Grow more plants from the ones you have already in your garden! It’s easy to do and is a great way to increase your plants, especially those that are rare, heritage or expensive.
Using sharp garden secateurs (pruners), snip off shoots from the plant. Choose reasonably new but mature growth from the parent plant. Choose a length for the cutting. Generally, cut about 8 to 10cm/3 to 5 inches for perennial and 15cm-30cm/6 to 12 inches for shrubs. Since the size varies according to the plant, you might need to practice some trial and error again. When cutting, unless advised otherwise by advice on the particular plant, cut at a 30 degree angle, leaving the cutting with a point. Small cuttings are best for smaller plants and shrubs, while larger cuttings (called "truncheons") up to a metre or two long and 5-10cm/2 to 4 inches thick can work best for larger plants such as poplars and mulberries. If in doubt, make the cuttings about 10-20cm/4 to 8 inches long.
Strip a half to two thirds of leaves from the lower part of the cutting. Be sure to remove the bottom two leaves and pinch off the top pair of leaves too. Remove flower buds because they will suck the nutrition out that the plant needs during the time it is growing new roots. It is best to cut the plant about 1/2cm-1cm/1/4 inch to 1/2 inch below a knot (a knot has two small branches or two leaves) because roots tend to grow around and underneath a knot.
Treat the cutting. Treating the cutting gives it a better chance at taking root because it has nutrients to encourage it. Place the cuttings in a weak mixture of water and a seaweed-based liquid fertilizer for a period of 3-4 hours. If possible, put the cuttings under a single fluorescent light. After this, dip the cut end of the cutting in rooting hormone just before planting it.
Create the rooting medium. Start the cutting in sand, soil, or even just water. Some cuttings actually produce roots better in water than in soil––again, you'll need to either experiment or read up on the specific plant's preferences. Sand is a sort of compromise, but should be treated like water when it comes to adding fertilizer. Use a pencil or a chopstick to create the hole for the cutting to slip into. The cut end should be inserted to a depth of around 2.5-5cm/1-2 inches, although this is dependent on the length of the cutting. Keep the cuttings out of direct sun. When using water as the planting medium, make it a very dilute fertilizer mixture. Also make certain the plant does not get direct sunlight, as the intense UV rays are hard on the roots. Aside from how well it works, another reason to use water is that you can see what's happening. This is not only fun (and great to involve the kids in), but also allows you to know when the plant is ready, without having to worry about guessing whether roots have developed. Once roots finally start, the rate of their visible growth can be astonishing, noticeably changing even hour to hour. If using garden soil, plant cuttings in a moist well prepared garden bed rich in organic material, with a pH around 5.5 - 6.0 (or you can place them in pots with good potting mix). Space the cuttings so they are about as far apart from each other as the cuttings are long. If using softwood cuttings, take the cutting and stick into moist soil straight in the garden. Simply water them and in a year or two, they'll be growing along with the best of the garden.
Water well when first planted. Then, keep the cutting moist, but not over watered (try a mister). Success rates can be anything between zero (some plants cannot be rooted from cuttings at all) and 90 percent. Try not to get discouraged if it doesn't take; equally, don't be surprised by initial wilting in the first few days––that's normal. Covering the cuttings with a plastic bag loosely (to allow for continued airflow) can help trap adequate moisture. Trees are the hardest to grow from cuttings, while cactus and succulents are the easiest. Plants with water retaining leaves like lavender and geraniums work almost 100 percent of the time.
Transplant the cuttings to their final growing spot once you're certain they have taken root. With large 'truncheons' of willow, poplar or mulberry, trim a point on the bottom end, and ram the cutting into the ground for three quarters of its length, so that just a small part sticks above ground. This action is best done right where you want the tree to grow; no further action is necessary apart from keeping weeds and plant-eating animals (rabbits, deer, kangaroos, etc.) away. To test for roots, give the cutting a very gentle tug. If you feel resistance, it means that the roots have begun to form and are growing. Don't be rough with this action or you could destroy the cutting.