In the Garden Don’t slip up when growing plants from cuttings
Follow these propagation pointers to achieve the best results in your garden
Growing plants successfully from cuttings is not a matter of having green fingers. It’s purely a case of luck. That was once told to me by a horticulturist who was responsible for cultivating plants from cuttings for a large Eastern Cape nursery.
For this reason it is wise to make more than one cutting of a plant as you are not guaranteed of a 100% success rate.
Unlike a plant grown from seed, cuttings are clones — replicas of the parent plant.
There are a number of plant cuttings which may be propagated from the parent plant. They may be roughly categorised into softwood cuttings, semi-hardwood cuttings and hardwood cuttings.
Softwood cuttings are immature shoot tips which are used to multiply pelargoniums, chrysanthemums and some perennials.
Semi-hardwood cuttings are those which have a firmer growth and are best taken in mid to late summer. They are not as mature as hardwood cuttings.
It happens that now — late autumn and early winter — is the time to take hardwood cuttings and increase the stock of shrubs such as hibiscus, pomegranates, roses, mock orange, abelia, viburnum, hydrangeas, camellia, deciduous trees and others.
Softwood cuttings
Softwood cuttings are taken in the early part of spring before there is any sign of hardening of the new shoot. They are young, soft and green at the tip and base. Take them from the tips of the stems of shrubs or select young growth at the base of perennials.
The size of the cutting depends on the size of the leaf and could be anywhere from 5-10cm in length.
Prepare the growing medium in a pot or an empty ice cream container. It is important that the growing medium is inert/sterile. Options are a palm peat block soaked in water; river sand; polystyrene balls mixed with peat; or equal parts peat and sand.
Don’t add compost or manure to the growing medium, as this will cause fungi to grow causing the cutting to rot.
Remove the lower leaves of the stem, then cut clean across the stem just below the leaf joint (where there is a concentration of the growth hormone auxin and stored food) using a sharp knife. Remove any flowers so all the plant’s energy can go into its root formation.
Sprinkle some growth hormone powder into a saucer and roll the base of the cutting in it. Moisten the growth medium then make holes in it with the back of a pencil. Insert the cuttings into the holes. Spray the seedlings twice a day and when they are looking perky pinch out their growth tip (at the top of the cutting).
Softwood cuttings can take from 10 days to three to four weeks to root.
Hardwood cuttings
Choose stems from this year’s growth which have a pencil thickness and feel woody to the touch. An ideal rose cutting would be a stem which had borne a recently flowering rose which has dropped its petals.
Trim the stem to about 20cm to 30cm. Cut just below the leaf node as it is there that cellular activity is strongest and which aids in the formation of roots at this site.
Cut straight across at the top just above a bud and at a 45-degree angle at the bottom just below a growth bud so you can differentiate between the two sides.
Remove most of the leaves at the top, allowing just a few to remain at the top.
Shave a thin slither from near the base of the cutting to aid it in rooting.
Dig a V-shaped hole in a sheltered spot in the garden and drop in a layer of sand at the bottom. Rest the bottom of the cutting in the sand and fill in around it with the remaining sand.
Make sure you plant the cuttings to at least half their length.
It will take about a year for them to become viable plants so choose the site you plant them in well.
Semi-hardwood cuttings are taken from mature stems of this season’s growth which are bendable but not floppy. They can take from two weeks to two months to take. Examples are the camellia, azalea, leptospermum, magnolia and others.
Decide on the length making sure you have at least one node or more above the growing medium and one below. Remove the leaves from the cutting which will go into the medium. Dip the stem into a growth hormone and then, as directed above, into the hole in the growing medium made with a pencil.
If you were to push the cutting in to the medium without making a hole with a pencil first, the growth hormone would be rubbed off the cutting as you inserted it into the soil.
General tips
Honey is a good fungicide. Dip the base of the cutting into the honey. To test if roots are forming, gently do the “tug test ”— carefully tug at the plant to see if the roots have grown and secured it into the growing medium.
“In the Garden” is written by feature writer, garden enthusiast and former teacher Julia Smith, who has returned “home” to live in Chintsa East. The column looks to inform both novice and accomplished gardeners how to make the most of their green patches.