Propagating lavender is the easiest way to add to your stock of plants, and the most reliable as growing lavender from seed is notoriously difficult. With a few simple steps you can be well on your way to adding new plants into your landscape: first, take your cuttings from your existing lavender plants after the blooms have begun to fade, but early enough that your new plantings will have sufficient time to establish a strong root structure before the temperatures get too cold and the plants go dormant – this is usually in mid to late summer.
Deciding where to cut on your existing lavender plant is important. Moving down from the top of the branch go past the flowering spike and then count down 4 leaf groupings. Cut the branch under the 4th leaf grouping. By having 4 distinct sets of leaf groupings you will be able to plant 2 below the surface in your soil medium, leaving 2 above the surface to encourage healthy growth
immediately after removing the cutting from the mature plant, store them in moist growing material in order to protect the open cut area. Store them in a shady outside location until ready for planting. Once your stored cuttings begin to establish roots that are about 1” long, transplant them to traditional pots with potting soil.
Young cuttings need more water than mature plants, but it can be a delicate balance. If you begin to see blacked leaves at the base of the plant you need to cut back on the amount of water than your new lavender plants are getting.
Finally, once your new lavender plants have an establish root system that binds the potting soil together in the small pot, do the final transplant into their permanent home in your landscape.