The most common way to grow new plants is to sow seeds, but many plants also can be propagated vegetatively by rooting tip cuttings or stems, or dividing clumps. If you already have a healthy plant, vegetative propagation is often faster, easier and cheaper than growing more plants from seeds. It takes six weeks to grow a tomato seedling to transplanting size, but you can root a stem tip cutting in half that time. In five minutes, you can multiply one petunia or coleus into several happy plants, and it will cost you nothing to start a new planting of grapes by sticking pruned branches into a bed of moist soil. This also works well with other types of plants. No special equipment is needed to become an accomplished plant propagator, though it helps to carry a spirit of adventure into each new project, because each species responds differently to various techniques, and propagation often involves a serious injury or near-death event followed by recovery. Plants that are easy to propagate know how to handle this unnatural disaster. Green Intelligence If you were being chased by someone with a knife or about to be trampled by a herd of buffalo, you would run away or hide. Plants cannot, so they have devised fundamental ways to survive common catastrophes. On a cellular level, most plants stock their stems with “undifferentiated” cells that begin multiplying into specialized cells if the plant “decides” that its best shot at survival requires new stems, leaves or roots. These undifferentiated cells are most numerous in nodes, the places where branches and buds emerge from stems and in buds that form on shallow roots and low-growing stems. Your job, as a propagator, is to identify where the plant is holding its caches of undifferentiated cells, and then provide perfect conditions to help those cells morph into beautiful new roots. To get an introductory look at this process, start with a sprig of supermarket mint. Clip or pinch the lowest leaves from a 4-inch-long stem, stick it in a small water-filled glass or bottle for 10 days, and you should see the beginnings of tiny white roots emerging from the nodes and the sections of the stem between them. You can transplant the cutting to a pot as soon as the roots are a half inch long.