Propagating Hardwood Cuttings
One of the easiest propagation techniques is propagating using hardwood cuttings. The best time for taking hardwood cuttings is from early autumn when the leaves drop to late winter and can be used for propagating grapes, hardy kiwi, currants and gooseberries.
The steps are as follows:
Step 1 – Select cuttings
Hardwood cuttings are taken from deciduous trees and shrubs when they have gone dormant and have no leaves.
Take the more mature woody cuttings that are close to pencil-thickness from the current season’s growth but remove 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 – 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.
Step 2 – Trim cuttings to size
- Make a horizontal cut 1/4” below the lowest bud at the base.
- Find a bud approximately 6-10” away from the base to make the tip cut, a longer cutting stores more food in it which will help keep them alive through the winter.
- Near this tip bud, make a sloping cut away from a bud, 1/4” above the bud.
Step 3 – “Wounding” the cuttings
This involves making an additional light cut on either side of the cut stem at the base to expose more of the cambium and helps to encourage rooting. The cambium is the light green layer under the bark when you scrape it away.
You can scrape off the bark or outer layer to expose the cambium using a knife or the sharp edge of your scissors or snippers.
Step 4 – Dip the base of the cutting into rooting hormone (optional)
Treating cuttings with rooting hormone can increase the chances of stimulating root growth. Dip the base into the rooting hormone, that’s it! If using root hormone powder, be sure to tap the cuttings to remove excess powder.
Step 5 – Prepare propagating medium and insert cutting
The cuttings can placed in the ground in a ‘slit trench’ outside, or they can be placed in a container of propagating medium.
The cuttings can still lose moisture and dry out, even without leaves, so 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.
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.
- Put cuttings in so 2/3 is below the soil, place cuttings 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.
Container and propagating medium method:
- Fill a container (pot) 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).
- Put cuttings in so 2/3 is below the soil, place cuttings 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 of greenhouse to speed up the formation of roots. The cuttings will be ready to transplant in spring.
Propagating Grape Vines
Grape vines have a slightly different technique for hardwood propagation, so I will detail it here.
To propagate grape vines, simply take a cutting with 3-4 buds, and push into the propagating medium so that only two buds are unburied.
You can put many vine cuttings into a single container, and then pot them up separately when thy put their leaves out in spring. It is advisable to let them grow in their pots for a year to develop strong roots, then they can be transplanted in the following spring.