How-To: Propagate Plants Using Soft-Tip Cuttings
There is a profound joy in propagating plants. Advocates of maximalist planting, like me, get very excited about propagation because, well, the more plants to tend and share, the better. The propagation of beauty need not stop and start with germinating seeds. Vegetative propagation is a brilliant technique to grow a huge number of plants on the cheap. Put simply, a section of the stem is cut off and used to propagate a new plant.
Stem cuttings are often called ‘soft-tip cuttings’ or softwood cuttings, because the softest green tip of a plant, rather woody or woodier sections, is used. Soft-tip cuttings have the highest potential to form a root system than woodier parts of a plant.
Cuttings are ‘clones’ of the parent plant, and in most cases will have identical characteristics. Sometimes there can be a bit of variation in the form of the new plant if you take the cutting from the top vertical tips compared to the lower horizontal branches, but don’t get too caught up in the exceptions when you’re starting out.
The stem section that you use as your cutting needs to contain the tip of the stem and nodes or lateral buds, the ‘leaf joint’. Nodes are wondrous things. The wounding of plant tissue below a node or will create a response in the plant to heal the wound (the location of a cut or prune) and initiate the formation of adventitious roots. Amazing!
Plants can naturally form adventitious roots without a gardener’s helping hands, but you can gently push things along.
Get started on soft-tip cuttings with hardy and tender perennials like sedum, pelargonium and salvia, or with shrubs like buddleia and hydrangea. Once you have the knack for snipping, it is pure joy to experiment with what is at hand in your garden, or in fact, your neighbourhood, to create your very own plant army.
A step-by-step guide to soft-tip cuttings
- Prepare a free draining cutting mix to grow the cuttings in and allow the roots to form. Either purchase or make your cutting mix with 50% of seed raising mix or fine sieved potting mix and 50% of rough, clean sand or perlite. There are plenty of recipes to find and try.
- Choose stems that look healthy and free of disease and pests. Avoid flowering shoots – shoots without flowers form roots more easily. Take your cuttings in the morning, while the plants are full of water. Place them in a plastic bag while you collect more to keep them fresh (even with a bit of water for humidity). A clean recycled plastic bag is fine if you have one at hand.
- Once you have the cutting material, it’s best to not dilly-dally. Start making cuttings as soon as you can. If you get delayed, you can store the bag in the fridge with a label for a short time, so the stem does not wilt.
- Fill clean pots or containers with the cutting mix. Water the pot well so there is moisture to the bottom of the pot.
- Create a cutting by cutting the stem below the node. Remove the set of leaves and trim the foliage down to about a 3rd. Trimming excess foliage from the cutting reduces pressure on the plant to support the transpiration of the leaves without a root system.
- Dip the node into a rooting hormone powder or gel (not essential). Hormone poweder is like a kickstarter – increasing the chances or speed of the cutting forming a root system. Honey can be used to sterilise the wound, but the science is uncertain on the benefit of honey encouraging roots to develop. Many plants will still grow a root system without using a hormone, but it will speed the process up.
- Take the cutting, use a stick or a dibbler to make a hole in the potted cutting mix and gently place the cutting in, nudging the mix around it. Repeat the process until your pot is full of cuttings. This is often referred to as a ‘community pot’ with multiple cuttings in the same pot. The numerous cuttings assist in holding the humidity and creating a little microcosm for the cuttings to thrive in. Greatness is in numbers, as they say.
- Do not water afterwards, as it will wash off the hormone if you have used it. Use a spray bottle or mister to ‘water’ the foliage. Place in a warm location either in a greenhouse – big or small – or create your own by placing half a clear plastic bottle over the cuttings or using a clear plastic bag to make a little DIY greenhouse.
Caring for your Soft Tip Cuttings
Cuttings need optimal conditions with warmth and moisture to produce roots. As the new cutting is without a root system, it needs to absorb moisture from its remaining foliage. Spray the leaves and stems with a mister or spray bottle two to three times each day, and water every couple of days. The cutting mix should be damp but not overly saturated, to keep the cutting from rotting.
If any cuttings look sick, remove them and any fallen leaves from the ‘community pot.’
The appearance of visible roots from a cutting varies. It can typically take between 10 days to 3 weeks, and then a further 3-4 weeks for the root system to be significant enough to pot the individual plant up.
Roots poking out the drainage hole of a pot or container are a sign that it is time to pot the cuttings up in individual pots. Such wonderous excitement when you see those new roots poking through! A butter knife or stick is a handy tool to gently press into the pot and lever the new plant up while gently holding on to its leaves. Allow the plants to grow in their pots outside and harden up before planting them or sharing them with plant people.
Cutting season: Early Spring to early Summer
If you live in cooler climates, the ideal time to take soft tip cuttings is from early spring through to early summer. This is when most plants are naturally going through a growth spurt. Also, there is enough time for the new plants to form a sizeable root system and be potted and transplanted before the cooler months. You can succeed if you create warmer conditions, i.e., in a greenhouse, but as with all kinds of gardening techniques, it is easier when we work within the natural rhythms of nature.
Go forth and propagate!