How to propagate from cuttings

How to Propagate from Cuttings

In this lesson, I'm going to show you the different stages of propagation from cuttings. The plants I will be propagating are all tender plants, which means that they can't tolerate frost.

The plants I will be propagating are:

Pelargonium 'Tomentosum'

This is a great plant for shade pots as, unusually for a pelargonium, it can tolerate high levels of shade. In the autumn, when the nights get too cold for it to survive outside, I bring it indoors and keep it as a houseplant. It also has a beautiful peppermint scent.

Pelargonium 'Pink Aurora'

This pelargonium is a sun worshipper with bright pink trumpet flowers. It comes into flower very early and will add a splash of colour to your garden once the tulips have gone over in the middle of May.

This period between the middle of May and the middle of July is what I call the 'colour gap'. This is the time after the tulips and many other bulbs have finished flowering, but before the dahlias and the whopper pots have started to bloom. This pelargonium is a great example of a flower that can be grown to bridge the gap and provide some much-needed colour.

Salvia 'Nachtvlinder'

This salvia has a velvet purple flower but is also a tender plant, so it will need to come indoors during the autumn and winter, before going outside again in May.

Propagating Pelargoniums

Propagation of these tender perennials can be done in March/April or August/September.

A lot of these pelargoniums come from South Africa, so it's worth bearing in mind that spring in this part of the world takes place in August/September. It's possible to take cuttings at both times because of this, as the pelargonium cuttings will grow roots just as quickly in their 'genetic spring' as they will in the UK spring.

Rooting Cuttings

When you are ready to propagate from a cutting, you should always look for a non-flowering side shoot. This is because any stem with a flower bud on is already programmed to flower and so won't root as readily as a non-flowering stem.

1. You want to cut your stem immediately below a leaf or set of leaves with a clean and sharp pair of secateurs. As you can see on my cutting, there is already an axillary bud forming here, which indicates there will be a high level of the growth hormone that will encourage the plant to root in this area.

1. Remove any leaves that will be below the compost level as otherwise they will rot and may damage the success of your cutting.

1. Remove the growth tip of your plant. While this may seem counterintuitive, it will redistribute the growth hormone of your plant and will mean that the cutting will put energy into producing roots rather than producing new leaf and flower growth.

1. If your cutting has a large leaf, then cut it in half. While this might seem like an odd step, doing so will reduce the amount of water that your plant has to send to the leaf, which will mean it has more energy to put into root formation.

1. Fill a black or terracotta pot with compost. These pots will conduct heat better than others if they are placed on a horticultural electric blanket.

1. Place your cuttings around the edge of the pot, not in the middle. By doing this, when your cutting puts out its first root, it will hit the edge of the pot, break off and then produce lots of lateral roots, which will result in a quicker rooting process. You can put multiple cuttings in one pot, as long as they are around the edge.

1. Put your cuttings in a place with good air circulation and basal heat and they should root within four to six weeks.

Salvia 'Nachtvlinder'

These salvias were grown from cuttings last August, so they are now ready to pot on again before they go out into the garden in May.

If you see roots coming out of the bottom of your pot, don't worry. It is better to just pull the pot off and then tease out the roots if they are starting to become pot-bound. If you leave the roots without teasing them out, they will continue to grow in this fashion.

Put your plant into a bigger pot with fresh compost and remember to transfer your plant label too.

This salvia will eventually be part of a pollinator pot.

Pollinator Pot Recipe

• Salvia 'Nachtvlinder'
• Salvia 'Cera Potosi'
• Salvia 'Jezebel'

Salvias are early flowerers too, and can be in flower by the middle of May, helping to fill the colour gap along with the pelargoniums. They will then continue flowering until the middle of November.

Why Pot on the Rooted Cutting?

At this time of year, plants are going into a massive growth period so it's important to give them room to grow.

By giving them more space it means that when they eventually go outside they will be bigger plants, with stronger roots and so will flower faster than if they had been kept in smaller pots.

Protecting a Tender Perennial by Not Cutting It Back

Tender perennials come from warm climates, such as Africa and South America. This means that they generally have a much longer flowering and growing season, often flowering for five months, but they won't survive in cold weather.

On the other hand, hardy herbaceous perennials like peonies will only flower for three or four weeks but will survive outside in cold weather.

This long flowering season means that tender perennials are particularly useful for pots, as long as you remember to bring them in when the cold weather hits.

If you are growing pelargoniums and salvias in the ground, then it is possible to make them more hardy, simply by leaving them in situ in the autumn and leaving the frostbitten foliage on top. This can then be cleared away once you know no more hard frosts are due.

However, sadly this is not possible in pots as the frost is coming at the plants from all angles which makes them much more vulnerable.