Propagation from cuttings
Propagation from cuttings is a vegetative method and therefore each plant produced is genetically identical to the parent plant.
Cuttings should be made as soon as possible after the plant material is collected. However, if kept cool, moist and free of fungus, some plant material can be stored for several days.
Not all species of plants can be propagated from cuttings. Cuttings taken from species of Eucalyptus do not readily form roots. This is also the case with many Acacia species and most monocotyledons, e.g. grasses.
- Collect shoot tips 8-12 cm long, preferably in the morning or evening. The plant material should be semi-mature, i.e. semi-hardwood. The best time, therefore, to take cuttings is late spring or early summer. Cuttings taken at other times will often root but may take much longer, although there are many exceptions.
- Carefully remove the leaves (and leaf stalks) from the bottom half to two-thirds of the cutting and recut the base just below a node, as shown in the diagram.
- Treat the base of the cutting with a preparation of rooting hormone. Some plant species will form roots without being treated with a hormone.
- Carefully place the cutting in a hole made with a dibble stick and gently firm the cutting medium around it. Insert the cuttings at about 1.5 to 2 cm intervals, depending on the size of the species used. The cutting medium should hold moisture but be free draining. A sterilised mixture of 5 parts vermiculite to 1 part cocopeat is ideal. Use boiled water for sterilising.
- Place the punnet containing the cuttings in a warm, humid place which receives filtered sunlight. A small propagation box can be made, as shown in Figure 2.
- Cuttings take 4-10 weeks or longer to root, depending on the species. Note: to help ensure the success of your cuttings, strict hygiene practices must be followed, i.e. working surfaces and secateurs should be sterilised with a dilute solution of bleach or methylated spirits. Pots may be washed thoroughly in water with household detergent.