MODES OF PROPAGATION BY DIVISION, _viz._ TAKING OFF SUCKERS, MAKING
LAYERS AND CUTTINGS, BUDDING, GRAFTING, AND INARCHING.
Properly speaking, there are only two modes of propagating plants,
viz.: by seed and by division. The first raises a new individual,
resembling the plant that produced the seed, as a child does its
parent, but not perpetuating any accidental peculiarity; and the second
method multiplies specimens of the individual itself. Species are
propagated by seed, and new varieties are raised; but varieties are
generally propagated by division, as they do not always come true from
seed. Propagation, by division, may be divided into two kinds:--those
in which the young plants root in the ground, such as suckers, layers,
and cuttings; and those in which they are made to root in another
plant, as in budding, grafting, and inarching.
_Suckers._--Sending up suckers, forming offsets, and throwing out
runners, are all natural ways of propagation that require very little
aid from the hand of man; and if all plants produced these, nothing
more would be required than to divide the offspring from the parent,
and replant it in any suitable soil. But only certain plants throw up
suckers, such as the rose, the raspberry, the lilac, the English elm,
&c. Offsets are only formed on bulbs, and runners are only thrown out
by strawberries, brambles, and a few other plants; and thus these modes
of propagation are extremely limited in practice. No plants produce
suckers but those that send out strong horizontal roots; and the sucker
is in fact a bud from one of these roots which has pushed its way up
through the soil, and become a stem. As this stem generally forms
fibrous roots of its own, above its point of junction with the parent
root, it may in most cases, when it is thought necessary to remove
it, be slipped off the parent and planted like a rooted cutting. As,
however, the nourishment it can expect to derive from its own resources
will be at first much less than what it obtained from its parent, it
is customary, when a sucker is removed, to cut in its head, to prevent
the evaporation from its leaves being greater than its roots can supply
food for. Sometimes when the parent is strong, part of the horizontal
root to which the sucker was attached is cut off and planted with the
young plant.
Suckers of another kind spring up from the collar of the old plant,
and when removed are always slipped, or cut off, with the fibrous
roots that they may have made, attached. Offsets are young bulbs which
form by the side of the old one, and merely require breaking off, and
planting in rich light soil. Runners are shoots springing from the
crown or collar of the plant, which throw out roots at their joints;
and which only require dividing from the parent plant and replanting in
good soil to make new plants.
_Layers._--Many plants, when kept in a moist atmosphere, having a
tendency to throw out roots from their joints, the idea of making
layers must have very early occurred to gardeners. Where the roots are
thrown out naturally, wherever a joint of the shoot touches the moist
earth, (as is the case with some of the kinds of verbena, which only
require pegging down to make them form new plants,) layers differ very
little from runners; but layers, properly so called, are when the art
of the gardener has been employed to make plants throw out roots when
they would not have done so naturally. The most common method of doing
this is to cut half through, and slit upwards, a shoot from a growing
plant, putting a bit of twig or potsherd between the separated parts;
and then to peg down the shoot, so as to bury the joint nearest to
the wound in the earth; when the returning sap, being arrested in its
progress to the main root, will accumulate at the joint, to which it
will afford such abundance of nourishment, as to induce it to throw out
a mass of fibrous roots, and to send up a leading shoot.
[Illustration: A Verbena layered.]
The only art required in layering is to contrive the most effectual
means of interrupting the returning sap, so as to produce as great an
accumulation of it as possible, at the joint from which the roots are
to be produced. For this purpose, sometimes, instead of cutting the
branch half through, a ring of bark is taken off, care being taken that
the knife does not penetrate into the wood; and at others a wire is
twisted firmly round the shoot, so as to pinch in the bark; or a knife
or any sharp instrument is passed through the branch several times in
different directions: in short, any thing that wounds, or injures the
shoot, so as to throw an impediment in the way of the returning sap,
and yet not to prevent the passage of the sap that is ascending, will
suffice.
Layering is a very common mode of propagating plants: and in nurseries
often every shoot of a tree or shrub is thus wounded and pegged down.
