Stem cuttings

Stem cuttings involve removing part of a plant’s stem and growing it on to become a complete new plant.

Taking cuttings involves damaging the plant in some way (in this case by removing a piece of stem) so that the plant starts to repair itself. In this regenerative process cells within the plant become ‘meristematic‘, meaning that they start to divide to create more cells, which can mature to become any type of cell. In stem cuttings some of these new cells will mature to form the plant’s roots. In root cuttings, some will form a new stem and others new leaves. This process happens more or less easily depending on the types of plant. Ivies, for example, are pre-disposed to form new roots (this is how they cling to surfaces), whereas some tree stems will form hard calluses (like a scab) over a wound through which it can be difficult for new roots to grow. Hard calluses can also be caused by planting the cutting in growing media which is too aerated or where the pH is too high (alkaline). Hard calluses can be carefully scraped off the cutting to encourage rooting.

When taking cuttings of any kind there are some key things to remember:

  • Hygiene is very important. The cut you make instantly becomes an easy entry point for plant diseases, so you need to ensure that all cutting tools, your hands and even the working benches are suitably clean.
  • Ensure that all cutting instruments are as sharp as possible, so all cuts are clean.
  • All plants differ in terms of the type of cutting which works best, when to take the cutting, how to take the cutting, and the aftercare required. Make sure you check what your plant needs before taking your cutting.
  • Always select a healthy and true to type plant and stem to take the cuttings from.
  • Cuttings should be from a non flowering stem, so check for flowers or flower buds first. Easy to root plants can be exceptions to this rule (eg pelargoniums) although all flowers and flower buds must be removed prior to propagation. Heathers can be problematic, so select stems with the fewest flower buds on them and cut your propagation material from sections without flower buds.
  • You should aim to have as little time as possible between taking the cutting and planting it. All cuttings, except hardwood cuttings, are very prone to drying out and should be taken in the early morning so they are fully turgid (or water the parent plant well a few hours before taking the cutting), stored in a plastic bag (ideally a co-extruded bag which is black on the inside and white on the outside) and used as quickly as possible. If you can’t plant them the same day, then keep the sealed bag in the refrigerator until the next day.
  • If you are taking multiple cuttings try to ensure that they are all the same size, that way they will all be ready to pot up and plant on a the same time, making your life easier.
  • For stem cuttings, always make a slanted cut at the top of the cutting and a straight one at the bottom, so you remember which way up to plant it. With root cuttings the opposite is done (a straight one at the top and a slanted one at the bottom).
  • Softwood, greenwood and semi-ripe cuttings may benefit from having a fungicidal spray applied before they are planted, to reduce the risk of botrytis (grey mould).
  • Make sure you care for your cuttings after they’ve been taken. In warmer climates most cuttings can be planted outside in a sheltered, shady area. However, in cooler climates, protection may be required for the cutting and ‘bottom heat‘ of around 15-25°C  (bottom heat can be provided by a heating map, heated propagator, etc) with cooler air around the tops can encourage the plant to put its energy into rooting rather than top growth.
  • Ensure that all cutting material is clearly labelled so you know what it is and when you planted it.
  • Give the parent plant a bit of care and attention after taking the cutting, particularly if you have taken a lot of cuttings from one plant. Tidy up the top growth, remove any weeds and give the plant a good feeding, watering and mulching.

There are various types of stem cuttings, which are categorised according to the age of the material being used and by the type of stem section used:

By age of material used

By type of stem section used

By age of material being used

Softwood

These cuttings are usually taken from the first flush of growth on the plant in the spring. The cuttings tend to be slimmer and ‘floppy’ compared to semi-ripe cuttings. They are the easiest to root of stem cuttings, but are the most prone to drying out or fungal diseases (due to being easily bruised), so the survival rate can be low.

Ensure that the pots or trays to contain the cuttings are already prepared, to reduce the time between taking the cutting and planting it. Use cutting compost so that it is free draining (eg half peat/coir and half sand/fine bark or a third peat/coir, a third fine bark and a third perlite) and add an inorganic slow release fertiliser to the compost if you wish. Alternatively cuttings can be placed in rockwool or similar blocks. Ensure that the growing media is moist.

