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Virtual Greenhouse
> Propagation Propagation
by Brad Thompson This
article will describe the various ways
to propagate begonias through cuttings.
Rooting cuttings to form new plants is
basically a type of cloning. To make new
copies of begonia hybrids, cuttings are the
only way they can be reproduced. It’s also
an easy and quick way to make new plants of
begonia species. There are three basic types
of begonia propagation; stem cuttings, leaf
cuttings, and division.
Propagation involves taking portions of a
begonia plant and rooting them to grow into
new plants. Some types of propagation
require more skill than others or more
specialized conditions. Everyone should be
able to propagate begonias without too much
difficulty. This article contains
descriptions and illustrations of the
various types of propagation. Nearly all
begonias can be started from stem or tip
cuttings. Rexes, rhizomatous, tuberous, and
a few other types can be started from leaf
cuttings or portions of leaves. All begonias
can be divided except for some tuberous
begonias. Rooting Mediums and containers The simplest medium to root cuttings in is
water. Nearly all the types of cuttings will
root in water, except for leaf section
cuttings that require sterile conditions.
The best containers for rooting in water are
small baby food jars. Whatever container you
use should be relatively. The reason for
using a small container is that cuttings
release a rooting hormone in the water as
they root. The least amount of water, the
more concentrated the hormone. You can put
several cuttings per container. Once roots
are half an inch long, they can be potted up
in regular potting mix and grown on. Forget
any myths you’ve heard about water roots,
the cuttings will transplant just fine.
Other common mediums for rooting cuttings
are perlite and vermiculite or a combination
of both. These mediums can be used for
cuttings including ones needing sterile
conditions. Perlite and vermiculite are
rock/mineral products so contain no organic
matter that can harbor disease or promote
rotting. When using these products, you’re
basically still rooting in water. They act
as little rock sponges to hold water for the
cutting to root in. They also contain air
pockets. Perlite and vermiculite don’t
require sterilization to use, although you
do need to use distilled or sterile water to
keep it sterile. Vermiculite is less
commonly used now, I believe it was
determined to contain asbestos. When using
either product, you should wear a mask or
avoid breathing in the dust when mixing or
pouring it.
Another medium for rooting is peat moss or
various combos of peat moss, perlite, and
vermiculite. This works for all types of
cuttings but unless sterilized for sure, it
may rot cuttings since it contains organic
material. It is mostly used for stem
cuttings or rhizome cuttings that don’t
require sterile or specialized conditions.
It’s also used for cuttings that are overly
fleshy and tend to rot in water only.
Many begonia cuttings can be started
directly in your potting mix in a shady
location. Most rhizome, shrub, thick-stemmed
and canes will start directly in mix. You
should only use this method for the sturdier
varieties though.
There are many clear containers such as
sweater boxes that work quite well for
rooting begonia cuttings. Leaf and wedge
cuttings require some type of container to
root in. It has two benefits. It keeps the
humidity up so the rooting medium doesn’t
dry out and is less stress on the cuttings.
It also keeps spores that cause disease from
your medium.
Tip and Stem Cuttings
 A tip cutting has to have certain elements
in order to grow a good plant from it. As a
general rule, begonias won’t send out new
growth from a node where they have
previously had a bloom. Nearly all begonias
that won’t grow from leaves also won’t send
out growth from a node they bloomed at. This
element doesn’t apply to tuberous,
rhizomatous and rexes, they will send out
new growth from any rooted part of the
plant.
The illustration at the left shows a typical
begonia stem and its various possible
components. On a begonia stem, there is a
node above each leaf. This node can have a
bud that will grow into a new stem someday,
it can have a flower cluster grow from it,
or it can be dormant and not showing a bud.
Any node that doesn’t have flowers or the
scar left after the flowers have fallen off,
has a bud in that node whether it shows or
is completely dormant and not showing in the lowest node will be a good cutting.