In this case, the central root is called a stool, from the verb, _to
stole_, which signifies the power most deciduous trees possess, of
sending up new stems from their roots when cut down. The seasons for
performing the operation of layering are during the months of February
and March, before the new sap begins to rise, or in June or July after
all the summer supply of ascending sap has risen; as at these seasons
there is no danger of injuring the tree by occasioning an overflow of
the ascending sap, which sometimes takes place when the tree is wounded
while the sap is in active motion. In most cases the layers are left
on twelve months, and in many two years, before they are divided from
the parent plant, in order that they may be sufficiently supplied with
roots. In nurseries, the ground is generally prepared round each stool
by digging, and sometimes by manuring; and the gardener piques himself
on laying down the branches neatly, so as to form a radiated circle
round the stool, with the ends rising all round about the same height.
[Illustration]
_Chinese mode of layering._--The Chinese method of layering, which
consists in wounding a branch, and then surrounding the place with
moist earth contained either in a flower-pot or a basket, is frequently
adopted in the continental gardens; and it has the very great advantage
of producing a young tree which will flower and produce fruit while yet
of very small size. It is generally applied to camellias, orange-trees,
and magnolias; but it will do equally well for almost any other tree
or shrub. When a plant is to be layered in this manner, a ring of
bark is first taken off, and then a flower-pot is procured, open on
one side, so as to admit the branch; and some moss being put at the
bottom of the flower-pot, it is filled up with earth, and a piece of
wood is placed inside the pot before the open part to prevent the
earth from falling out. It may be fastened in its place by wires
hung over a branch, or supported by four little sticks, tied to the
pot with string. The earth should be very moist before it is put into
the pot, and if the season be dry, it may be re-moistened from time
to time. When the layer is supposed to have rooted, a cut or rather
notch should be made in the branch below the pot, and afterwards it
may be cut off, and the young plant transferred with its ball of earth
entire to another pot or the open ground. A simpler way of performing
this operation is using a piece of lead instead of a flower-pot. A
modification of this plan was adopted by Baron Humboldt in South
America. He provided himself with strips of pitched cloth, with which
he bound moist earth round the branches of several of the rare and
curious trees he met with, after first taking off a ring of bark; and
when he returned to the same place some time after, he found rooted
plants which he brought to Europe.
_Cuttings_ differ from layers in being removed without roots from the
parent tree; and as the current of the ascending sap is stopped at
once by this separation, they generally require shading, which layers
do not; and also, occasionally, what gardeners call bottom heat, to
induce them to throw out roots. The branches most suitable for making
cuttings are those which grow nearest to the ground, especially those
which recline on it, as they have always the greatest tendency to throw
out roots; and the side shoots are considered preferable to those which
grow erect at the upper part of the plant. The best season for making
cuttings is summer, when the sap is in full motion; as the returning
sap is then most likely to form the ring or mass of accumulated matter
from which the new roots are to spring. It has been already mentioned
under the head of layers, that it is from the joints only that roots
can be expected to grow; and, accordingly, in making cuttings, the
shoot is divided at a joint; and it is reckoned best to choose the
joint at the point of junction between the young wood and the wood of
the previous season. The cut should be quite smooth; as if the shoot
be bruised, the returning sap will not be able to reach the joint in a
sufficient quantity to effect the desired end. Some plants are much
more difficult to strike as cuttings than others; but some, such as the
willow, the currant, the vine, &c., will throw out roots not only from
the ring, but from every part of the stem. These plants do not require
so much care as to cutting off at a joint; and in fact, will throw out
roots from whatever part may be put into the ground, but even they
succeed best when properly prepared.
The cutting being taken off, and the division at the joint being made
perfectly smooth, the greater part of the leaves should be cut off
close to the stem, with a sharp knife; and a hole being made in the
soil, the cutting should be put in, and the earth pressed close to its
extremity, or it will never strike out roots. This necessity of the
part which is to send out roots being fixed firmly in the soil, has
been already mentioned with regard to seeds, transplanted trees, and
layers; and this necessity exists with equal or greater force with
regard to cuttings. When these are made in a pot, the cutting will much
more readily strike (as gardeners call its throwing out roots), if it
rest against the side of the pot, or even against the bottom.
[Illustration: A cutting of the LEMON-SCENTED VERBENA (_Aloysia
citriodora_), prepared for putting into the ground.]