Each cutting should be 8-10cm in length for trees or shrubs and 8-13cm for herbaceous perennials, and can be dipped in hormone rooting compound before planting if it is difficult to root. The very soft tips of the stems should be removed as they are susceptible to rotting and scorch. Use a dibber to make a hole in the compost so that you don’t damage the cutting when inserting it, and firm the cutting in gently.

The planted cuttings should be placed away from direct sunlight, in humid conditions, such as a closed propagator, mist bench or plastic film tent, ideally with bottom heat of 18-24°C for tree cuttings, around 15ºC for shrubs and 18-21°C for herbaceous perennials. Keep the growing medium moist. Remove the cover for 10 minutes a couple of times a week to allow them access to fresh air. If you don’t have these facilities, then put the cuttings in a pot, cover it with a clear plastic bag, not touching the cutting (use an elastic band or string around the bag and pot to keep it in place) and place it on a shady windowsill indoors. The cuttings should be rooted within 10 weeks and should be potted on the following spring (or earlier if it is well established). For shrubs and herbaceous perennials the tips of each stem should be pinched back to a node to encourage bushier growth. Trees grown from softwood cuttings should be ready to plant out in 2-3 years.

If the base of your cutting rots, and you catch it early enough, you can cut off the base and, if the remaining cutting is long enough, re-plant it. Use fresh compost and spray with a copper based fungicide to reduce the risk of further rotting.

Greenwood

Slightly older than softwood, greenwood cuttings are taken from growth which is just starting to firm up. This makes them less ‘floppy’ than softwood cuttings. Because they are from sturdier growth they are less prone to drying out and fungal diseases. They should be managed in the same way as softwood cuttings.

Semi-ripe

Semi-ripe stems are still from this season’s growth, have buds developing and are quite firm compared to softwood cuttings (although the tip will still be fairly soft). The cuttings will vary in length depending on the plant; cuttings from trees and shrubs should be 10-15cm in length (or as short as 5cm from younger conifer growth), heathers around 5cm long and herbaceous perennials between 8 and 13cm. When taking cuttings from conifers you should bear in mind that evergreen conifers (except pines) have specialised buds which will be pre-determined to grow either as upward, leading shoots or lateral, sideshoots. So if you take a cutting from a sideshoot then you may not get upward growth to form the required shape. Cuttings from conifers should be from younger growth which does not have any fruits (ie cones) on it.

Once you have taken the cutting, remove any foliage from the lower part (except pine needles which can be retained) and dip it in a hormone rooting compound and, making a hole with a dibber, put it in a suitably sized tray or pot filled with cutting compost (eg half peat/coir and half sand/fine bark or a third peat/coir, a third fine bark and a third perlite). Alternatively cuttings can be placed in rockwool or similar blocks. Ensure that the growing media is moist. An inorganic slow release fertiliser can be added to the compost. Use the dibber to firm the soil around the base of the cutting.

For most plants, the cutting should be kept in a frost free place and in a propagation unit or under a plastic bag (ensure it doesn’t touch the cutting) to keep the atmosphere humid. Remove the cover for 10 minutes a couple of times a week to allow them access to fresh air. Bottom heat around 18-21ºC will help the cutting to root, particularly for tender plants (if you’re using bottom heat for conifers then this is best for late winter cuttings, autumn cuttings can be placed in a well lit cold frame). Ensure that the compost is kept moist and any dead leaves are removed to prevent rotting. Some cuttings can be planted outside in a nursery bed, but still covered to keep it humid and shade it from direct sunlight.

Generally the cuttings will root over the winter and be ready for potting on by the spring, although conifers are unlikely to be rooted until the summer. Keep an eye on the cuttings, remove any fallen leaves and ensure the compost doesn’t dry out. Remember to harden off cuttings grown under cover before moving them into less protected conditions.