A good cutting needs to have a node with a
bud on it for it to grow into a proper plant
after it’s rooted and In the illustration
you can see that the planted. The bud is
where all future basal growth will lowest
node pictured has a scar from where come
from as the cutting grows. Using cuttings
where the leaf was attached. It also has a
bud. the nodes have had blooms will result
in plants that can That is the main
requirement of a good never send up new
basal growth. The illustration cutting, no
matter what the rest of the shows how to
determine what nodes you have. If you nodes
on the cutting, look at a node and there
is a leaf or the scar left after a leaf has
fallen off, and there is no scar left from a
.A tip cutting should also have at least a
flower, then there is a growth bud there
whether you couple leaves. One without
leaves may can see it or not. When leaves
and flowers fall off they root but not as
easily or as quickly. You both leave round
scars on the stem where they were. can also
make a regular stem cutting from So, a bare
node that has two scars is a node that parts
of a stem that don’t have the tip. For
previously had a leaf and a flower cluster.
If this those types of cuttings, since they
don’t explanation isn’t clear, the
illustration on this and the have the tip,
need to have at least two next page should
make it clearer for you. One
at the base of the
cutting that will be buried in the potting
The best cuttings are ones that have never
bloomed mix and one to grow into top growth.
It since they have buds in all their nodes
that will should also have a leaf if
possible. Woody eventually grow into new
stems and new side growth. hardened stems
will root without leaves Any stem cutting
though, that has at least one good bud
however. They do take longer though.
The illustration at the right shows a good
tip cutting. Elements of a good tip cutting
It has buds in the leaf nodes for future
stem growth as described previously. When
taking a tip or stem cutting cut the stem
about half an inch below the selected node.
It’s possible that if you have any stem rot
while rooting the cutting, if you have cut
closer than half an inch below, you could
lose that lower node. Half an inch gives you
some margin. Cutting further than half an
inch below leaves too much unnecessary stem
below the lowest bud. When you get ready to
pot up the cutting after it roots, it will
be hard to get that lowest bud buried in the
potting mix if too much extra stem is left
below it. When rooting the cutting, you
should remove any leaves from the lower
nodes first, since those parts will be
buried eventually anyway can could rot.
In the illustration below right you can see
how to pot up the newly rooted cutting. Put
the cutting as low in the pot as possible
covering at least one good bud. In the
illustration, you can see the importance for
doing this. The buried buds will eventually
grow into new shoots and all the future
basal growth. Without a buried bud, the
cutting will of course still root and grow.
It won’t be able to send up new basal growth
however. It will only be able to branch
somewhere above the pot.
The only time you should use cuttings
without buds to bury is if you’re going to
grow a begonia as a standard. Since a
standard should be just one main stem,
ordinarily bad cuttings are perfect for that
purpose.
For begonias that are everblooming and hard
to get good cuttings from, one tip is to
first prune the plant. Then take cuttings
from the new growth comes up. Rhizome Cuttings Rhizome cuttings are a type of stem cutting.
Unlike cane, shrub and other stem cuttings
however, you don’t have to worry about nodes
or bloom scars. Rhizome cuttings can be made
any length. In the illustration above the
rhizome is cut into two inch sections. Most
rhizomes can be rooted directly into your
potting mix without any special
considerations. The rhizome is fleshy and
can easily maintain itself until roots and
leaves form. Some more delicate varieties
such as rexes may do better if rooted in an
enclosed container though. Long rhizomes can
even be rooted in water like you would any
stem cutting. They are slightly more prone
to rotting in water though since they are so
fleshy. Although leaf cuttings on
rhizomatous types will give you more plants
in the long run, rhizome cuttings will give
you a new plant faster. It’s a good method
for those that just want another plant or
two and aren’t worried about producing
larger numbers of plants. The rhizomes don’t
have to have leaves to root and grow. When
using the tips of rhizomes remove the
largest leaves, they’ll probably fall off
during rooting anyway. Make sure the rhizome
has good contact with the rooting medium but
not buried more than half way. Tip cuttings
from rhizomes can be rooted upright with the
cut end stuck one half to one inch into the
rooting medium. Leaf and Wedge cuttings Many types of begonias will start from leaf
cuttings. These are mainly rhizomatous,
rexes, and tuberous begonias. With nearly
all begonias you can root a leaf, but only
certain types will then send up a new plant
from the rooted leaf. With begonias other
than the three types mentioned, consult with
other growers about specific plants that may
start from a leaf. Exceptions to the only
rhizomatous and tuberous starting from
leaves rule, are begonias such as B. luxurians and some of the mallet type canes. Types of leaf cuttings All parts of the leaf are capable of rooting
and forming a new plant. The only
requirement is that the leaf portion contain
a main vein. There are three main types of
leaf cuttings. A full leaf cutting, wedge
cuttings, and cone cuttings. If your purpose
is to create a number of plants, you may
choose to do wedge cuttings since you can
make many wedges from a single leaf. If your
purpose is just to propagate a couple of new
plants for yourself, you may choose to just
use whole leaf cuttings. Cone cuttings are
slower than regular whole leaf cuttings but
since more veins are exposed to the rooting
medium, the resulting plant is much fuller.