Cuttings may be struck in the open ground, and in the common soil,
without any covering; but these cuttings are only of those plants
which strike readily. When struck in pots, it is customary to fill
the pots half, or entirely full of silver sand, to prevent the stalk
of the cutting from having too much moisture round it. Those cuttings
which are most liable to be injured by moisture, such as heaths, &c.,
are struck in pots filled entirely with sand; but as there is no
nourishment to be derived from sand, most cuttings do best with their
lower end in earth, and with only sand about an inch, or two inches
deep, at the top of the pot, to keep the stem dry, and to prevent it
from rotting. The cutting, when prepared, should be buried to about the
second joint, and two or three joints with leaves should be left above
the soil. A few leaves to elaborate the sap in the case of herbaceous
plants, or evergreen trees and shrubs, are essential; for I have known
very promising cuttings of petunias, which had been some weeks in the
ground, and which had thrown out abundance of roots, entirely destroyed
by some snails having eaten all the leaves; and I am told that the
case is by no means an uncommon one. Cuttings of delicate plants are
generally covered with a bulb-glass pressed closely on the earth, to
keep a regular degree of moisture round the plants, and to prevent too
rapid an evaporation; but I have found cuttings thus treated very apt
to damp off, and have never succeeded in striking them, unless I took
off the glass to wipe it, every day. Cuttings of greenhouse plants, I
have been told by practical gardeners, strike best when put into the
pots as thickly as possible; and as they are generally well watered
when first put in the ground, if covered with a close glass, they
will frequently not require any watering afterwards. As long as they
continue looking fresh, they are doing well; and as soon as they begin
to grow they should be transplanted into small thumb pots, and supplied
moderately, but regularly, with water; changing the pots for larger
ones as the plants increase in size, and according to their nature.
Sometimes the pots are sunk into a hot-bed, to induce the cuttings
to take root, and this is called applying bottom heat; and sometimes
one flower-pot is placed within another a size or two larger, and the
outer one filled with water. All these expedients are more or less
efficacious; and the great object with all of them, is to excite and
stimulate the plant.
[Illustration: Cuttings of the COMMON HORSESHOE, and LARGE WHITE
FLOWERED GERANIUMS (_Pelargonium zonale_ and _P. macranthum_) prepared
for putting into the ground.]
[Illustration: A cutting of the CHINA ROSE (_Rosa indica_) prepared for
putting into the ground.]
_Slips._--When cuttings are made of the shoots from the root or collar
of the plant, or of little branches stripped off with a small portion
of the root or stem attached, they are called slips; and they require
no other preparation than cutting off the portion of bark smooth and
close to the shoot. Slips are generally taken off in March, but they
will also succeed if made in autumn. Cuttings of succulent plants, such
as of the different kinds of cacti, require to be dried for some time
after they are made, by placing them on a shelf in the sun. This is
done to prevent a waste of the returning sap; which, in plants of this
kind, is very abundant, and in a very liquid state.
[Illustration: A piping of a Carnation.]
_Pipings_ are cuttings of pinks and carnations, and indeed are
applicable to all plants having jointed tubular stems. They are
prepared by taking a shoot that has nearly done growing, and holding
the root end of it in one hand, below a pair of leaves, and with the
other pulling the top part above the pair of leaves, so as to separate
it from the root-part of the stem at the socket formed by the axils
of the leaves, leaving the part of the stem pulled off with a tubular
or pipe-like termination. Hence the name of pipings; and when thus
separated, they are inserted in finely sifted earth or sand, and a
hand-glass is fixed firmly over them. Most florists cut off the tips of
the leaves of pipings, but others plant them entire; and the pipings
grow apparently equally well under both modes of treatment.
_The principal points to be attended to making cuttings_ are, to cut
off the shoot at a joint, without bruising the stem; to make the
cutting at a time when the sap is in motion; to fix the end which is to
send out roots, firmly in the soil; to keep it in an equal temperature
both as regards heat and moisture; to cut off part of the leaves, and
to shade the whole, so as to prevent too much evaporation, without
excluding the light, which is wanted to stimulate the plant; to keep
the soil moist, but not too damp; and to pot off the young plants as
soon as they begin to grow.
_Budding_ has been compared to sowing a seed; but it may rather be
considered as making a cutting with a single eye, and inserting it in
another tree, called the stock, instead of in the ground. A young shoot
of the current year’s wood is cut off in the latter end of July or
August, or perhaps, if the season should be very moist, the first week
in September; and incisions are made longitudinally and across, on each
side, above and below a bud, so that the bud may be cut out, attached
to an oblong piece of wood and bark, pointed at the lower end. The leaf
is then taken off, but the footstalk is left on.
