Agriculture Reference
In-Depth Information
11
Figure 11.9
Air layering on tree
Serpentine layering
is essentially the same as simple
layering but several new plants are created from each
shoot, that is, wounded, pegged down and covered
in more than one place. Care needs to be taken to
ensure that there is at least one bud exposed and one
bud covered with soil for each section. This method
works well for vine-type species such as
Vitis
spp.
(grape)
and
Clematis
spp.
French layering
is another variation on the
theme which yields yet more new plants, but
success tends to be limited to vigorous specimens
such as
Cornus
spp.
This method depends on
pegging down stems on the soil surface which,
by the following spring, have new stems growing
upwards along their length. Mounds of soil crumbs
can then be placed at the base of each new stem to
encourage rooting at the node (junction) and treat as
for serpentine layering.
Air layering
can be used when the stem of the
subject such as
Ficus elastica
(Rubber plant) which,
despite its name, is not flexible enough to bend down
to the soil. This is usually done in the spring. The
main stem or a branch (at least of pencil thickness)
can be
wounded
. This area is wrapped with moist
vermiculite which is kept moist and held in place with
polythene secured with twist ties or similar; more
details are given on the companion website. This
method is often used for many hardy plants because
they are particularly difficult to root by other means
(Figure 11.9).
Figure 11.10
Rooted cutting
X
where to make the cuts (e.g. below a node or
internodal)
X
which composts to use (e.g. neutral or ericaceous
see p. 181)
X
the environment for the different stages (e.g.
temperature, humidity)
X
the use of rooting hormones or not.
Cuttings are taken from juvenile growth and with
vascular cambium (see p. 79) that gives rise to
adventitious ('wound' roots). Only healthy parent plants
should be used and the hygienic use of knives, compost
and containers is strongly recommended (see p. 194).
Rooting is usually more reliable from younger plants
and when taken when the parent plant is turgid. In
general, rooting is more successful when cuttings are
provided with 'bottom heat' but when their aerial parts
are kept cool to reduce foliage growth and water loss.
These special conditions ('cool top, warm bottom') are
provided by propagation benches in a greenhouse or
heated propagators (see Figure 11.4).
Stem cuttings
can be taken from stems that have
attained different stages of maturity: softwood, semi-
ripe or hardwood.
Softwood cuttings
are taken in spring from stems
before there is any woodiness. They are used for
the propagation of a wide range of species such
as
Fuchsia
,
Pelargonium
and
Chrysanthemum
(Figure 11.10). This material is very vulnerable to
drying out so collect from well-watered parent
Cuttings
Cuttings
are parts of plants that have been carefully
removed from the parent plant and used to produce
a new plant. Different methods may be needed for
different species. Factors to consider are:
