OVERVIEW
Raising new plants from cuttings is one of the most reliable ways
of propagating. In general, the technique involves taking a small
piece of material from a living plant. After inserting into a
rooting medium, the cutting is able to produce new roots and is
then carefully nurtured until large enough to be potted on.
The main advantage of taking cuttings is that cuttings up to 1"
thick (dependant on species) can be rooted, speeding up the process
of creating a plant suitable for use as bonsai. The other advantage
with cuttings is that material that is routinely pruned from bonsai
and thrown away, can be used to create new plants.
There are a wide range of cuttings in general horticultural use
that can be used to propagate garden plants, from leaf-cuttings
to root-cuttings; for bonsai however it is stem cuttings that
are normally used. There are 3 types of stem cuttings commonly
used, softwood cuttings, semi-ripe and hardwood cuttings.
The Species Guides
at www.Bonsai4me.com list the best method and the correct timing
for taking cuttings from each species.
This gives you an idea of how to achieve good success rates when
taking cuttings, however, if material becomes available at the
'wrong time', it can still be worth trying to use it rather than
throwing it away. There may be an increased failure rate but you
may also gain a number of new plants.
SOFTWOOD/GREENWOOD CUTTINGS
Softwood are the soft, pliable shoots from the current seasons'
growth. More often than not, they will be green-wooded. These
are nearly always taken in Spring to early Summer when the new
leaves on the shoot have hardened off and changed from their Spring
colour.
Try to take these cuttings early in the morning if possible. Each
cutting should be 8-10cm (3-4") if at all possible, trim
the cutting from the host plant just below a leaf node. This is
where there are likely to be adventitious buds that will hopefully
root in the future. Cuttings that can be taken just below the
junction of a side shoot are nearly always more successful as
they have a high concentration of natural growth hormones. Trim
all leaves off the lower third of the cutting and reduce leaves
on the upper two-thirds to just 3-5 pairs at most.
SEMI-RIPE AND RIPE-WOOD CUTTINGS
Semi-ripe cuttings are generally taken in mid- or late Summer;
they consist of soft-tipped shoots of current seasons' growth
(as with softwood cuttings) but have firm and woody growth at
the base.
Ripe-wood cuttings consist of the same material as semi-ripe cuttings
but have ripened up further and are generally taken from early
Autumn to early Winter.
The cutting is taken just below a node for nodal cuttings or with
a heel of mature wood for heel cuttings.
Remove all side shoots and trim nodal cuttings to 8-10cm (3-4")
long if possible, trim heel cuttings to 5-7cm (2-3") long
if possible. Remove leaves on lower third of cuttings and for
semi-ripe cuttings also remove soft tips. Reduce large leaves
by half.
HARDWOOD CUTTINGS
Hardwood cuttings are taken in Autumn (after leaf-fall) to early
Winter. They consist of the leafless shoots of fully ripe growth
up to 1" in diameter. Trim to 15-23cm (6-9") if possible,
with the top cut just above a bud or pair of buds and the bottom
cut just below a bud or pair of buds.
ROOTING MEDIUMS
Cuttings should be dipped into rooting hormone and inserted into
a seed tray or plant pot of a standard pre-mixed cutting compost
or equal parts peat (or substitute) and perlite or sharp sand.
Ensure that the compost is kept damp at all times but do not allow
to become too wet. Cuttings' leaves should not be allowed to touch.
Watering with a fungicide solution will lessen the chances of
fungi infestation.
MAINTAINING CUTTINGS
Softwood cuttings need to be placed in a propagator to ensure
humidity levels are kept high and moisture loss is kept to a minimum.
Alternatives include placing the cuttings container in a plastic
bag or frequent misting. Softwood cuttings need to be kept at
18-24°C if at all possible. At this time of year, this usually
means placing on a bright window-sill out of direct sunlight.
Fallen leaves should be removed daily to avoid fungal growth which
can kill cuttings. As the cuttings start to grow strongly, propagator
covers or plastic bags should be removed. Softwood cuttings can
start to show signs of growth within 2 or 3 weeks, they do not
however root for far longer and should not be disturbed or repotted
until roots start to appear at the bottom of the container. It
can take as long as a year before softwood cuttings are strong
enough to be potted on individually.
Semi-ripe and ripewood cuttings should also be placed in a covered
propagator to ensure high humidity levels, though at this time
of year (Summer or early Autumn) the container is normally placed
outside where temperatures of around 21°C are ideal. Do not place
in direct, hot sun which can dry out the cuttings before they
are able to root. As with softwood cuttings, remove fallen leaves
on a daily basis and keep the compost damp but not soaking wet.
Semi-ripe and ripe-wood cuttings are normally strong enough to
be potted on the following Spring.
Hardwood cuttings should be placed outside and do not require
any cover; there are no leaves to lose moisture and humidity levels
during the Autumn and Winter are naturally high. Hardwood cuttings
require no more protection from frost than their parent plants
and only need extra protection when temperatures drop below -10°C.
Ensure that after frosts, cuttings are re-firmed into the compost
as frozen compost can lift and create air-pockets.
Hardwood cuttings will show no outward signs of growth until Spring
when tiny buds will start to appear. They can be as late to start
growing as May and until then should be left undisturbed. Hardwood
cuttings do not generally begin to root until after their first
flush of growth and unless growth is particularly vigorous should
not be repotted until the following Spring; around 15months after
being originally taken.
