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taken in February from a tree sixty years old; such cuttings rooting
better in sand than in sand-peat (1:1), better in the moist air of a green-
house at 70° F. than in a sweat bench at higher temperatures. Rooting was
somewhat improved by treatment for 24 hours with indolebutyric acid
(100 mg./l.), but improvement was not very great and this treatment was
sometimes injurious. He found that small cuttings, lateral twigs, root
better than large cuttings, terminal shoots, with all taken from the lower
part of the tree, and that winter, especially late winter, is apparently a
better time to take cuttings than spring, summer, or fall.

Snow (94) took cuttings in August from trees ten years old and planted
them in outdoor beds, covered with sash at night, in a six-inch layer of
sand-peat over old horse manure. They were there carried through the
winter mulched with hay, rooting the following summer. There was 35
percent rooting of those which had been treated only with water, 47.5
percent rooting of those which had been treated with indolebutyric acid



30 MASS. EXPERIMENT STATION BULLETIN 382

(25 mg./l., 6 hr.) followed by treatment with a dust containing indole-
butyric acid or naphthaleneacetic acid, but no benefit from the solution
treatment alone. Best rooting was of cuttings farthest from the terminal,
cuttings taken from lateral branches of lateral branches in the lower part
of the tree.

Rooting of cuttings from very young trees, better in sand-peat than in
sand, was improved by treatment with indoleacetic acid (200 mg./l., 24
hr.) (109).

Deuber got about 50 percent rooting of cuttings of lace-bark pine from
a tree ten years old and he mentions the rooting of cuttings of Scots pine,
Austrian pine, and a few other species by other investigators. In the
present limited state of our knowledge, propagators working with these
and other pines will probably do well to take cuttings, laterals not termi-
nals, from the lower part of the trees in late winter. Cuttings of lace-
bark pine, a variety of mountain pine (61), and white pine have sometimes
rooted better after treatment with indolebutyric acid; and this chemical,
if used, should probably be applied to dormant cuttings in a relatively
concentrated solution for a relatively short time.

Poncirus trifoliata. Cuttings which were taken here in mid-December and
inserted in sand-peat rooted 60 percent in 9 weeks after treatment with
naphthaleneacetic acid (100 mg./l., 17 hr.). Untreated cuttings and those
similarly treated with indolebutyric acid were alive but not rooted at the
end of that time.

Populus, poplar. Hardwood, April, cuttings of white poplar and black
poplar rooted poorly without treatment, very well after treatment with
indoleacetic acid (50 mg./L, 30 hr. or 100 mg./l., 18 hr.) (65). Rooting
of October cuttings of quaking aspen and March cuttings of large-toothed
aspen was much improved by treatment, the former with indoleacetic acid
(100 mg./L, 24 hr.) (109), the latter with indolebutyric acid (10 mg./l.,
27 hr.) (91). Late November cuttings of cottonwood, untreated, rooted
well when buried in a cold pit for about two months before' being planted
(52). Treated hardwood cuttings of quaking aspen rooted better in sand
than in sand-peat (91). Rooting of softwood, July or early August,
cuttings of white poplar and of a hybrid was much improved by treatment;
indoleacetic acid (50 mg./L, 24 hr.) being effective with the former (65)
and indolebutyric acid (20 mg./L, 12 hr.) with the latter (1).

Potentilla fruticosa is easily propagated by softwood cuttings. Taken here
in early July, they rooted 100 percent in sand in 3 weeks whether or not
they were treated.

Prunus spp. The best time to take softwood cuttings is, generally speaking,
in late spring and early summer. Treated cuttings of three plums and a
cherry rooted best if taken immediately after growth had stopped (81);
similar cuttings of another cherry, if made of tips of shoots taken shortly
before they became woody (11). Indolebutyric acid (15 or 20 mg./L,
24 hr.) markedly improved the rooting of such cuttings of both plum and
cherry (81). Cuttings of a species of Prunus taken in mid-July rooted 90
percent in 38 days after treatment with naphthylacetamide (1:1000, in
powder), 5 percent without treatment (104). A few other species are
discussed separately below.

