Oleanders flourish when propagated through stem cuttings. If you have a particularly beautiful, healthy oleander plant, you can create a "clone" of the original plant using this technique. There are a few different stem cutting techniques, but the one used for oleanders is called "semi-hardwood cutting." This method involves using relatively young stems from an already established plant and combining it with rooting hormone, which you can buy from garden centers, home improvement stores and hardware stores, to create a new plant.
Sterilize your pruning clippers by dipping them in a solution of diluted bleach or rubbing alcohol. Allow them to dry before taking your stem cutting.
Locate some relatively new growth that looks lush and healthy. Look for stems that are firm, but not brittle, and have fully mature foliage. Measure a stem that is about 6 to 8 inches long and cut it from the plant with the sterilized clippers. Wrap the cut end in a damp paper towel and set it aside.
Fill a planting pot with a mixture of equal parts perlite and peat moss. This planting medium will allow for good drainage and aeration, both of which are vital to propagation with stem cuttings. Water the planting medium thoroughly.
Remove all of the leaves from the lower 4 inches of the cutting. Dip the cut end of the cutting into rooting hormone and push it into the perlite mixture to a depth of about 2 or 3 inches. Press the mixture in around the cutting so that it is secure and stands upright.
Wrap the entire container in a clear plastic bag. This will create a greenhouse-like effect, which will help the rooting process along. Water the plant with a spray bottle as necessary to keep the planting medium moist. After about one week, grasp the cutting by the base and lift very gently. If the plant resists, roots have grown and settled into the soil. If the plant does not resist, wait another week before checking again. Remove the bag once the cutting has rooted itself.