The next thing is to separate the bark with the bud attached from the
wood; and on the nicety of this operation much depends, as if any wood
be left in the bark the bud will not take; generally, however, if
the sap is in a proper state of movement, the wood comes out easily,
without leaving the smallest particle behind. The bud must be then
examined below, that is, on the side that was next the wood; and if it
appears fresh and firm it is likely to take, but if it looks shrunk
and withered it had better be thrown away, as it will never grow.
Slits longitudinal and across are then made in a shoot of the stock,
generally near the fork of a branch; and the bark is gently raised
by the handle of the budding knife, which is purposely made thin and
flat, while the piece of bark to which the bud is attached is slipped
into the opening, and the bark of the stock closed over it. This is an
operation that requires the greatest nicety and exactness; as unless
the inner bark of the bud fits quite closely to the soft wood of the
stock, it is in vain to hope that it will take. The operation is then
completed by binding the two parts together with a strand or strip of
bast mat, which in the case of rose trees is quite sufficient; but buds
on apple and pear trees are sometimes wrapped round with wet moss,
which is tied on by shreds of bast matting. In all cases, the strips
of bast should be left long enough to be tied with bows and ends, that
the ligature may be loosened and tied again without deranging the
position of the bud as soon as it begins to grow. The first sign of
the bud having taken, as it is called, is when the petiole of the leaf
(that was left on when the leaf itself was cut off,) drops, on being
very slightly touched with the finger; but the ligature should not be
loosened till the bud begins to throw out leaves; and then it should
be re-tied only a little slacker than before, until the bud is firmly
united with the stock.
[Illustration: Mode of budding a Rose-tree.]
Budding, though sometimes used for apples and pears, when the spring
grafts have failed, is most commonly applied to roses: it is, however,
occasionally used for inserting eyes in the tubers of the dahlia. It
sometimes happens that a large portion of a dahlia-root is found to
be entirely devoid of buds, or as the gardeners call them, eyes; and
when this is the case, in whatever soil the root may be planted, it
will never send up a stem. Other dahlia tubers, on the contrary, may be
found full of buds; and when this is the case, one of them is scooped
out, and a corresponding hole being made in the barren tuber to receive
it, the bud is fitted in, and the point of junction covered with
grafting wax. The tuber must then be planted in a pot with the budded
part above the soil; and the pot plunged into a hot-bed till the bud
begins to push, when the tuber may be planted out into the open ground.
What is called flute-grafting, is in fact, a kind of budding; as it
consists in taking a ring of bark, on which there is a bud, off a
shoot; and then supplying its place with a ring of bark, with a bud
attached, from another tree: placing the suppositious bud as nearly as
possible in the position of the true bud. Sometimes, however, this is
not thought necessary; and the ring of bark is taken from any part of
the stock; though it is always replaced by a ring of bark containing
a bud from the scion. There are many other kinds of budding, but as
the principles are the same in all, it is not necessary to detail them
here. The blade of the budding knife should curve outwards, to lessen
the danger of wounding the wood when making the incisions.
[Illustration]
_The principal points to be attended to in budding_, are; to choose a
fresh healthy bud; to separate the bark to which it is attached without
wounding it, quite cleanly from the wood; to make a clear incision
through the bark of the stock, and to raise it without wounding it from
the wood; to press the bark containing the bud, closely to the wood of
the stock so that no air can remain between them; and to perform the
operation in moist weather, not earlier than the last week in July,
nor later than the first week in September. Of these points the most
important are the joining closely the bark of the bud to the wood of
the stock, and the performing the operation in moist, or at least in
cloudy weather; and if these are attended to there is little doubt of
success. When the young shoot begins to grow, it is usual to shorten
the branches of the stock, so as to throw the whole vigour of the tree
into the bud. It is singular to observe that even when the operation is
most successful, no intimate union takes place between the bud and the
stock: they grow firmly together, but they do not incorporate, and the
point of union may always be distinctly traced.
