Cutting is a way of vegetative reproduction. Spring and Autumn are the two seasons where cutting can take place in Hong Kong, and it should be finished by the end of November. Let's have a look at the principle and tips for cutting!
What is Vegetative Reproduction?
Unlike seeds which require reproductive organs such as stamen, pistill and ovary, vegetative reproduction needs only vegetative parts such as roots or stems, and even cell for propagation. The herbs we are using today all produce seeds, so why should we do cutting?
The benefit of vegetative reproduction is that it produces plants with identical quality as the parent plant, it is also quicker to grow and bloom. A lot of fruit trees also adopt vegetative reproduction as their propagation method. The disadvantage of vegetative reproduction, though, is that the genetic diversity may decrease and eventually leads to results of crop yield decrease, and less adaptive capacity.
These disadvantage may occur with herbs too, but not as much as fruit trees. If you are looking to propagate herbs which seeds' germination rate can fall easily, such as rosemary, cutting is the best way to propagate - just as we do at The Clover Nursery.
The latest successful cutting of rosemary at The Clover Nursery which will be launched at our online store in a few weeks
Most lamiaceae (mint, rosemary, basil etc.) or apiaceae (dill, parsley etc.) origninates from the temperate climate zone. In Hong Kong, it is best to do cutting at early Spring (March - April) and Autumn (September - November). If you want to do cutting in other seasons, you will need to create the appropriate temperature, humidity and sunlight for rooting.
Ensure the temperature of the growing media is between 20℃ to 30℃.
If temperature is too high, water of the cutting will evaporate easily and die before rooting. If temperature is too low, rooting becomes very slow, and there is the risk of cold damage.
That is one of the reasons why Spring and Autumn are the best seasons for cutting. However, make sure you understand the geographical life cycle of a particular plant. For example, apiaceae usually bloom and produce seeds at around April, and they will not live the Summer of Hong Kong, so there is no point in cuttage. Whereas most lamiaceae, such as basil, mint and rosemary withstand Hong Kong Summer relatively well.
To avoid rapid evaporation of water, which lead to withering of the cutting, make sure a relatively high humid environment is created for the cuttings. If you are working on a big amount of cutting, you may need a mist chamber like ours at The Clover Nursery. Otherwise, use a transparent plastic bag or cup to cover the cutting, so that the microclimate of the cutting will remain moist.
Mist chamber for cutting at The Clover Nursery
Place the finished cutting under indirect sunlight - AVOID DIRECT SUNLIGHT! Just as it is suggested above, we need to aim for slower water evaporation, but also make sure it is not too dark for photosythesis.
Perlite is the best media for cutting because of its ability to retain water and drain excessive amount of water at the same time. It also allows areate, and it is a bacteria-free media produced under high temperature. You can use perlite alone, but you can also mix perlite with peat moss and potting mix, increase the ratio of perlite, and let the cutting to be grown in the mixture. Though you may not be able to observe rooting with this mixture. Rooting from soil requires approximately half a month.
Apart from rooting from soil, you can also perform cutting and allow rooting from water. Most lamiaceae herbs root well from water, and they do live after transplant. Mint is the fastest rooting herb with just 3-5 days, while rosemary is one of the slowest which may take up to 2-3 weeks.
Perlite is the best growing media for cutting
How to do cutting?
Make sure you choose a parent plant that is growing well, and choose cuttings that are
- No pests and diseases
- Not flowering
- Containing both green and lignified parts in a single stem
- Length of approximately 10cm
- With 3 or more nodes, so they can develop into adventitious roots
Remove all leaves at the bottom half of the cutting. To avoid evaporation, you can also trim half of the remaining leaves. Water immediately with spray.
If you chose to root from water, make sure leaves do not touch the water to avoid rot. Change water daily to avoid bacteria.
When white roots are formed and new sprouts are discovered, it is time to transplant. If you chose to root from perlite, you can transplant with the perlite that the roots hold on to. After new shoots start to grow, pinch and let the plant to branch, which will lead to better shape and yield.
Rooting in water is fast and allows you to observe the process
Want to know more?
We are now planning a series of seasonal gardening workshop. If you would like to know more about the content of the workshop, or you are interested in co-hosting a workshop, email us at firstname.lastname@example.org or WhatsApp: 9818 8650!