Materials required
There are several basic requirements needed
for starting leaf cuttings. You need warmth,
good light, humidity, and a sterile moist
medium.
Light and warmth
This is best provided by using fluorescent
lights. A light stand, besides providing
constant good light, also provides suitable
warmth. Any area you can keep reasonably
warm will work however. If not using lights,
you need an area with bright light but no
sun. Since leaves need to be rooted in
covered containers, any sun will overheat
and cook the cuttings. Under lights, you can
keep the lights as close to the top of the
container as possible. Leave the lights on
for at least 14 hours a day. You can leave
them on continuously if desired. Containers Most leaf cuttings need covered containers
to root in. The purpose is to keep the
humidity high and also to keep the medium
sterile. The container can be as simple as a
clear plastic cup covered with saran wrap
for single cuttings or an expensive tray
with a clear dome. You can even root leaf
cuttings in zip lock bags. If you’re lucky
enough to have a greenhouse, you can root
leaf cuttings out in the open under a
misting system. Even in a greenhouse though,
you may choose to use covered containers for
ease of use.
I know several growers that root in zip lock
bags with individual bags for each cutting.
One grower I know stapled the bags to the
wall in out of way places during warm
weather. For especially rare or hard to grow
varieties, I usually do provide those
cuttings their own container. I put the
rooting medium in a small pot then put the
pot into a zip lock bag after the cutting is
in it.
Trays with domes or clear sweater boxes work
very well. You can even use aquariums left
over from your fish experiments. There are
also a myriad of different clear sandwich or
food containers to choose from.
You can either use the medium directly in
the tray or use individual pots of medium
for each cutting then set in the tray. Both
have advantages and disadvantages. Just
filling the tray with medium is easier and
can be refilled over and over. However, in
my experience if you root this way you end
up with parts of the tray and different
varieties of begonias growing at different
rates. You usually end up with half of the
tray potted up already and the rest still
waiting. If you propagate continuous and
keep refilling the tray as you take things
out, it will work fine though. Another
disadvantage is getting or keeping the
medium to the correct dampness without being
too wet. It’s also hard to keep the cuttings
separated by variety as they grow unless
you’re careful to make clear separations and
labeling.
Using individual small pots for each cutting
works well because you can move cuttings
from box to box as needed. If you’re using
several boxes as things get potted up, you
can recombine the slower rooting cuttings
into one box. The disadvantage is that it is
more time consuming filling all the
individual pots and making separate labels
for each. If you don’t mind the added time,
it’s the better method though. Rooting mediums for leaf cuttings The most commonly used medium for leaf
cuttings is perlite. It is already sterile
and holds the correct moisture without
staying too wet. Its only disadvantage is
you have to check often to make sure it
doesn’t dry out. Any medium such as peat
moss, vermiculite and combos will work fine
as long as they are made or kept sterile and
kept to the right degree of moisture. I have
used all the various mediums with good
success but find perlite the easiest and
best to use.
