘.l V.
‘
y‘Tv
...
o -)"b a,
.a -
"'_:"1'
"I

‘ .P
‘i
u-‘

h

J.
b
”-
-
' '.
f:
-
'a,i
.l's
, C
- .-
l, .
.
r
a
-
.
\JLV. ,
T
v
.
N I
,.
a
'1
,e
‘1
A
g
1’
"V _
-
o
' V
II. n
' . I
ii ‘I '-
..' ' .' A ‘
. a
A C
'—r
v '

 

       
 

v I ‘ .'~ .. . ' . .V. II
.,.:~. 4: 3. ,‘s we. ..... ‘-
, ', \ .' ' J . ' ‘ ~‘-. . ‘ . ,. - ‘-, . 0 |-.‘.- .‘
. 4" 2“" , If I.‘ :~\' 1.5. . ., - l \ 3| _ u . .', _. . £k¢
. .- 1 -.‘ . "- .»
'a .I_ .’ 4 . . ‘ j'. -'. ,. . _. ‘7 _ ‘;¢~A"\.-‘.7“,..
' ‘

  
       

    
  

    

   

. v ' . v,- |

1 ‘ I “A" ’4 I ' l *>‘ .t ‘
A Fix—“rm; ",-‘."31.‘q. "3;::L;.'I;.}z:"__.'3‘ :' p 4', ‘. _ Q
w’émmm- e :9, . ,. .
.‘U.’N . .L (323% f ', |-,_L‘- '°"_.__ gl'fs‘r La

 

HICHIGQN STQTE UNIV. LIBRQRIES

I III “I ||||H|l||| l

 

31293005850312