Feature

Propagating 101

G Magazine

With a little time and patience, you can fill your garden with your favourite plants, without breaking the bank. Here’s how to propagate plants from your own garden… or someone else’s.

How to propogate

A step by step guide to propogating.

Growing from seed

Try to catch the seed at its perfect ripeness.

Taking cuttings

Using a sharp pair of secateurs, take cuttings 10–15cm long.

Grafting

Grafting involves attaching a cutting of a plant favoured for its fruit or flower onto a preferred rootstock.

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Few things are more fun for garden lovers than wandering around a well-stocked nursery admiring the massed displays of plants. You can choose plants for their colour, shape or scent, find the perfect plant for borders, screens, birds or the vegie patch, and select varieties that thrive in sun, shady spots or indoors.

But if you find something you like that you’ve also spotted in your neighbour’s garden, why not resist the urge to buy and instead offer to swap seeds or cuttings. You will have new plants up and growing in no time.

Propagating is a cost-effective way of filling your garden, and growing seeds and cuttings from your neighbourhood means you’re getting varieties that have already proved suitable for the local climate and soil. It can also lead to some wonderful gardening friendships. Autumn and winter are great seasons to experiment with propagating, but spring and summer can still be good, plus propagated plants make especially good, thoughtful Christmas gifts - so here are a few pointers to get you started.

GROWING FROM SEED

Collecting seed from a favourite vegetable or flower usually results in the same variety, but beware: not all plants grow true to type. This might not matter for annuals, but you could wait years for apple trees to fruit, only to find the apples taste horrid, so they are often best grafted instead.

Step one:
Collecting seed
It may take some trial and error to catch seed at its perfect level of ripeness. One way is to tie a paper bag around the ripening seed head to catch ripe seed as it drops… or explodes, as some pea plants do!
Some plants hide their seeds in hard pods or inside fruit, and these must be extracted and dried. Tomato and pumpkin seeds grow better out of slightly rotten fruit, so they benefit from a day or two of getting mouldy in a cup of water before being cleaned and dried. Harder native plant seeds, such as acacia, banksia and hakea, need heat or smoke treatment to germinate. Jars are good for storing dried seed, but remember to label them.

Step two:
Planting
To germinate, seeds need to be in contact with warm, moist soil. If you are impatient to get growing in garden beds, start with larger seeds such as peas and beans. For more delicate seeds and more consistent results, grow seedlings first in a container where you can control pests, moisture and temperature, then transplant the seedlings into the ground. Use seed-raising mix, which is weed-free, sterile and fine enough for small roots to navigate. This also retains moisture and provides good drainage. You can also make your own seedling mix from three parts compost and/or worm castings, one part clean sand, and one part cocopeat (coconut husk fibre).
As a general rule, plant seeds as deep as their own size, so just lightly cover small seeds and plant bigger seeds deeper. Any shallow, flat container with drainage holes will do. Try reusing tomato or strawberry punnets, or use egg trays, which can be planted directly into the ground later. Cardboard milk cartons are good for trees.
Keep the soil warm and moist, but not wet. Avoid full sun.

Step three:
Maintenance
Thin-out thickly growing seedlings by removing the smallest ones. If you don’t do this, the whole crop may succumb to mould and be lost. When seedlings are big enough, transplant to a compost-rich garden bed or pot. Protect from slugs and snails.

HINT:
Label all seeds & cuttings so you don’t forget what you’re growing.

Some easy seeds to try:
Radish, broad beans, love-in-a-mist (Nigella damascena), alyssum, salvia, peas, calendula, stock, tomato, zucchini, cosmos, nasturtium, sunflower, rocket, lettuce.

TAKING CUTTINGS

Some plants grow better from new growth, while others do best from hard wood; if in doubt, try some of both. Succulents will grow from a single leaf. The easiest cuttings sprout roots in a vase of water or seaweed solution, and simply need potting up.

If you can’t plant a cutting immediately, wrap it in damp paper or place in a moistened zip-lock bag and store in the fridge. For centuries, explorers kept cuttings of exotic plants in sawdust for the journey home, and the cuttings often survived months at sea.

