The Tribune

By Gardener Jack Plants use many means of propagation. Although most plants regenerate from seeds there are plants that grow from bulbs, tubers, rhizomes, and corms. The leaf of life develops small rooted plants along the edges of its leaves and drops them to start an independent existence. The banyan drops roots from its branches from which new growth develops and you can end up with a banyan forest consisting of one tree. Woody plants can also be propagated from cuttings, a section of a limb that is cut off and planted independent of the parent. When plants are grown from seeds there may be variations but a cutting is identical to the parent plant. The reason why cuttings work is the existence of growth nodes along the limbs of plants. These growth nodes are the points at which branches and leaves develop when above ground, but if cut away and planted the same nodes produce roots below ground. Cuttings are best made from limbs growing close to the ground that have bark and are between half an inch and one inch in diameter. Limbs further from the ground often do not have bark at the flowering end and should not be used for cuttings. They can be propagated but this usually requires a mist bed. A cutting must be removed from the parent plant so there is a growth node just above the cut. There is no need for a cutting to be very long and I find about ten inches is a handy size. Much longer than this then the cutting will be affected by the wind and the root end moved around, preventing root formation. I like to trim the lower end of a cutting at a 45-degree angle half an inch below a node and cut the top end straight, just above a node. Although the sharp end looks handy for pushing into the ground this is a bad idea. Dig a hole to loosen and aerate the soil and fill it back in around the end of the cutting. Any branches on the cutting should be cut away flush with the surface. If there is any budding, or leaf growth that is less than an inch long, you may choose to leave it as it will encourage root growth. Any large leaves will act as sails for the wind and move the cutting fractionally. You can plant your cutting in a pot or place it in the ground where you want it to grow. Watering should be minimal to keep the soil barely moist. Too much water can cause a cutting to rot. The length of time it takes for roots to develop depends upon the individual type of plant. Softwood shrubs such as hibiscus and croton develop roots within a month. Hardwood plants like bougainvillea may take two months for initial root growth. Allow at least three months - more is better - before transplanting a potted cutting. Some cuttings benefit from sitting in water to establish initial root growth. I find this particularly useful with thunbergia, or Blue Sky Vine. The water should be changed at least every week and once roots appear you can add a pinch of very mild soluble fertilizer, such as orchid fertilizer. Do not let the roots get too bushy before transplanting as it will then be difficult to seat the roots in the soil. There are always exceptions to any rule and the Mombins - scarlet plum and hog plum demonstrate this. Their cuttings should be whole branches taken from the tree while bearing fruit. Small fruit trees can be propagated by cuttings but I would advise against this under normal circumstances. Fruit trees develop taproots when grown from seed but the cuttings do not develop taproots. This makes them vulnerable to high winds. Cuttings, once established, flower early and reach adult height quickly. One parent hibiscus shrub can produce (with your help) a hedge a hundred feet long within a year or two.