Salvia divinorum is a relatively easy plant to propagate from cuttings. Small cuttings will usually root within two or three weeks. Cuttings seem to root best when they are between two and eight inches long. They should be cut off of the mother plant using sharp, clean shears. The cut should be made just below a node.
To root the cuttings in water: Put each cutting into a glass of water. Each glass should be filled about 4 -5 cm (1 1/2 – 2″) deep. It is a good idea to use a separate glass for each cutting so that if one starts to rot it doesn’t spoil the water and kill the others. Leave the glasses indoors in diffuse light and add a little water as necessary to maintain the water level. In about two weeks you should see some roots starting to form. Some cuttings may root more quickly than others. I find that they root just fine in plain water and no rooting hormones are necessary.
When the cuttings have several roots 1 – 2 cm (1/4 – 3/4″)long, they should be planted in pots of loose potting soil and watered well so that the soil is completely moist. Keep them indoors for another two or three weeks so that they can establish a good root system in the pots with out having to deal with the wind and big temperature swings of the outdoors. You will need to keep the plants in a moist environment for a few days after moving them from the water to the pots to keep them from wilting. The easiest thing to do is to just cover the whole plant with a large upside down jar or use a big plastic bag with a wire cage support to keep it from collapsing on the plant. Spraying them with a fine mist occasionally is also a good idea. Don’t wait too long to move the cuttings from the water to soil. If you do the roots will be more prone to damage and the cuttings will begin to starve for nutrients.