A versatile, long-blooming and low-maintenance shrub, oleander (Nerium oleander) can be propagated from both cuttings and seeds. Growing outdoors year-round in U.S. Department of Agriculture plant hardiness zones 8 through 10, oleander also grows well as a container plant in all zones providing it's overwintered in a frost-free area. Oleander cultivars range from compact shrubs that grow 2 to 4 feet tall to 9- to 20-foot-tall varieties, and bear white, pink or purple single or double flowers. All oleander plant parts are extremely poisonous and oleander sap is an irritant for some people, so wear gloves when handling this evergreen shrub and don't grow it in areas accessible to children or pets.
Propagating From Cuttings
Disinfect pruning shears by wiping the blades with rubbing alcohol and put on gloves before taking cuttings from oleander in late summer. Prune 6 inches of thin hardwood stems or shoot tips, cutting just above a leaf node.
Prune the leaves from the lower half of the oleander cuttings and prune the upper leaves to 1 inch long. Wash the pruning shears thoroughly after use to remove all traces of sap and plant debris.
Place the oleander cuttings in a glass jar or similar container and add sufficient water to submerge the leafless portion.
Add water as needed to maintain the original depth in the container and replace the water if it turns cloudy or smells offensive.
Remove the oleander cuttings from the water when roots have formed and grown 1 to 2 inches long. Plant each cutting in a 3-inch plant pot with drainage holes in free-draining potting soil, such as a mix of equal parts peat and sand. Place the plant pots on a sunny windowsill or other bright, frost-free spot.
Water oleander cuttings regularly so that the potting soil remains constantly moist but never sodden. Transplant cuttings into plant pots that are 1 inch larger when their roots fill their pots. Oleander cuttings are ready for planting outside in frost-free areas when their roots fill 1-gallon pots.
Propagating From Seed
Put on gloves and fill 3-inch plant pots with a free-draining potting soil, such as an equal mixture of peat moss and sand, in spring. Spread oleander seeds evenly on the surface so that the seeds are about 1 inch apart. Firm the seeds lightly into the soil with your fingertips or sprinkle a fine layer of potting soil over them.
Water the oleander seeds with tap water, using a fine-rose watering can until water appears through the drainage holes of the containers. Place the plant pots in a bright, sunny site, such as a frost-free home greenhouse or sunny windowsill.
Mist the surface of the potting soil with a fine mist spray and tap water whenever the soil dries out.
Put on gloves and transplant oleander seedlings when the second set of leaves appears. Remove seedlings gently from the plant pots and plant each seedling in a single 3-inch pot. Water the seedlings when the surface of the potting soil dries out.