New plants from cuttings
Propagating your own plants from cuttings ensures the new plants are an exact copy of the parent plant
ONE of the most satisfying aspects of gardening is, I believe, the feeling of accomplishment when you successfully grow your own plants from scratch, that is, either from seed (sexual propagation), or from vegetative pieces of other plants (asexual propagation), commonly called “cuttings”, or in slightly older gardening parlance, “grown from slips”.
One of the benefits of producing new plants from vegetative parts of another is that the resultant offspring is considered an exact copy, or clone, of the parent plant, something that can’t always be guaranteed if grown from seed.
Another benefit of growing plants from cuttings is that a great deal of money can be saved by propagating your own plants, no doubt high on the list of priorities for most gardeners.
There are a number of techniques and methods used for propagation from cuttings, and these are usually dependent on a number of variables such as the propensity of the plant to grow from cuttings, time of year, whether the plant is evergreen or deciduous, and which part of the plant will produce roots (or “strike”) readily.
Before examining the methods of taking cuttings, it’s best to think about the medium into which they will be placed, and the conditions that will promote root growth.
A good balance of air and moisture is needed for roots to be produced on cuttings. Commercial propagation mixes containing perlite, peat (coco peat or peat moss) and coarse sand (usually in the ratios of 3:2:1) are ideal for most plant cuttings. Some gardeners have had success with just coarse sand, others simply with perlite and coco peat (ratio about 7:1). Regardless of your choice, propagation media needs to be able to physically support the cutting once it’s inserted, and provide air and moisture to the point at which roots will form. You don’t need any fertiliser for cuttings to strike. Oh, and the materials must be free from disease and weed seeds of course.
You can use individual containers in the form of 50mm tubes for cuttings, or place a number in a communal pot or tray if you wish. A protected semi-shaded position in the garden is best, with the tubes, pots or trays enclosed in a plastic “tent” to maintain moisture levels. The cuttings shouldn’t touch each other or the plastic covering as it can encourage fungal disease. Even better, an enclosed greenhouse in semi-shade is a great spot for cutting production.
Evergreen, and some deciduous plants, are usually struck from cuttings taken from the growing tips. These are classified as either softwood or semi-hardwood. Softwood cuttings, usually taken in early spring, are prepared from soft, young growth of plants such as herbs (e.g. lavender, oregano, rosemary, sage), daisies (e.g. Marguerite daisies) and many softwooded perennials. Choose firm growth about 15cm in length that is quite flexible but which snaps if bent sharply. Softwood cuttings are best taken in early-mid spring, and can form new roots within two to eight weeks.
Semi-hardwood cuttings are usually taken in late spring, summer and early autumn, when the shoots have hardened, dependent on species and climate. Most evergreen shrubs and small trees are suitable, including azaleas, Murraya, grevilleas, and camellias, to name a few. Semi-hardwood cuttings usually take anywhere between six to 12 weeks to form new roots, some longer.
Hardwood cuttings are nearly always taken from deciduous plants in mid winter. Choose stems that have grown from last spring, ideally from drinking straw to pencil thickness. You can produce a number of cuttings from one shoot if it’s long enough, but cut the bottom flat and the top on an angle, as it’s easy to plant these upsidedown! Examples of plants suitable for hardwood cuttings include hydrangeas, deciduous ornamental and productive fruit trees, maples, wisterias and grapes. Hardwood cuttings can take from two to six months to form roots, so have patience!
In all cases, make a small hole with a pointed wooden stick (called a dibber!) before inserting the cutting in the propagation media, as pushing them in can damage the cutting and reduce its ability to form roots. Then firm the cutting into the mix with two fingers on either side.
Hormone powders and gels to improve root production are readily available from your local plant nursery or online specialists, as are small propagation kits, which have plastic covers and even heated mats on which to place your cuttings (bottom heat encourages root production in cuttings).
A few things to remember. If not working with them immediately, keep cutting materials moist by placing them in a tray of water, or in a plastic bag with water. Cuttings can sometimes be kept fresh for the next day by placing them in a plastic bag with some water, and in a cool (not too cold!) fridge. Only choose undamaged, disease free material. Ensure your preparation area and tools are kept clean and disinfected. Avoid using soil or old potting mix as these can introduce pests and diseases, and may inhibit root production. Finally, if taking cuttings from grafted or budded plants, their survival, once struck, may be compromised as their root system may not be suited to your soil or climate. However, you’ll never know unless you give it a go!
Happy cloning!