Ripewood

This is wood which is fully ripe, or woody, and is an age of cutting generally used for conifers. Cuttings are dealt with in the same way as semi-ripe cuttings.

Hardwood

These are taken from woody perennials (either deciduous plants or evergreens with broad leaves) when they are dormant, which is generally between mid/late autumn and late winter. The best time to take them is just after the leaves have fallen (for deciduous plants) or just before the buds break in late winter. They are slower to root (because the stem is dormant) but much less likely to dry out and more likely to survive than softer cuttings.

The hardwood cutting should be taken from wood which is one year old or, if the plant is vigorous, then this year’s well-ripened growth. The length of the cutting can vary from plant to plant, but a general guide is that it should be at least pencil thick and around 20cm long (roughly the length of a pair of secateurs). The cutting should be taken flush to the main stem or just above a bud. When preparing the hardwood cutting, a slanted cut should be made at the top just above a bud and a straight cut at the bottom just below a bud. Make sure that the cutting is orientated the same way it was on the plant, ie so the slanted cut for the top of the cutting is at the top of the cutting, as it was on the plant.

If the plant is fast rooting the cutting can be planted outdoors in trenches made with a spade, about 10-15cm apart (or make holes with a large dibber if the soil is friable). The site should be free-draining, sheltered and weed free. You can pour a little sharp sand into the base of the trench to ensure good drainage. If you are planting more than one row then they should be 30-38cm apart. Where the plant is a multi-stemmed woody perennial or a fruit tree then the cutting should be planted so that it is two-thirds to three-quarters buried. If it is a single stemmed ornamental woody perennial then it should be planted so that only the top bud is visible above the soil surface. Make sure the cuttings remain well firmed in over the winter and that the soil isn’t lifted by frost.

Alternatively the cuttings can be planted in containers. Select pots which are tall enough to incorporate the cutting and root growth and put three to five cuttings around the edge of each pot. Keep the soil moist and put the pots in a sheltered location (eg a frost free greenhouse or sheltered cold frame). To save space, the cuttings can be kept tied in bundles in fine grit or in rolls. To create the rolls, cut a long sheet of black plastic, which is slightly wider than the height of the cuttings and cover with a layer of fine bark and peat/coir. Place the cuttings on top about 8cm apart, then carefully roll the sheet up, so the cuttings are held between the rolls. Tie it in place with a piece of string.

Where you are taking cuttings from a slow rooting plant or from an evergreen, it may require some extra help to root. In these cases, bundle the cuttings up into groups of 10 and tie them together. Dip the flat cut ends (ie the bottoms) in a hormone rooting compound and put them, half buried, into a box of moist sharp sand or sandy soil in a sheltered place (a cold frame is ideal) over winter. If you have facilities, you can give them bottom heat during this period, which will speed up rooting. By the spring you should see root growth and can plant them into trenches as described above for fast rooting cuttings.

Evergreen hardwood cuttings should be kept in more humid conditions (eg under a plastic film tent) to reduce the water lost through the leaves.

The following autumn (after leaf-fall for deciduous plants) the cutting should be ready to be lifted and planted in their final location or potted up (if they aren’t well developed grow them on in a nursery bed for another year).

By type of stem section used

All cuttings, except hardwood cuttings, should have at least one leaf left at the top of the cutting so that the plant can continue to photosythesise, so that it continues to produce energy for growth. Any leafy growth or snags should be cleanly removed from the lower portion of the cutting so it does not go into the soil and rot. If the leaves at the top of the cutting are numerous and/or large then some should be removed and the remaining one or two leaves can be cut in half; this reduces water loss through the leaves.

Nodal cutting

With nodal cuttings, the bottom cut is taken just below a node. A node is the part of the stem where new growth occurs; it is usually slightly swollen and may have a bud, leaf or stem growing from it. This is one of the sites where the meristematic cells which are responsible for regeneration congregate, so taking the cutting just below it guarantees that there are lots of cells ready to become new roots. Nodal cuttings are particularly useful for hard to root plants.