It must always be remembered that a plant can only be budded on another
plant of the same nature as itself; thus a peach may be budded on
a plum, as they are both stone fruits, and both belong to the same
section of the natural order Rosaceæ; but a peach can neither be budded
on a walnut, which belongs to another natural order, nor even on an
apple or a pear, both of which, though belonging to the order Rosaceæ,
are kerneled fruits, and are included in another section.
_Grafting_ differs from budding in its being the transfer of a shoot
with several buds on it, from one tree to another, instead of only
a single bud; and as budding has been compared to sowing seeds, so
has grafting to making cuttings. The art of grafting consists in
bringing two portions of growing shoots together, so that the liber,
or soft wood of two may unite and grow together; and the same general
principles apply to it as to budding. There are above fifty modes of
grafting described in books, but only three or four are in common use.
In all kinds of grafting the shoot to be transferred is called the
scion, and the tree that is to receive it is called the stock; and it
is always desirable, not only that the kinds to be united should be
of the same genus, or at least of the same natural family, but that
they should agree as closely as possible in their time of leafing, in
the duration of their leaves, and in their habits of growth. This is
conformable to common sense; as it is quite obvious that unless the
root send up a supply of sap at the time the leaves want it, and only
then, the graft must suffer either from famine or repletion. For
this reason, a deciduous plant cannot be grafted on an evergreen, and
the reverse. The necessity of a conformity in the habit of growth, is
strikingly displayed in Mr. Loudon’s _Arboretum Britannicum_, in a
flowering ash grafted on a common ash; by which it is shown, that an
architectural column with its plinth and capital may be formed in a
living tree, where there is a decided difference in the growth of the
stock and the scion.
These examples show that no intimate union takes place between the
scion and the stock; and the fact is, that though they grow together
and draw their nourishment from the same root, they are in every
other respect perfectly distinct. The stock will bear its own leaves,
flowers, and fruit, on the part below the graft; while the scion is
bearing its leaves, flowers, and fruit which are widely different, on
the part above the graft. Nay, five or six grafts of different species
on the same tree, will each bear a different kind of fruit at the same
time. This want of amalgamation between the scion and the stock is
particularly visible in cases of severe frost, when the former is more
tender than the latter; as the graft is frequently killed without the
stock being injured. It is also necessary when grafted trees are for
any reason cut down, to leave a portion above the graft for the new
shoots to spring from; as otherwise the proprietor will find his trees
changed as if by magic, and instead of choice kinds only the common
sorts left. A rather droll instance of this happened some years ago, in
the neighbourhood of London; an ignorant gardener having a conservatory
full of very choice Camellias, and wishing to reduce the plants to a
more compact shape, cut them down for that purpose; when in due time he
found, to his great confusion and dismay, that the choice Camellias had
all vanished, and that he had nothing left but a number of plants of
the common single red on which they had been grafted.
_The proper season for grafting_ is in spring, generally in March and
April; in order that the union between the scion and the stock may be
effected when the sap is in full vigour. At this season a stock is
chosen of nearly the same diameter as the scion, whether that stock
be a young tree, or merely a branch; and they are both cut so as to
fit each other. One piece is then fitted on the other as exactly as
possible; and if practicable, it is contrived that the different parts,
such as the bark, soft wood, and hard wood of the one, may rest on
the corresponding parts of the other; and on the exactness with which
this is done, the neatness of appearance in the graft depends. It is
not, however, essential to the success of the operation that all the
parts of the scion should fit exactly on the corresponding parts of
the stock, or even that the two trees should be of the same diameter,
for if the bark and the soft wood correspond in any one point so as to
unite, it is sufficient to make the graft take. As soon as the scion
and the stock are properly fitted to each other, the parts are neatly
bound together with a strand of bast mat steeped in water to make it
flexible; and the bast is covered with a composition called grafting
clay, which is put on to keep the absorbent vessels of the wounded
parts moist, and capable of the alternate contractions and dilations
which will be necessary during the passage of the ascending and
returning sap between the stock and the graft. These directions apply
alike to all kinds of grafting; and the difference between the sorts
refers principally to the manner in which the corresponding parts are
cut to fit each other.