Another less common medium for rooting
cuttings is called Oasis(TM). This is
similar to the Oasis used for floral
arranging but comes in form specifically for
rooting cuttings in. It is made a size to
fit the most common tray size. It has
individual one inch cubes with a hole in the
center of each to insert the cutting in. The
Oasis can be cut easily to fit any container
though. Don’t try using the floral Oasis for
this purpose, it isn’t made for rooting
cuttings like this other product is. The
oasis is soaked in water till it has soaked
up as much water as it can, then drained. It
already contains fertilizer so nothing needs
to be added to the water. It’s already
sterile so also doesn’t need to have
anything extra done to sterilize it. I have
used it successfully many times and it works
especially well for wedge and small
cuttings. It was designed so that after the
cuttings are rooted you cut the cubes apart
and plant the cube and all in your potting
mix. This design however doesn’t work for
begonias. If the cube is left on the cutting
the plant will usually not thrive or die
later. The cube either wicks water to the
surface of the mix so causes a dry spot, or
stays too wet and causes the plant to rot
later. Examination of the roots on plants
that failed showed that the roots all stayed
in the oasis instead of growing out of it
into the mix. For this reason, you must
remove all the Oasis from the rooted cutting
before potting them up. This usually results
in some root loss, besides being time
consuming. However it is easy to use so does
have its uses for some growers. Other items you’ll need One item you’ll need is something to cut the
leaves with. You can use a knife, scissors,
or pruners. The best cutting tool to use is
a razor blade. There are several reasons.
Using a new blade means you have a sterile
utensil that doesn’t have diseases from your
plants outside. If you use your pruners,
you’d have to sterilize them. The main
reason though is because it makes a very
clean precise cut. If you use scissors or
pruners they don’t cut cleanly and crush the
edges of the cutting. This makes the cutting
less able to draw up water. Using the razor
blade cuts cleanly without crushing cells
along the edge.
You’ll also need something to sterilize the
cuttings with. It doesn’t matter how sterile
your medium is if the cuttings you put into
have spores of disease on the leaf surface.
The most common disinfectant for using on
cuttings is a five percent bleach solution.
I have also heard of using a peroxide
solution but haven’t personally tried that.
I have also sterilized cuttings by dipping
them in a fungicide mixed to the recommended
strength on the bottle. I let them dry, then
rinse with water before using. Make sure to
wear gloves. You can also use Physan(TM)
following the directions on the bottle. I
usually spray my tray of cuttings with a
fungicide after they are done just to make
sure nothing was missed. Whole Leaf Cuttings A whole leaf cutting consists of a leaf with
a portion of the leaf petiole (a petiole is
the stem-like structure that holds a leaf to
the plant stem). You should leave the
petiole about one half to one inch long for
rooting. When taking the cuttings leave the
petiole long until just before you’re ready
to put it in the medium so that the cut is
fresh. Leaving the petiole too long won’t
hurt anything. However, it will take longer
for the plantlets to come up after rooting
since they’ll have to come up from deeper in
the medium.
In the illustration on this page you can see
a whole leaf. The best leaf cuttings are
young leaves but any leaf will work such as
damaged leaves you have to remove anyway. If
the leaf is small you can just cut the
petiole and insert it into the rooting
medium. Larger or damaged leaves you should
cut down as in the illustration leaving a
round center of the leaf with the petiole.
The remaining part of the leaf can be
discarded or used for wedges. The reasons
for cutting the leaf down is that it takes
up less space in the tray and because the
petiole will have less leaf to support. The
cut down leaf will have less leaf surface to
transpire from so the petiole won’t have to
provide so much water. Even if making wedges
or cone cuttings, save that middle portion
as an extra cutting. On difficult varieties,
that portion will usually root, even if your
wedges fail.
Whole leaf cuttings can be started without
enclosed containers for some of the sturdier
varieties. You can leave the petiole
slightly longer and root them in small jars
of water. You can also fill the small jar
with perlite and add water. The second
method does support the leaf better. You can
also use pots of perlite set in a shallow
tray of water. If you use any of these
methods, don’t cover the container since the
cuttings will usually rot with all that
water if covered. It does take practice and
experience to find out which varieties of
begonias will work with which methods.
