|What is the best method of propagating Oleander stem cuttings: soil mix, conditions, temperature, etc.?|
First of all, all parts of Oleander (Nerium oleander) are poisonous if ingested. Also, severe skin irritation is possible, so use caution when working with the plant
Oleanders aren't terribly fussy. Root about 3 inches of greenwood or semi-ripe cuttings in pots in a humid environment. Bottom heat ranging from 54-68 F will speed the rooting process, which takes 3-6 weeks. Cuttings will also root in water.
Semi-ripe cuttings are taken in late spring to early autumn from the current season's growth that has begun to firm. The cutting's base should be quite hard, while the tip should be growing and still soft. Greenwood cuttings are of new growth that is not yet firm.
Remove side shoots. Make a shallow wound on the stem by cutting away a thin piece of bark (1/2 inch long). This stimulates rooting. Dip in a rooting hormones and insert in a soilless potting mix.