_Whip or Tongue Grafting_ is where both the stock and the scion are
cut in a slanting direction so as to fit each other, and a little slit
is made in the stock into which a tongue or projecting part cut in
the scion fits. The head of the scion is then cut off in a slanting
direction, slanting upwards from the part cut to receive the scion,
and the two are bound closely together with a strand of bast mat, or
wrapped in moss, and then covered with grafting clay. The part left on
the stock in a slanting direction above the graft withers, and is cut
off when the graft has taken. This is the kind of grafting generally
practised in nurseries, and it is the most useful, as it does not
require the scion and the stock to be of the same size.
[Illustration: The common mode of Whip or Tongue Grafting.]
_Peg Grafting_ is an old method seldom practised now; according to
it, the bark at the extremity of the scion is cut through, and the
central wood shaped like a peg; a hole is then bored in the stock to
receive the scion, and when the one is inserted in the other, the bark
of the two is brought together, so as to make but a very slight scar.
_Cleft Grafting_ is where the scion is shaped at the extremity like
a wedge, and a cleft is made in the stock to receive it. When this
kind of grafting is practised with trees and shrubs, the head of the
stock is cut off; but a modification of it is practised with succulent
plants, in which the end of the graft having been cut into the shape
of a wedge, is inserted into a cleft made in the side of the stock to
receive it, and the line of junction is covered with grafting wax. The
tubers of strong common dahlias may be grafted in the cleft manner with
choice sorts, as may the tubers of the herbaceous pæonies with scions
of the tree-pæony. This last is very useful, as cuttings of the Pæonia
Moutan remain weak for several years, while roots grafted in July or
August will flower the following spring.
_Crown Grafting_ resembles the last kind in requiring the head of the
stock to be cut off, but the scion is shaped at the extremity like a
wedge flattened on one side, and it is pushed in between the bark and
wood of the stock, with its flat side next the wood, till it is stopped
by a shoulder with which it is provided to prevent it going in too
far. In _Saddle Grafting_ the head of the stock is cut off, and the
extremity of the trunk is shaped like a long wedge; a long slit is then
made in the scion, and the divided parts are made to stand astride on
the stock. The bark is then pared off at the extremity, so that the two
parts may fit quite close; and a firm ligature is applied.
_Herbaceous Grafting_ is very badly named, as it gives the idea of
its being a kind of grafting applied to herbaceous plants; whereas,
in fact, it only means grafting with the brittle wood of the current
year, in opposition to common grafting, which is always performed with
firm wood, frequently of several years’ growth. Herbaceous grafting is
now generally used for trees of the pine and fir tribe, which, only a
few years ago, it was thought impossible to graft at all. The proper
time for this kind of grafting is when the young pine-shoots have made
about three parts of their growth, and are still so herbaceous as to
break readily between the fingers, like a shoot of asparagus. The shoot
of the stock is then broken off about two inches below the point, and
all the leaves stripped off for nearly two inches more, except two
sheaths of leaves, which are left, one on each side, close to the top.
The shoot is then split with a very thin knife between the sheaths of
leaves left on, and the scion, having had its lower extremity prepared
by stripping off the leaves, and cutting it into the shape of a wedge,
is inserted as in cleft grafting, and the parts are bound together
with list, or with a strip of thin woollen cloth. A cone of paper is
then put over the whole to protect it from the sun and rain, and the
graft is very seldom found to fail. Sometimes this kind of grafting is
applied to annual plants. The period chosen should be when the plant
is in its greatest vigour, and is just going into flower. The flower
stem is then cut off close to a leaf, and a slit is made in the stem
downwards. The scion is then taken off near the root of the plant, and
the end being cut into a wedge-shape, is inserted in the slit. The
wound is then bound up with strips of cloth spread with grafting wax,
and the leaf taken great care of. When the graft begins to grow, this
leaf and all the shoots below it are removed. In this manner artichokes
have been grafted on cardoons, and cauliflowers on cabbages with great
success. Tomatoes have also been grafted on potatoes in this manner,
the potatoes perfecting their tubers, and the tomatoes their fruit, at
the same time; and it is said that the ripening of the latter was much
accelerated. This mode of grafting was invented by the Baron Tschoudy,
a gentleman residing at Metz, and the principal point in it which
requires attention, is the preserving a leaf, or two leaves, at the
extremity of the stock, to serve as nurses to the graft.
[Illustration: Stock and Scion prepared for Inarching.]
