One of the easiest propagation techniques is propagating using hardwood cuttings. Since these cuttings don’t have leaves, there isn’t the initial requirement to provide a high humidity environment to stop the cuttings drying out before they root.
Softwood vs. Hardwood Cuttings
At this point you may be wondering what the difference is between taking hardwood and softwood cuttings.
- Softwood cuttings are taken during the growing season, where the plants have leaves, so an important consideration is to maintain the humidity levels until roots begin to form to prevent the cuttings drying out.
- Hardwood cuttings are taken in winter, during dormancy, when all leaves have fallen.
I’ve discussed the basic theory of how plants can be propagated from cuttings in the article “How to Propagate Plants from Softwood Cuttings“, so I’ll go straight into practical instructions here.
How to Propagate Plants from Dormant Hardwood Cuttings
Hardwood cuttings are even simpler to prepare than softwood (herbaceous) cuttings, as we use cuttings from dormant deciduous trees and woody plants.
This technique is very useful for propagating fruit trees such as figs, pomegranates, mulberries and quince. Some plums can grow well from hardwood cuttings too, while others don’t do so well, it depends on the variety.
This technique is also used for propagating vines such as grapes and kiwi fruit, and the currant family – blackcurrants, redcurrants, golden currants and gooseberries.
The procedure for propagating hardwood cuttings is as follows:
Step 1 – Select Suitable Cuttings
Hardwood cuttings are taken from deciduous trees and plants (ones that lose their leaves in winter) when they are dormant, i.e. when they have no leaves. The best time for taking hardwood cuttings is from early autumn after the leaves drop to late winter.
Take cuttings that are close to pencil-thickness from current season’s (year old) growth, it will be mature and woody, not soft and green. Cut off any unripened green growth at the tips. To increase the chances of rooting cuttings:
- Try to take cuttings where the current season’s wood (1 year old wood) joins the two-year-old wood. The base of the stem at this junction has the greatest potential for root development, as it contains a large number of dormant buds that supply hormones required for developing roots.
- Take cuttings at leaf fall and just before the buds break and flowers begin to emerge.
Step 2 – Trim Cuttings to Size
Hardwood cuttings are cut much longer than herbaceous cuttings because they take more time to develop roots and therefore need to use the reserves of food stored in the cutting to keep them alive through winter. A longer cutting stores more food in it.
- Make a horizontal cut 6mm (1/4”) below the lowest bud at the base.
- Find a bud approximately 15-20cm (6-10”) away from the base to make the tip cut.
- Near this tip bud, make a sloping cut away from a bud, 6mm (1/4”) above the bud, so rain runs away from the bud to prevent it rotting.
Step 3 – Wounding the Cuttings
Species that are difficult to root should be ‘wounded‘ as this helps encourage rooting and may also help to remove a physical barrier of plant tissue which may get in the way of roots forming in some cases. This involves making an additional light cut on either side of the cut stem at the base to expose more of the cambium.
The cambium is the light green layer visible under bark when it’s scraped away, before reaching the wood underneath. It’s a single layer of meristem tissue that divides to produce new plant cells, including roots.
The bark or outer layer can be scraped off using a knife of the sharp edge of scissors or secateurs to expose the cambium underneath.
Step 4 – Dip Base of Cutting into Rooting Hormone (optional)
Treating cuttings with rooting hormone can increase the chances of stimulating root growth. This is more critical in plants that are more difficult to root. To do this, simply dip the base into the rooting hormone, that’s all!
Rooting hormone products can come in the form of liquids, gels or powders. If using root hormone powder and be sure to tap the cuttings to shake off excess powder.
It’s possible to make your own natural rooting hormone, see article – How to Make Home Made Plant Rooting Hormone – Willow Water.
Willow water is mild form of root stimulating hormone which contains IBA that can be made quickly and easily from willow tree twigs.
Step 5 – Insert Cutting into Propagating Medium or Ground
The cuttings can either be inserted into the ground in a ‘slit trench’, or into a garden pot of propagating medium or potting mix.
Since the cuttings can still lose moisture and dry out, even without leaves, we try to place as much of the cutting below the surface of the soil, while allowing top 3 buds at the tip to be sitting above the soil level.
Leaving 1/4 to 1/3 of the tip of the cutting above the surface achieves this, otherwise just leave three buds unburied.
Propagating Cuttings in the Ground Using the Slit Trench Method
- Make a ‘slit trench’ by pushing a spade into soil and rocking it back and forth. In clay soil, add some coarse sand for drainage.
- Insert cuttings 2/3 below the soil, with 3 buds visible. Place cuttings 5cm (2”) apart and press the soil down around them. If using multiple rows of slit trenches, place rows 30cm (12”) apart.
- Water in the soil around the cuttings. The soil will remain damp over the winter period.
- Cuttings will root and be ready to plant next autumn when they are dormant once again, as digging them out of the ground tends to cause a fair bit of root disturbance and transplant shock during the growing season.
Propagating Cuttings in a Pot with Growing Medium
- Fill a pot or other container that has drainage holes with a suitable propagating medium. Materials commonly used as propagating medium are coarse sand, regular potting mix, coconut coir, or blends such as a mixture of one part peat and one part Perlite (by volume), or one part peat and one part sand (by volume).
- Insert cuttings 2/3 below the soil, with 3 buds visible. Place cuttings 5cm (2”) apart and press the propagating medium down around them.
- Water in the soil around the cuttings. Keep the propagating medium slightly damp but do not overwater as this will cause the cuttings to rot. If possible, place the container in a cold frame or greenhouse to speed up the formation of roots.
- The cuttings will be ready to transplant in spring as removal from the pot or container causes less transplant shock for the rooted plants than digging them up from the ground.
How to Propagate Grape Vines from Cuttings
Grape vines can be propagated from hardwood cuttings, using two slightly different techniques, with one of them known as a vine-eye cutting.
- To propagate grape vines, simply take a cutting with 3-4 buds
- Push the cutting into the propagating medium so that two buds are unburied.
How to Propagate Using Vine-Eye Cuttings
It’s also possible to propagate vines form very short cuttings containing only one bud, known as vine eyes.
The advantage of this method is that it’s possible to produce more cuttings from a limited amount of propagation material.
- Make a cut 6mm (1/4”) above a bud, then make another cut 5cm (2”) below it to complete the cutting.
- Push the cutting into the propagating medium so that single bud at the top is unburied.
The disadvantage is that vine eye cuttings with their single bud are less vigorous and do not take root as easily as the longer 3-4 bud cuttings.
Whichever method is used, many vine cuttings can be placed into a single large pot of container, and they can then be potted up separately when they put out their leaves in spring.
It is advisable to allow grape vines to grow in their own separate pots for a year to develop strong roots, so they can then be transplanted in the following spring.
In conclusion, propagation from hardwood cuttings is very simple and straightforward. The cuttings left over from the winter pruning of certain types of fruit trees and all grape vines can be used to propagate them.
If the cuttings fail to strike (produce roots), they can just be mulched or composted, so there’s no waste of valuable organic material.
Happy propagating!