Prunus ceo'asifera, cherry plum. Softwood cuttings, made in spring of
terminal shoots which were still growing, rooted 100 percent in 4 weeks



PROPAGATION OF TREES AND SHRUBS 31

after treatment with naphthaleneacetic acid (30 mg./l., 12 hr.), the most
effective root-inducing substance for this species, 20 percent without it
(82). Similar cuttings responded to indolebutyric acid (2 to 5 mg./gm.
talc, or, by the concentrated solution-dip method, 4 mg./cc.) (49).

Prunus glandidosa, dwarf flowering almond, is not difficult to propagate by
untreated softwood, July, cuttings (14, 44), made with the basal cut at
the base of the current season's wood (46) and planted in sand-peat (14).

Prunus incisa can be propagated by softwood cuttings taken with a heel
early in the season or when the new shoots are about three inches long
(105). Rooting of late summer cuttings was improved by naphthalene-
acetic acid (25 mg./l., 24 hr.) (113).

Prunus japonica. Late June cuttings, untreated, rooted about 50 percent
when made of tips, not basal parts, of young shoots (70).

Prunus Laurocerasus, cherry laurel, is easily propagated by late summer
cuttings (7). Untreated cuttings taken here in early August rooted more
than 90 percent in sand-peat in seven weeks. January cuttings rooted 80
percent in 34 days after treatment with indolebutyric acid (40 mg./l.,
6 hr.), not at all without treatment (119).

Prunus maritima, beach plum. Softwood cuttings taken here in late June
failed to root without treatment. They rooted 43 percent in sandy soil
after treatment with indolebutyric acid (12.5 or 25 mg./l., 20 hr.), less
well in sand or sand-peat or if cuttings were taken later.

Prunus Padus, European bird cherry. July cuttings rooted 32 percent with-
out treatment, 52 percent after treatment for 20 hours with a solution of
Auxilin containing indolebutyric acid 22 mg./l. (69).

Prunus pseudocerasus. Softwood cuttings, made of entire young shoots, are
successfully taken when such shoots are about three inches long (105).

Prunus subhirtella, Higan cherry. Softwood cuttings have been taken with
some success in early June (55). Taken here near the last of that month,
they did not root if untreated, but rooted 50 percent in sand-peat in 4 weeks
after treatment with indolebutyric acid (25 mg./l., 20 hr.).

Prunus tomentosa. Hardwood cuttings rarely root but softwood cuttings
root fairly well (127) in sand-peat or sandy soil. Untreated cuttings rooted
63 percent in sand, 80 percent in sandy soil when taken here in late May,
less well if taken a month later. Rooting is better if most of the leaves
are left on the cuttings (126). Taken here in mid-June, cuttings rooted
100 percent in sand-peat in 3 weeks after treatment with indolebutyric
acid (40 mg./l., 6 hr.), 35 percent in 7 weeks without treatment.

Prunus triloba, flowering almond. Cuttings root best if ma^le of new shoots
taken in spring (128) or when they are about three inches long (105). Root-
ing of July cuttings of the variety plena was improved by treatment with in-
dolebutyric acid (50 mg./l., 4 hr.) (125).

Pseudotsuga taxifoUa, Douglas-fir. Late winter cuttings rooted 80 percent
in sand-peat after treatment with indolebutyric acid (50 mg./l., 24 hr.),
less well without treatment or when taken in fall and early winter (43).

Pterocarya, wing-nut. The species, or some of them, can be propagated by
late-summer cuttings made of young shoots with a heel (80). Cuttings of
P. stenoptera rooted 90 percent in 3 weeks after treatment with Hormodin A
(20 B T I units), not at all meanwhile without treatment (118).

Puerarta Thunhergiana, kudzu-vine. Cuttings are decidedly respotisive to
treatments with potassium permanganate. Those treated 30 minutes with



32 MASS. EXPERIMENT STATION BULLETIN 382

a solution of 1 ounce in 8 gallons water rooted 86 percent in 30 days,
which was much better than the rooting of untreated cuttings or of those
treated with some ordinary root-inducing substances (75).