Internodal cutting

An internodal cutting takes the bottom cut between two nodes, so the roots have to grow out of ‘normal’ stem material. Internodal cuttings have the benefit that more cuttings can be taken from each piece of stem, however they are harder to root than nodal cuttings so aren’t appropriate for all plants.

Stem-tip cutting

These are cuttings where the softest growth at the tip of the stem is retained. They are usually taken in mid summer when the plant has ripened past the softwood/greenwood stage, to reduce the risk of the tip rotting. The cuttings are usually nodal, to encourage rooting, and around 10cm in length (4-5cm for rose softwood stem-tip cuttings taken in spring). Due to the softness of the tip growth they are generally treated as softwood cuttings.

To save space, stem tip cuttings can be rooted on lengths of black plastic covered with sphagnum moss or a peat/coir and fine bark combination. Place the cuttings about 8cm apart onto of the growing medium so that the tips are sticking out over the edge of the plastic. Then roll the black plastic up so that the cuttings are held between the layers and tie in place. Tease the cuttings out of the growing medium and pot on once they are rooted.

Leaf-bud cutting

Leaf-bud cuttings involve taking a short piece of semi-ripe stem and one leaf; meaning that quite a few cuttings can be taken from one piece of stem. They can be nodal or internodal and, if the stem is thick enough, can be split (see ’splitting’ below). This economical way of taking stem cuttings is often used for shrubs and climbers.

When taking a leaf-bud cutting, ensure that the nodal area at the top (ie the area where the leaf joins the stem) isn’t damaged by cutting into it. Leaf-bud cuttings shouldn’t need to be wounded, but this might help rooting where the stem is very woody.

Heel cutting

Instead of cutting a piece of stem away, heel cuttings involve gently pulling a sideshoot (which is around 10cm long) off the stem so that it keeps a small sliver or ‘heel’ of the bark from the main shoot. The heel should be trimmed slightly to remove any soft, bark material. Heel cuttings are generally used for semi-ripe cuttings, but can be used for hardwood, greenwood or softwood. They are useful when there isn’t enough long material to do normal semi-ripe cuttings.

Mallet cutting

Mallet cuttings involve taking a section of last year’s growth (the ‘mallet’) which has a sideshoot of the current season’s semi-ripe growth coming out of it. A section about 1cm in length is cut from last year’s growth with the cuts just above and just below the side shoot. The lower leaves and soft tip of the sideshoot are removed and the cutting then treated as normal semi-ripe cuttings. If the mallet is more than 5mm in width then it can be split (see ’splitting’ below). This is a useful method for cuttings where the current season’s growth is thin and insubstantial.

Basal cutting

These cuttings are entire new shoots (which are 5-10cm long) taken very early in the growing season from herbaceous perennials (or in late winter from plants forced into new growth). They are severed from the crown of the plant so that each cutting has a piece of the parent plant still attached at the base of the cutting. Clear soil away from the crown of the plant to reveal the whitened, basal stem and cut the section as far down as you can. Any soft material should be removed from the bottom third of the cutting to reduce the risk of rotting. The cuttings should be planted in cutting compost so they are half buried. As these are taken very early in the season they can form good sized flowering plants that season. This can be particularly useful for hollow stemmed plants such as delphiniums and lupins where normal softwood cuttings rot easily; the addition of the section of basal plate with the cutting effectively ’seals’ the hollow stem to protect it.

Splitting

Splitting cuttings can result in more plants from a single cutting and therefore is very economical. A relatively thick stem cutting should be taken, which has one or two nodes (growth points where buds form) on it, and cut in half lengthways. Each half can then be laid, cut side down, on appropriate growing media. Splitting can be done with cuttings from plants such as Dracaena species.

Wounding

Wounding a cutting involves cutting a slither of bark away from the bottom of the cutting to expose more of the meristematic (growth) cells and therefore encouraging the production of root cells. It can also increase the uptake of water. The cut should be about 2.5cm in length.