Propagating shrubs from cuttings gives you an exact genetic replica of the parent shrub. For expensive, or rare, shrubs, taking cuttings is an inexpensive way of getting more from that particular shrub. Some shrubs will spontaneously form variegated foliage, odd-shaped leaves or another anomaly on a particular branch. Taking cuttings from that branch allows you to propagate a new form of an old favourite.
When to take cuttings
When to take a cutting from a shrub depends on where you live and the type of shrub you are trying to propagate. Don't take cuttings, called mature stem cuttings, from shrubs that are in full bloom or setting fruit, as all their energy is going into these activities rather than making cells for new vegetation. Mature stem cuttings are incredibly hard to root. For the most part, taking cuttings in mid- to late spring or early summer will net you young growth, called softwood cuttings, that are easy to root. For shrubs that bloom during that time, prune back some of the branches after they have stopped blooming. Most of the time this will generate a new flush of growth that will provide softwood cuttings. You can take cuttings of evergreen shrubs like boxwood, yew and privet at any time, except when the plant is dormant (late autumn through late winter). You can take cuttings as late as early autumn before the shrub goes dormant. These cuttings are called greenwood or semi-ripewood cuttings. They are more difficult to root, take longer to form roots and will need to remain indoors until the following spring. You can also take cuttings from dormant shrubs, which are called hardwood cuttings. Hardwood cuttings are typically grafted onto a rootstock that changes the size or shape of the mature shrub.
How to take a stem cutting
Use a sharp knife or pruning shears to make the cuts. Disinfect your cutting instrument between cuts and between shrubs to prevent the spread of disease. Your cutting should be at least 15 cm (6 inches) long and include several nodes (the spots where leaves emerge from the branch). Take the cutting from the end of healthy branches and cut above a node on an angle. Trim off all but the top three to four leaves. If the remaining leaves are large, cut them in half.
How to root your cutting
Dip your cuttings into rooting hormone and place in a seed-starting flat full of sterile soil, or you can place your cutting directly into a sheltered spot in your garden. If you place your cuttings in the garden, make sure they have afternoon shade. Keep your cuttings watered. If they start to wilt create a mini-greenhouse by placing a cloche over them or tenting clear plastic over the cuttings. For softwood cuttings, you should have a fully rooted replica of the parent shrub in four to six weeks.