Answer: Grevillea lanigera (Wooly Grevillea) can be successfully propagated by cuttings. Cuttings should be taken from firm, current season's growth. Both hard, woody material and soft, 'floppy' growth are likely to be unsuccessful. The suitability of the material can be tested by bending the stem through 60 - 90 degrees. If it springs back to its original position, it's suitable, but if it breaks or remains limp, it's best avoided. Sometimes, however, the only material available will be less than ideal and it shouldn't be rejected because of this. Successful cuttings can sometimes occur from the most unlikely looking material. Cuttings can be taken at any time of year but root formation is very slow in the colder months.
You'll need a clean, sharp knife or blade and a "cold frame" to maintain a humid environment while roots are developing. You can make a simple cold frame by just tying a plastic bag around a pot of cuttings. For larger quantities a small frame could be built.
Cuttings can be placed into individual small pots or a number of cuttings of the same species can be placed into a single "community" pot. A potting mix consisting of 75-80% washed river sand and 20 - 25% artificial peat moss has been found to be suitable as a general purpose mix for cuttings. Cuttings are generally 4-6 inches long although this will vary depending on the physical size of the stem and leaves of the plant.
If the material is suitable, two or three cuttings can be made from the same piece of stem. The lower end of the cutting is usually cut directly below a leaf/stem junction (a node). The bottom half to two thirds of the leaves are stripped off if this can be done without tearing the bark otherwise the leaves are carefully cut off.
Dip the cut end in rooting hormone and set it in the potting mix. It's preferable that cuttings not be pushed into the potting mix. A hole can be prepared for each cutting using a skewer or something similar, and each cutting should be placed so that it touches the bottom of the hole. The potting mix should then be firmed around it. After all cuttings have been 'set' they need to be watered and placed in the propagating frame in a shaded place. The frame should be kept closed to maintain humidity.
Most cuttings will 'strike' (ie form roots) in 4-8 weeks in warm weather. Some species, however, may take much longer...up to 12 months or more in certain cases. If a cutting remains green and healthy it can be left in the frame for as long as needed (or until the propagator runs out of patience!).
Roots may appear through the drainage holes in the pots or root development may be checked by gently tapping out the soil mass from the pots.
Hope these pointers help you successfully propagate your wooly grevillea!
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