Here are some simple steps for taking cuttings:
Step one:
Using a sharp pair of secateurs, take cuttings 10–15cm long. Trim the bottom at an angle, just below a leaf node (the swollen part of the stem where leaves emerge from) if possible. Trim any leaves from the bottom of the cutting and remove flowers, fruit or buds, as these divert energy needed for root growing. If the plant has large leaves, cut these in half. The leaves are the plant’s main source of energy, through photosynthesis, so they help the cutting to grow.

Step two:
Some gardeners find it helps to stand the cuttings in a weak mix of seaweed solution for a few hours before planting up. Others also scrape a layer of bark off the bottom centimetre of woody cuttings to create a bigger scar, as this is the part that produces roots.
Hormone solution, powder or gel can speed up root production too, but shake any excess off the cutting.

Step three:
Fill a pot with seed-raising mix. Use a pencil to make a small hole in the mix then insert the cutting and press the mix around it. Cuttings grow best in warm, humid conditions so it’s best to fill the pot with a number of cuttings as they create their own microclimate.

Step four:
Water your cuttings with a fine spray. Cover with a plastic bag, held away from the cuttings by a wire frame and tied around the base with an elastic band, or use a clear plastic drink bottle with the base removed.

Step five:
Commercial growers propagate cuttings on a heat mat, but a polystyrene box or a warm, protected place in semi-shade, such as on top of a water heater, will do. You could also place a plastic cover over the plant (though not touching, such as a plastic cup) to create a mini greenhouse, particularly if you live in a colder area.

Step six
Remove any cuttings that blacken or show mould. After 6–8 weeks, gently ease out a cutting to check for roots. When ready, pot up individually.

HINT:
Transplant young plants in the morning and water with a weak solution of seaweed conditioner to reduce shock.

HINT:
When using hormone gel or powder, use a small amount in a separate container and throw away leftovers; dipping cuttings into the main pot risks contaminating the lot.

Some easy plants to try:
Chrysanthemum, tamarillo, dahlia, murraya, grevillea, fuchsia, African violet, geranium, gardenia, correa, grapevines, mint, basil, succulents, wisteria, honeysuckle, Virginia creeper.

GRAFTING

Grafting involves attaching a cutting (scion) of a plant favoured for its fruit or flower onto a preferred rootstock. You can graft a second or third fruiting variety to an existing tree, choose a rootstock that keeps your tree small, or attach a stunning desert flower to roots that tolerate higher rainfall.
The aim is to join the cambium layers of bark. This can be done in many ways, but the simplest is a cleft graft, which works especially well when adding a new variety to a fruit tree. For fruit trees, grafting is best done in mid-to-late winter, when plants are dormant.

You will need a sharp, disinfected penknife or grafting tool, some grafting tape or wax, a small, disinfected nail or other wedge, and rootstock that is compatible with your chosen scion (closely related species are usually a safe bet). As an alternative to tape or wax, try petroleum jelly to keep the graft watertight, and some electrical or plumber’s tape to hold the pieces in place.

Step one:
Remove the limb or sapling trunk with a flat, clean cut.

Step two:
Make a vertical cleft through the centre of the cut stem, down about 2–3 times the width of the stem. Hold the cleft open with the nail or wedge.

Step three:
Cut the bottom of the scion wood to a thin wedge.

Step four:
Gently insert the scion into the rootstock, making sure to line up the layers of bark. If the scion wood is much thinner, you can insert two pieces, one on each side of the cleft.

Step five:
Starting just below the cleft, firmly wrap the graft in tape, or cover with wax, to keep it clean and moist. As soon as new growth appears on the scion –about 6–8 weeks – remove the tape or wax.

HINT:
Make your own mini-greenhouse for seeds, seedlings or cuttings using a polystyrene box with a glass or perspex lid.

HINT:
When wrapping a graft with tape, keep it firm but not tight – the sap must still be able to flow.

Some easy plants to try:
Apple, peach, plum, citrus, roses, camellia, hibiscus, macadamia, grevillea, hakea, native mint bushes (Prostanthera spp.).