Pyracantha, firethorn. Cuttings are taken in summer (67) or fall (124).
Untreated cuttings of P. coccinea taken here in early August rooted 100 per-
in sand-peat and in sand. October (98, 125) and November (83) cuttings
have also rooted well. Rooting is better if thorns are removed (42) and if
the basal cut is at a node (14). Indolebutyric acid hastened rooting (125),
but indoleacetic acid (50 mg./l., 24 hr.) was more effective (83) and also
improved rooting of cuttings of P. atlantioides (72). September cuttings of
P. crenulata rooted, in 35 days, 6 percent without treatment, 75 to 100 percent
after treatment with indoleacetic acid (25 mg./l., 20 hr.), a treatment which
was of more benefit to cuttings of P. coccinea made of tips of shoots rather
than their basal parts (68). December cuttings of P. coccinea rooted 82 per-
cent without treatment, 100 percent with Hormodin No. 1 (102),

Pyrus, pear. Hardwood cuttings of most varieties of common pear are not
easily rooted, but some can be propagated by treated softwood cuttings.
Untreated cuttings did not root but those treated with naphthaleneacetic
acid (40 mg./l., 12 hr.) rooted 100 percent if made of growing shoots in
spring, 75 percent if taken in early summer when growth had recently
ceased (82). There was also good rooting of cuttings taken in spring
or early summer and treated with indolebutyric acid (20 to 40 mg./l., 24
hr.) (81); and 2 mg./gm. talc improved the rooting of early June cut-
tings of sand pear (49). Cuttings of Hood, an oriental pear, rooted 100
percent in sand-peat in three weeks after treatment for 24 hours with
Hormodin A (40 B T I units), not at all without treatment (117).

Quercus, oak. Cuttings from other than very young trees are not likely to
root much without treatment. Untreated July cuttings of English oak
did not root, but there was 56 percent rooting of cuttings from trees 6 to
8 years old which had been treated with indoleacetic acid (50 mg./l.,
18 hr.), 34 percent rooting of cuttings from a tree 20 years old similarly
treated with 200 mg./l. (65). Cuttings of red oak from mature trees
failed to root, but there was 82 percent rooting of February cuttings made
from the basal parts (wood more than one year old) of 4-year-old trees
which had been treated with indoleacetic acid (400 mg./l., 24 hr.), 22
percent rooting of untreated cuttings (109).

Rhododendron. As may be seen by reference to the table, early summer
cuttings of some species root well without treatment. That is true also
of cuttings of R. japonicum, R. racemosum (88), R. laetevirens (90), R. lap-
ponicum (105), R. yunnanense, and R. indicum (106). Cuttings of most
azaleas (9), R. maximum (5), and the common evergreen hybrids have been
more difficult to root although cuttings of some, e. g., the varieties Boule
de Neige, catawhiense album, and purpurcum clegans, rooted well without
treatment iy"^)-

Cuttings of many species root better or more rapidly after treatment
with indolebutyric acid, some effective concentrations of which are listed
in the table. For broad-leaved evergreen species and hybrids, a relatively
high concentration of indolebutyric acid (40 to 80 mg./l., 24 hr., or 12
mg./gm. talc (61) or 10 to 20 mg./cc. by the concentrated solution-dip
method (49) ) is usually needed. Cuttings of the hybrid album grandiHorum
taken here in late August rooted 62 percent in 5 months without treat-
ment, 92 percent in 3 months after treatment with 50 mg./l., 20 hr.



PROPAGATION OF TREES AND SHRUBS



33



Rooting of Cuttings of Rhododendron



Species and Time of
Taking Cuttings



Indolebutyric

Acid

Treatment



Rooted

with

Treatment



Rooted

without

Treatment



Lit.
Cit.



Percent Days Percent



Days



R. arhorescens

Late June 80 mg./l., 4 hr.

Latp May 12 mg./gni- *

Mid-July 5 ing./gm. *

Jl. calendulaceum

I^ate May 12 nig. /gm. *

Early Jiily 50 mg./l., 16 hr.

R. canadense

Early July 50 mg./l., 20 hr.

JR. canescens

Late June 12 mg. /gm. *

Hormodin A
Jl. CoUettianum

Late June 12 mg. /gm. *

R. dauricum

Mill- July 5 mg. /gm. *

Jl. gandavense

Late June 60 mg./l., 8 hr.

R. f^andavense (hybrids)

Early June 12 mg. /gm. *

Jl. hursutum

Mid-August 30 mg./l., 24 hr.