Wedge Cuttings
Wedge cuttings are the easiest way to start
many plants at a time with the least plant
material. It’s especially useful for rare
begonias or begonias that only have a couple
good leaves to use. In the illustration you
can see how to cut a leaf into wedges. A
wedge is simply a portion of leaf with a
vein in it. You can make your wedges as
small or as large as you like. Smaller
wedges may not survive if your conditions
are less than perfect. I usually make my
wedges about an inch or inch and a half
long.
For wedges, conditions must be as sterile as
possible. As stated earlier in this chapter,
a razor blade is the best utensil to use for
cutting. Perlite is the best medium for
rooting wedges. Add a very slight amount of
fertilizer so the plantlets have some food
when they start to grow. You can fill a tray
with perlite and premoisten. When perlite is
wet it becomes very solid. I use a knife or
plant label to make rows of small slits in
the perlite the right size to fit my wedges.
The wedges can be touching or overlapping so
don’t be afraid to pack them closely.
Usually about half an inch to and inch apart
works well. Try to insert the wedge
as upright as possible. Also make sure to
label carefully and keep different varieties
separated. Try to mix the tray up so that
varieties that aren’t a similar color aren’t
next to each other so they don’t get
confused later. They do require a covered
container.
Wedges may take a couple months to form
roots and plantlets. Check the moisture of
the medium regularly to make sure it doesn’t
dry out. Misting occasionally with a weak
fertilizer for foliar feeding will help them
along. You may want to leave the cover
opened slightly till they dry off a little
before closing tightly. Using distilled
water will make sure that you don’t
introduce any diseases into your sterile
environment.
As soon as little plantlets have come up and
are large enough to handle they can be
potted up individually into small pots. The
illustration at the top of this pages shows
the new plantlets coming up from a leaf
cutting and wedge cutting. For the first
transplant they should remain in a covered
container. Treat them as you would seedlings
of the same size. Once they have filled the
small pot and are ready to transplant again,
you can harden them off and move to other
locations. Cone Cuttings Cone cuttings are similar to wedge cuttings.
You cut the center portion out of the leaf
but instead of cutting it into sections, you
leaf it whole. You wind it around to form a
cone and insert i nto your rooting medium.
Make sure to also put some medium inside the
cone. On the next page are illustrations
showing how to do this.
The advantage to cone cuttings is the full
plants you can get from this type cutting.
Plantlets will come up from all the vein
ends along the bottom of the cone resulting
in dozens of shoots. If left together, they
quickly grow into one full plant. They can
also be separated or cut apart to make many
smaller plants after rooted and plantlets
have formed.
On all the various leaf cuttings discussed
in this chapter after plantlets have formed
you can either pot up the cutting along with
the plantlet or you can remove the plantlet
and use the cutting over again. Some
cuttings will send up plantlets several
times before they run out of energy if
reused. Mallet and Heel Cuttings
These types of cuttings are not commonly
used but they do have purposes. There isn’t
much difference between the two and the
mallet has less chance of errors or rotting
so you shouldn’t use the heel version unless
you have a specific purpose.
A mallet cutting will allow you to make a
type of leaf cutting from plants that
ordinarily won’t start from leaves. Since
the leaf cutting contains a portion of the
stem with a growth bud it can be used for
any type of begonia. It’s mostly useful for
creating as many plants as possible of a
certain variety. Say you have a cane with
one stem that has several nodes with good
buds. If you propagate by stem cuttings you
might only get one or two cuttings. By using
mallet cuttings you may get a dozen,
depending on how many nodes and leaves there
were. V arieties of canes that drop their
leaves easily may not be good candidates
because the leaf may separate from the stem
before the mallet roots. Treat mallet
cuttings as you would whole leaf cuttings
following the same procedures. After rooting
a shoot will grow from the bud on the
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