_Inarching, or Grafting by Approach._--Though I have left this till
last, it is in fact the most simple of all ways of grafting, and it
is certainly the only one practised by nature. In a natural forest,
two branches rub against each other in windy weather, till the bark
of both becomes wounded; a calm ensues, and, while it lasts, the
wounded branches lying across each other adhere and grow together.
Of this, which is called inosculation, examples in the beech, the
hornbeam, and the oak, are given in Mr. Loudon’s _Arb. Brit._; and
it is probable that mankind derived the first idea of grafting from
observing instances of this kind. Inarching, as practised in nurseries,
closely resembles layering. A branch is bent and partly cut through,
and the heel thus formed is slipped into a slit made downwards in
the stock to receive it. The parts are then made to meet as exactly
as possible, and are bound together with bast mat, and covered with
grafting clay, as in common grafting. In five or six months the union
will be complete; and the inarched plant will be ready to be separated
from the parent, which is done with a very sharp knife, so as to
leave a clean cut, and not a bruised one. The head of the stock, if
it was left on when the plant was inarched, is then cut away, and the
plant is ready for removal. It is, however, customary to keep on the
grafting clay and ligature for a few weeks, till the plant is firmly
established. This mode of propagation is very commonly practised with
Camellias and Magnolias; and it is usual in nurseries to see a fine new
kind of Camellia surrounded by a sort of frame, on which are several
pots of stocks of the single red, placed at different heights for the
convenience of attaching to them different branches of the choice kind,
to undergo the process of inarching. In most of these cases the head
of the stock is retained, and the scion introduced at the side; but as
soon as the graft has taken, and has thrown out a sufficient number of
leaves to carry on the elaboration of the sap, all the branches of the
original plant above the graft are cut away to strengthen the inarched
one.
[Illustration: Mode of inarching the Camellia.]
_Grafting clay and grafting wax_ have been so frequently mentioned in
the various operations of grafting and budding, that it seems necessary
to say a few words on their composition. Common grafting clay is
made with any kind of stiff clay mixed with a fourth part of fresh
horse-dung free from litter, and a portion of cut hay; a little water
is sprinkled on the mass, and the whole is beaten several times a day
for a week together, till the ingredients are thoroughly amalgamated.
The common French grafting clay, or Onguent de Ste Fiacre, is composed
of equal parts of stiff clay and cow-dung; but a superior kind,
recommended by M. De Candolle, is composed of one pound of cow-dung,
half a pound of pitch, and half a pound of yellow wax. Grafting wax is
generally made of equal parts of turpentine, bees’-wax, and resin, with
a little tallow, melted together, and thoroughly incorporated. This is
thinly spread on cotton cloth, and used in strips like cerecloth. In
grafting trees with soft and delicate bark, fine moss and cotton wool
tied on with ligatures of bast mat, are better than anything else, and
they are quite sufficient for every purpose for which grafting clay can
be required for ladies. A new composition has been lately invented,
made with caoutchouc, which is said to be very efficacious, but I have
never seen it tried.
_The essential points to be attended to in grafting_ are choosing a
stock and a scion that correspond in nature and in habits of growth;
cutting the parts to be united so as to fit exactly and leave no
vacuity between; taking care that the soft wood of the scion shall
always rest on the soft wood of the stock, as it is between these
parts that the union is to be effected; binding the parts closely
together, and covering them so as to prevent them from becoming so dry
as to shrink apart, in which case the vessels would wither and become
incapable of uniting.
_Uses of Grafting and Budding._ The obvious use of grafting is to
propagate varieties that cannot so easily be continued by seed, and
that will not strike by cuttings. There is, however, another use nearly
as important; and this is to make plants flower and fruit sooner than
they would otherwise do. There are many plants that only flower at the
extremity of their shoots; and these plants, when tender, would require
enormous plant-houses before they would be thrown into flower or fruit.
To remedy this inconvenience, a method has been devised of cutting off
the tips of the shoots and grafting them; and then, after they have
grown for some time, cutting off the tips again and regrafting them,
by means of which flowers are at length produced on plants of quite a
small size. The same method is applied in Paris to rare fruit-trees
to throw them into fruit; and it has been tried with success with the
rose-apple (Eugenia Jambos), the mango, &c. In common nurseries, the
fruit of new seedling apples is obtained much sooner by grafting than
by leaving the plant to nature; and this plan is also practised at
Brussels by Prof. Van Mons, to test his seedling-pears.