Plant propagation methods

It’s fun, economical and deeply satisfying to grow a garden from cuttings, divisions or seed. Here, we take you through the basics…

Buying plants can be a costly business, especially when the addiction sets in! But creating a garden filled with beautiful plants needn’t break the bank. Armed with some basic propagation skills and a bunch of easy-to-reproduce plants from the nursery (and whatever you can beg, borrow or steal from friends!), you can quickly start or fill out a garden for little cost. It’s the perfect solution if you’re renting or just don’t want to pour a lot of cash into the garden. What’s more, growing a garden from divisions, cuttings and seeds is not just economical, it’s fun. And the level of gardening satisfaction grows exponentially when you know you’ve done it all yourself! Here are the different plant propagation methods:

Divisions

Division is literally about taking one plant and pulling it apart to make two (or more). It’s probably the easiest way to make new plants, and the effects are almost instant. You can propagate a number of plants this way, including bulbs, ornamental grasses and many flowering perennials.

BULBOUS PLANTS
Bulbs, corms and rhizomes multiply over time, creating bigger clumps that can be easily split. For the ones that die down (for example, daffodils), it’s best to dig them up during their dormant period. Use a shovel or fork, working from the outside edge of the clump. Don’t start too close to the clump or you’ll risk slicing through the bulbs.

Once they’re out, shake off the excess soil and divide them into individual or small groups of bulbs. Most true bulbs and corms, including tulip, freesia and gladiolus, will separate easily with your hands. Rhizomes and tubers, such as dahlia and canna lily, need to be cut apart. With all types of bulbs, discard any that are soft or damaged. Replant small clumps at the same soil depth and water in.

Evergreen bulbs, such as agapanthus and clivia, can be divided anytime, except when the plant is just about to flower. Dig up the clump and tease apart the bulbs. In some cases, you may need to cut through a congested clump with a serrated knife to create divisions. Trim back some of the old roots, leaving a bit on each bulb. Remove some outer foliage to reduce transpiration while the divisions recover and generate new roots. Replant bulbs quickly into the new locations, and water in with seaweed solution to stimulate root growth.

HERBACEOUS PERENNIALS
These are plants that produce fresh growth each year from their base while the old growth dies off. Many are classic cottage garden plants – think penstemon or wind anemone. In winter, simply cut the old growth off down to the ground and dig up the plant. Shake off the loose soil and use secateurs or a sharp knife to divide the base into small sections to replant. Water in with seaweed solution, keep moist, and fresh growth will appear in spring.

CLUMPING GRASSES
These are similar to herbaceous perennials, as many have a winter dormancy followed by a spurt of fresh growth in spring. Mid to late winter is the best time to dig them up, then cut back their grassy tops, leaving 5–10cm at the base. Use a knife or sharp shovel to cut through the clump to create smaller divisions for planting. Other plants that have strappy leaves but are not true grasses, such as mondo grass and dianella, can be lifted and divided at any time of the year. However, spring and autumn are the least stressful times for the plants. There’s no need to cut back the foliage, but ensure that each new piece has a decent amount of root mass. Replant and water well.

Cuttings

Taking cuttings can seem daunting, but it’s easy once you understand the basics. There are three main types of cuttings: softwood, semi-ripe and hardwood.

For all cutting types, only select stems that are fresh, undamaged and free from any pests or diseases. Use sharp, clean secateurs to cut each section and remove the lower leaves (if present). Keep only one or two sets of leaves at the very top. With deciduous cuttings, keep track of the top and bottom of the stem so you don’t plant it upside down. Before planting, dip the base of the cuttings into rooting hormone powder or gel (readily available at garden centres) or raw honey to improve root formation. And make sure you plant into a propagation mix that is light and airy, but also holds moisture.

Cuttings usually fail because they dry out before roots develop. To avoid this, water your potted cuttings, then cover with a clear plastic bag, which forms a mini greenhouse.

Place in a bright spot out of direct sunlight until new growth appears, which indicates roots have formed. While softwood cuttings will develop in just a few weeks, hardwood cuttings can take several months.

SEMI-RIPE CUTTINGS
These cuttings are taken from young growth that is about six months old and has started to harden, but not yet become old and woody. They should be 10–15cm long, and taken in summer and autumn. If they have a very soft growing tip, you should pinch this out.

SOFTWOOD CUTTINGS
These tip cuttings, which are generally 5–10cm long, are taken from new growth that is green and supple. They are most commonly taken in spring or whenever a plant is producing new growth.

HARDWOOD CUTTINGS
These types of cuttings utilise mature stems that are firm and woody. They can be taken from evergreen plants from late summer to early winter. For deciduous plants, take cuttings from late autumn to winter, when the plants are dormant. Cuttings should be 15–20cm long and at least 1cm in diameter. Read more in our article, Take hardwood cuttings.

Seeds

Many plants are super easy to raise from seed. A packet of seed only costs a few dollars and comes complete with sowing instructions. Alternatively, you can collect dried seed heads of flowering annuals from friends’ gardens, and scatter them at your place. Here are some reliable germinators, many of which will self-seed year after year: