The art of propagating your plants

A friend has threatened to visit my garden to take some cuttings, so I thought I’d look up some real advice. I have had limited success with cuttings, having a ‘cut off, plonk it in, and see if it grows’ attitude, and generally have been successful.

Several ways to propagate
Propagating largely depends on the type of plant you are trying to propagate. The main methods of propagation are cuttings, simple layering, division, budding and grafting, and of course, seeds.

Cuttings can be taken from nearly every plant, though the exact method will differ from species to species. Some plants are most successfully grown from leaf cuttings and woody plants - such as shrubs and some perennials - root best when treated with a rooting hormone and placed into a potting soil mix. Many soft-stemmed plants can produce roots in just a pot of water, and taking cuttings can give you full-grown plants in half the time it takes waiting for seeds to grow. Cacti are easy too, some grow babies that are very easy to separate from the parent plant or are jointed - like the Christmas and Easter succulents - which can be carefully twisted off.

When taking a cutting, choose a strong side shoot with no flowers and cut a piece between 5-10cm long, cutting just below a leaf joint. Remove all leaves from the lower half of the cutting and pinch out the growing tip.

Simple Layering simply means bending a low branch or shoot down to soil level, wounding the shoot, and then covering this portion with soil to encourage it to root. Honeysuckle and clematis can successfully be propagated in this way, and I have seen it done with oleander. Air Layering is more complicated, where root growth is enhanced from a branch of a plant, and once rooted they should be planted in soil.

Division of plants is easy – it usually involves the entire plant being separated into smaller, whole pieces that contain all vegetative parts (leaves, stems, roots, etc.), and creates a genetic clone of the parent plant. You might need to dig up the plant if it is in your garden or remove it from the pot if that’s where it lives. Lay it down, and with your fingers just split the root ball into separate parts – how many parts depends on the size of the root ball. Larger, denser root balls might require slicing into sections with a spade or a knife.

Budding is a little trickier, and most budding is done just before or during the growing season. However, some species may be budded during the winter while they are dormant. It involves inserting a single bud from a desirable plant into an opening in the bark of a compatible rootstock to create an advantageous variety (cultivar) and rootstock combination and is often used for fruit trees and on a large number of ornamental plants.

Lastly, seeds. Sowing seeds isn’t always a viable option, as some plants produce non-viable seeds or might be very difficult to germinate. But if you have the time, tomatoes are good grown from seed if you have a favourite in your salad, and packets of seeds for most things are readily available. You could just throw them down and hope for the best, but sowing in sterile topsoil will ensure your soil is clean and not overly alkaline or acidic, which could unwittingly harm your seeds.

Rooting hormone

Plants naturally produce a hormone called auxin that helps roots grow, but garden centres sell synthetic forms, usually a dry powder, and might be worth the small investment because it increases your cuttings' success. It's often sold in different concentrations, so using the correct concentration recommended for your type of cutting is important.

Tools

A clean, sharp knife, scissors or pruning shears would be useful, and disinfecting is recommended. Should cuttings be kept in the dark? No, the opposite, they need good light for faster root emergence. If the light is too low during propagation, leaves will be unable to get enough light for photosynthesis and rooting can be delayed.

---