Notes on Propagation by Seeds and Cuttings
These notes were written by Ron Stevens of the Society for Growing Australian Plants
may not be commonly available now or may have had a name change.
Part 1 – Seeds
The ripened seed has its water content almost to a minimum resulting in the suspension of its
activities. In this condition, it is able to withstand extremes of temperature which would be fatal
after it had taken up water. How long seeds retain their power of germination is not known with
certainty. Seeds can absorb moisture even from the air, so it is essential that they should be
kept under the driest conditions when stored. Seeds which have been kept in the dark and out
of contact with the atmosphere will germinate at an age impossible with seeds exposed to light
and air. Generally speaking, the longer seeds are kept, the lower will be the percentage of
germination, and less the vigour of the seedlings.
Ripened seeds are in three groups:
Group 1 – Seeds that remain on plants
Banksia, Callistemon, Calothamnus, Hakea, Leptospermum, Melaleuca, and Regelia
(exceptions are Banksia integrifolia, Callistemon viminalis, and Callistemon acuminatus).
When collecting seed pods that remain on the plant, always collect the lowest pods on the plant.
bag. Banksia cones are best held over a naked flame or placed in a hot oven. The heat will
cause the cone to open and the seeds can be collected.
Group 2 – Seeds expelled from the plant
Most of the native plants are in this group, so you must keep these plants under observation
when they set seeds. Pods may be green today and ready to open tomorrow.
Group 3 – Seeds that fall from the plant
Christmas Bush and Persoonia.
Collect seeds from these plants as soon as they change colour.
Always ensure that seeds are ripe when collecting them. Often with seeds that are expelled
few develop. Quite often they are subject to insect attacks and in some cases all the seed may
be destroyed. Gompholobiums are phone to such attacks.
Before germination can take place, seed requires moisture, air and warmth. It is necessary for
the moisture to pass through the seed coat before germination can begin.
When the seed coast is thin and soft, germination occurs readily but moisture cannot penetrate
the hard shell is damaged by decay, abrasion or fire.
So some seeds require treatment before sowing and they fall into three groups.
Among these are Acacia, Bossiaea, Brachysema, Burtonia, Cassia, Chorizema, Clianthus,
Darwinia, Davesi, Dillwynia, Gompholobium, Goodia, Gossypium, Hardenbergia, Hibiscus,
Hovea, Indigofera, Jacksonia, Kennedia, Mirbelia, Oxylobium, Pavonia, Platylobium, Pultanea,
Swainsonia, Templetonia, Viminaria, Anigozanthos (bicolour, rufa and pulcherrima).
Group 2 – Seeds requiring cover with dry leaves, setting alight and keeping alight for 5-
If possible, use soil from the area where growing for sowing. Group 2 seeds are frequently
infertile and germination may be poor. Burning may destroy some of the seeds but will crack the
hard shell of others and allow moisture to enter and the seed to germinate.
Such seeds include: some of the Boronias, Correa, Crowea, Eriostemon, Leucopogon,
Group 3 – Seeds taking up to 12 months (but sometimes only 4-6 weeks)
All of these seeds need abrasive treatment before sowing, except Eremophila which should
have the fleshy or bulbous outer layer removed and the woody case rubbed between two
sheets of coarse sand paper.
They are Conospermum, Darwinia, Eremophila, Isopogon, Micromyrtus, Myoporum, Petrophile,
Finally, some of the seeds that do not require treatment before sowing:
Boronia, Callistemon, Calothamnus, Christmas Bush, Conostylis, Everlastings, Epacris,
Eucalyptus, Hypocalmna, Isotoma, Kunzea, Leptospermum, Lobelia, Melaleuca, Melastoma,
Regelia, Sprengelia, Stylidium, Wahlenbergia, Woolsia.
In the Sydney region, I find the best time to sow seeds for quick germination is September and
October, or March and April, with Waratahs in August, Anigozanthos in September, Christmas
Bush and Actinotus in January, Everlastings and Hypocalymna in March, Brown Boronia in
Next to seeds, cuttings provide the best method of propagating large numbers of plants. They
come true from seed.
Stem cuttings are generally used and may be taken as:
Medium wood – new shoots 6-8 weeks old
Hard wood – 18 months or older
Heel cuttings – sideshoots with a heel left on them.
Cuttings should only be taken from healthy plants, never from diseased or starved plants. Some
better regeneration takes place when cuttings are taken just prior to or just after flowering. This
is the period when the sap is flowing freely within the plant and the best time to take cuttings.
They can of course be taken at any time of the year but will take longer to form roots.
With plants that are easily rooted from cuttings, age of the plant makes no difference. But age in
plants will root more easily than those from older plants.
The type of material used to make cuttings varies from plant to plant. Some are propagated
All plant growth is controlled by growth substances, some of which have the function of
controlling and stimulating root formation. A number of synthetic substances have been found
capable of stimulating root formation and now commercial preparations containing various
combinations of these synthetics and agitators are on sale: Seradix with powers for soft,
medium and hard woods, also Lanes All Purpose Hormone Cutting Powder.
In the past, it was thought that only heel cuttings or cuttings taken at a node with a clean cut just
However, with the hormone rooting powders, even internodal cuttings can be successful. Some
chances of success are greater by using them.
Plants are extremely variable in their ability to form adventitious root systems. In some, it is
The ability of a plant part to make a successful cutting depends upon the ability of cells within it
which are capable of forming adventitious or abnormal roots. This operation comes from the
cells of the cambium layer.
When a cutting is taken from a plant, the active cells form a protective tissue or callus at its
which the cells live; obviously the time this will last is limited. It also has to combat transpiration
so it is essential to get it into the propagation medium as soon as possible.
Unless the cutting is able by the formation of new roots to obtain fresh supplies of soil water and
the tissues of a cutting while it is forming new roots is of the utmost importance.
water by transpiration. To avoid the cuttings drying up and dying before rooting, two measures
are taken. Firstly, reduce the number of leaves to a minimum, leaving only the young ones. This
ensures adequate production and translocation of food and growth substance and also reduces
the leaf area from which water may be lost.
The second measure involves maintaining a high humidity around the aerial parts of the cuttings
Propagating soils and mixtures are many and varied. I use coarse washed sand for most
leaving it unwashed. Another good mixture is coarse sand and bush soil mixed 50/50, which is
good for Crowea exalata and some of the grevilleas.
Time for cuttings
Cuttings can be planted any time of the year but below are my observations of the best time of
Waratah (use soil from around plant itself)
Boronia serrulata (own soil)
Waratah (own soil)