Jl. micranthum

Late July 10 mg./l., S hr.

Jl. minus

Late November 75 mg./l., 16 hr.

R. mixtum

Late June 90 mg./l., 10 hr.

Jl. molie

Mid-July 2 nig. /gm. *

R. mucronatum

Late Mav 2 nig./gm. *

Mid-June 30 mg./l., 4 hr.

R. mucTonulatum

Early July 50 mg. /I., IS hr.

Late June 12 mg. /gm.. *

R. nudijiorum

Late June SO mg./l., 4 hr.

R. ohtusum (varieties)

Early June 70 mg./L, 20 hr.

Late June 2 mg. /gm. *

Hormodin A
R. ohtusum var. japonicum

Late June 2 mg./gm. *

R. ohtusum var. Kaempjeri

Early July 50 mg./l., 4 hr.

R. ponticum „ „ , ,

Late June 40 mg./l., 24 hr.

R. pulchrum ,, „ _ ,

Late July 90 mg./L, 24 hr.

R. Tcticulatuni

Late July 40 mg./l., 8 hr.

R. roseum

Mid-July 12 mg./gm. *

R. Schlippenbachtj

Late May 12 mg./gm. *

R. Vaseyi

Late June 2 mg. /gm. *

Late June 10 nig. /I., 8 hr.

R. viscosepalum

Late July 25 mg./l., 6 hr.

R. viscosum

Earlv June 15 mg./gm. *

Late July 90 mg./l., 4 hr.

R. yedoense var. pou^hanense

Mid-July 2 mg./gm. *

Late July 50 mg. /I., 20 hr.

* Tn talc. ** Work done here.



63 Same, but better
roots



100
100



75
100



75
100

50

100

100

75

90

100

50

80

50

100
70

100
75

73

93
100
100

100

85

80

100

100

50

75

75
60

100

50
100



100
100



45
83

54
80

50

92
42

61

53

70

47

80

91

150

147

68

33
73

87
46

62

49
37
49

34

45

63

35

35

68

76

76
105

52

47



22
64



2 5


25
50

27


30


25
80


90
60


20



100
10

74


56

86

25-75

56

100

85

80

100

100






30



45
33



54
80



92
42

61

53

105

47

96

91

150

147

68

33

73

110
46



63
37
49



112

50

56

68

76

76
105

90



47

100 (but more
slowly)

25 2 2

12 60



125



61
61



61

118

61
61
90
61



61



61

125



61

125

90

61

117

61

125

88
S8
88
61
61
61



34 MASS. EXPERIMENT STATION BULLETIN 382

Cuttings of Rhododendron mucronatum, R. pulchrum, R. obtusum, and R.
yedoense var. poukhanense will root at almost any time (9), but cuttings of
most azaleas, deciduous species, root best if taken in spring or early summer
when the wood is soft (90, 125), much less well in fall or winter (61). Best
rooting of cuttings of R. calcndulaceuin, R. mucronulatum, R. viscose paluni,
and R. canadense followed when they were taken here before rather than after
the middle of July.

A good time to take cuttings of broad-leaved evergreen Rhododendrons,
including the named hybrids, is August (9, 77) or after the leaves on the
newest growth have become dark green. They have also rooted well
when taken in September, October, or early November (61, 77). Such
cuttings are made of terminal shoots, without flower buds, cut through
the basal ring (61). Nearing and Connors (77), using different methods,
successfully shorten cuttings to three inches below the lowest of the
three to five leaves which are left on the cutting.

The basal cut may be made in wood of the current year in the case
of Indian and Kurume azaleas (9), but cuttings of other azaleas are
usually made with a heel (9, 61) or with the basal cut at the juncture of
the wood of the current and previous year (105).

A mixture of sand and peat, 1:1 or 3:2, is a good rooting medium (9, 90),
better than sand (44, 88) and better than a mixture (2:1:1) of sand, peat,
and loam. Azalea cuttings rooted better in sand-peat which had l)een
previously used than in a freshly prepared mixture (44). Bottom heat
may benefit fall cuttings but is unnecessary for those taken in July and
August (9).

Broad-leaved evergreen Rhododendrons can also be propagated, be-
ginning in July or when new leaves have fully developed, by leaf-bud
cuttings consisting of one leaf of the current year's growth, its axillary bud,
and an attached bit of bark and wood or piece of stem about a half inch
long (61, 88). This leaf-mallet type of cutting, so set as not to cover
any of the blade of the leaf with rooting medium, rooted in higher per-
centages than stem, terminal cuttings (61). Such cuttings, in sand-peat
at 70 to 75° F., rooted in 13 weeks without treatment or in 10 weeks after
treatment of the mallet or heel with indolebutyric acid (60 mg./l., 8 to
24 hr.) (89). Leaf-bud cuttings of the variety purpureum elegans rooted
100 percent in 15 weeks with treatment (indolebutyric acid 120 mg./l., 20
hr.), 88 percent in 18 weeks without it (90).

Rhodotypos scandens. Softwood, late spring, cuttings root well. Taken here
in late May, they rooted 86 percent in sand in 8 weeks witliout treatment,
100 percent in 3 weeks after treatment with indolebutyric acid (25 mg./l.,
24 hr.). Late June cuttings rooted 84 percent in 7 weeks after treatment
with indolebutyric acid (1:1000, in talc), not at all meanwhile without
treatment (104).

Rhus, sumac. Untreated July cuttings of fragrant sumac rooted 80 to 100
percent in sand-peat, less well in sand (66). Cuttings of staghorn sumac and
smoke-tree {Cotinus Coggygria or Rhus Cotinus) are taken in England (80)
in late summer, but smoke-tree is not readily propagated by cuttings (73).

Ribes. Garden currant can be propagated by September or October cuttings
set in the field, the upper bud level with the soil surface, and given a
protective mulch in winter (121). That and other species can also be
propagated by summer cuttings. July cuttings of European black cur-
rant, alpine currant (44), and northern red currant (65) rooted well.
Gooseberry cuttings may root less readily (5, 105), but untreated cuttings.



PROPAGATION OF TREES AND SHRUBS 35

of the variety Poorman which were taken here in mid-July rooted 70
percent in sandy soil, 32 percent in sand. Late June cuttings of alpine
currant rooted 77 percent in 22 days after treatment with indolebutyric
acid (20 mg./l., 24 hr.), 39 percent witliout it (57). Rooting of October
cuttings of R. Grossularia was improved by treatment with naphthalene-
acetic acid (50 mg./l., 24 hr.) (113).

Robinia Pscudoacacia, black locust, and its varieties can be propagated by
hardwood, winter and early spring, cuttings treated with indoleacetic acid
or naphthaleneacetic acid (100 mg./l., 24 hr.). Cuttings, six to twelve
inches long and about one half inch in diameter, were allowed to callus
for seven to ten days in moist sphagnum moss at 68° to 80" F. before
treatment. Stored in moist sand at 70° F. for about ten days following the
treatment, the}' rooted, in soil, more than 60 percent in the field, more
than 90 percent in a greenhouse (99).

Rosa, rose. Most hardy climbing roses and hybrids of R. mgosa, some
hybrid teas, and some hybrid perpetuals do well on their own roots (121,
122). Cuttings of some species are difficult to root (10), but hybrid per-
petuals, Polyantha roses, most hardy climbers, and some hj'brid teas can
be propagated by dormant, late fall or winter, cuttings planted imme-
diately in a cold frame or stored cool, in sand, during winter and planted
outside in spring (122). Rose cuttings are taken in late fall in England,
and untreated October cuttings of R. rugosa there rooted to the extent of
100 percent (10).

Greenhouse varieties of hybrid teas were most responsive to treatment
if cuttings were taken from canes of flowering wood just after petals
began to fall, and softwood cuttings rooted best if taken from garden
varieties of hybrid teas in August or from climbers and creepers in July
and August (62). Three buds are enough on a cutting (122). Sum-
mer cuttings of R. Hugonis, R. omeiensis, and prairie rose rooted better
if made with a heel (46) but all roses do not need one (121). There
was good rooting of three-node cuttings of hybrid teas made from
the basal portion of flowering shoots, the basal cut in the internode
below a node, the lowest leaf and the terminal leaflets of the remain-
ing leaves removed (62). Sand-peat, sand (62), and sandy soil (121,
122) have been used successfully as rooting media. Sandy soil gave
better results than sand with treated cuttings of a hybrid perpetual {27).

Indolebutyric acid in very low concentrations (48) is the most effective
of the known root-inducing substances for rose cuttings and some of the
results of work with it as described by Kirkpatrick (62) are here sum-
marized. Cuttings of several, not all, garden varieties of hybrid teas,
taken in August from flowering shoots, rooted as much as 50 percent
more after treatment with 2.5 mg./l., 24 hr., or 2 mg./gm. talc. Similar
cuttings of greenhouse varieties rooted in 15 to 20 days after treatment
with 1.25 to 2.5 mg./l., 24 hr., or 1 to 2 mg./gm. talc. Rooting of summer
cuttings of several climbers and creepers, also R. multitlora, was improved
b}' 5 mg./l., 24 hr., or 2 mg./gm. talc but at least twice these concentra-
tions were needed to induce rooting of cuttings of R. Hugonis. Treatments
did not affect rooting of Pernettiana hybrids. Dormant cuttings of
R. multiftora responded to 5 to 10 mg./l.. 24 hr., or 2 mg./gm. talc if treated
cuttings were then given a temperature of 65° to 75° F., not lower. Air
temperatures of from 60° to 80° F. proved to be best for quick rooting of
rose cuttings in general and it was necessary to give them heat at other
times but not in summer. Indolebutyric acid had little effect at temper-
atures of less than 60° F.



36 MASS. EXPERIMENT STATION BULLETIN 382

Rubus. Cuttings of Van Fleet raspberry, new shoots taken in May, rooted
well in 26 days (127), but some red raspberries are not readily propagated
in this way (115). Leaf-bud cuttings of a black raspberry taken in July,
made to include an axillary bud and a heel of bark and wood, rooted 100
percent in sand (100). This method is successful with some red rasp-
berries, not with others (115). Leaf-bud cuttings of several species, taken
in July or August before leaves began to mature, rooted in sand in 2
weeks or in half the time required for stem cuttings (112).

Salix, willow. Softwood, summer, cuttings of white willow (44), dwarf
willow (105), S. Elacagnos (66), and other species root readily in sand.
Rooting of late Jime cuttings of 5". Elaeagnos and early July cuttings of pussy
willow was, however, at least hastened by indolebutyric acid, 10 mg./l., 6
hr., for the former (83); 5 mg./l., 24 hr., for the latter (57).

Salvia officinalis, garden sage. Untreated cuttings taken here in October
rooted 100 percent in sandy soil in 6 weeks. Taken here in late June,
they rooted, in sand, 79 percent in 7 weeks without treatment, 100 percent
in 3 weeks after treatment with indolebutyric acid (40 mg./l., 24 hr.).

Samhucus, elder. Softwood, summer, cuttings of American elder (44), Eu-
ropean elder (66), European red elder, and 5". mclanocarpa (116) root well.
Cuttings of American elder, whole new shoots about five inches long,
root well if taken in spring (127) and that is a good time to take cuttings
of the varieties also (51). Sand is a good rooting medium (66, 127),
better, at least for some species, than sand-peat (116).

Sciadopitys (verticillata, umbrella-pine. January cuttings four or five inches
long, from trees about seven years old, were treated with indolebutyric
acid (20 mg./l., 20 hr.), planted in a mixture of sifted cinders three parts
and peat moss one part, and transplanted after three months to sand-peat
w^here they rooted 70 percent in 8 months (23). There was no rooting
meanwhile of untreated cuttings.

Sccurinega suffruticosa. Hardwood cuttings taken here in late March, buried
in sand at about 50° F. for one month and then planted in soil outdoors,
rooted 100 percent in 6 weeks whether or not they were treated.

Sorbaria sorbifolia. Untreated softwood, summer, cuttings, made with
the basal cut at a node, rooted 80 percent in sand at 60° P., less well at
70° (116).

Spirca. Softwood. July, cuttings root readily. There was 80 to 100 per-
cent rooting of untreated cuttings of S. Bumalda, S. salicifolia (46), S. Thun-
bergii, S. Billiardii (66), 5^. arguta, and S. Vanhouttci (116), but rooting of



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