You can easily propagate many plants from cuttings. Basil, mint or lemon balm, or houseplants, such as begonias, geraniums or violets, all can be easily rooted in water. Cut a piece with several inches of stem, place it in a jar of water, add about a teaspoon of potting soil and place the jar in a bright window.
Instead of potting soil, I have also used the new growth from willow branches to start plants (willow bark contains natural rooting chemicals). To do this, prune the new growth off your willow (2 or 3 inches), snip it into small pieces, crush the pieces and add these to your water. Using a clear glass jar or vase for this is a good idea, so you can make sure your stem is developing roots. As soon as you see roots, you can place the stem into potting soil.
For certain plants, such as cyclamen, ferns and palms, it’s best to divide a start from the mother plant rather than rooting a cutting. To do so, carefully separate an entire stem with roots from the mother plant and put it directly into potting soil.