扦插是無性繁殖的其中一個方法。春秋兩季是香港適合扦插的季節，秋季大約於12月前完成。今天就讓我們看看香草扦插的原理和技巧吧。

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!

什麽是無性繁殖？
What is Vegetative Reproduction?

相對於種子通過雌雄蕊、子房這些授粉結子的有性繁殖過程，無性繁殖只需要植物的營養器官，甚至細胞就可以繁殖。我們常用的香草植物都是會結出種子的，那爲什麽要進行扦插？

無性繁殖的好處是，下一代能夠遺傳母株的特性，並且縮短生長期，提早開花、結果。例如果樹就很多時候會利用扦插的方式繁殖。不過，長期無性繁殖也有缺點。無性繁殖之下，基因遺傳單一，子代有可能對環境變動的適應能力減弱。

香草雖然也有可能出現這些無性繁殖的缺點，但相對果樹的影響不大。對於一些種子發芽率下降速度快的品種，例如迷迭香，在高華花園就經常以扦插方式進行繁殖。

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.

最近在高華花園扦插完成的新一批迷迭香，再過幾個星期會再次推出
The latest successful cutting of rosemary at The Clover Nursery which will be launched at our online store in a few weeks

香草的扦插 Herb Cutting

大部分唇形科（薄荷、迷迭香、羅勒等）或繖形科香草（蒔蘿、番荽等）屬於溫帶性植物，在香港，早春3-4月，或秋季9-11月進行扦插最爲適當。若你希望在其他季節進行扦插，就必須創造適合的溫度、濕度、光照，才能確保順利發根。

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. 

溫度 Temperature

插床溫度於20-30℃之間。
如果溫度太高，插穗的水分容易消耗，較容易枯萎。
如果溫度太低，發根速度慢，有可能未發根就已經凍傷腐爛。

所以春秋兩季是香港最適合扦插的時期。不過也要注意植物的地區特性，例如繖形科香草在香港幾乎都不能越夏，在4月左右開花結子就會枯萎，所以不太適合扦插。唇形科香草如羅勒、薄荷、迷迭香的越夏能力較高。

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.

濕度 Humidity

為避免水分快速蒸發，導致扦插後的植株枯萎，扦插期間需要保持很高的空氣濕度。高華花園由於需要大量扦插，會設置噴霧系統以維持濕度。如果你在家中進行少量扦插，可以使用透明塑膠袋或杯子覆蓋扦插後的植株，減緩水分蒸發的速度。

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.

高華花園用以扦插的噴霧室
Mist chamber for cutting at The Clover Nursery

光照 Sunlight

把植株置放於散射性陽光下，避免直射陽光。與濕度控制同樣道理，這樣做是爲了減緩水分蒸發的速度，但同時需要確保有一定的光綫，才能進行光合作用

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.

介質 Growing Media

珍珠岩同時具備排水和保水的特性，而且通氣、經過高溫燒成而形成無菌介質，所以是最適合扦插的介質。你可以只使用珍珠岩扦插，也可以使用珍珠岩、泥炭苔、有機物泥的混合介質，提升珍珠岩的比例，讓插穗在介質中持續生長，但這個方法較難以觀察根部是否已經形成。土培大概需要半個月時間。

除了以上土培方式，你也可以先用水扦插（水培扦插）。大部分唇形科香草在水中都非常容易發根，定植後的存活率也高。薄荷是所有香草裏最快的，大概3-5天就會發根；迷迭香則是較爲慢的品種，大概需要2-3星期。

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. 

珍珠岩是最佳的扦插介質
Perlite is the best growing media for cutting

扦插該怎樣進行？
How to do cutting?

插穗應選擇生長旺盛的母株，剪取

• 無病蟲害
• 沒有開花
• 同時具有淺綠色嫩枝和木質化部分的枝條
• 長度為10cm左右
• 枝條會在節位上長出不定根，所以最好有3個以上的節位。

扦插時，摘除植株下部節位的所有葉片，只保留上半部分 ~ 3分之1 部分的頂端葉片。爲了減緩水分蒸發，上部葉片也可以修剪掉半片。扦插完成後，儘快澆水。如果以噴霧或噴水壺澆水，效果更佳。

如果你選擇進行水培，必須注意葉片不能浸在水中，這樣會令植株霉爛。每天換水，確保不會有細菌滋生。

當你發現白色的根系形成，開始長出新芽，就可以把植株定植到田或盆栽中。珍珠岩扦插，可以連同黏著的珍珠岩一起移植。移植後，新芽長出，就可以進行摘心，讓香草植株分枝，形態更美，長勢也較好。

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.

水培扦插速度快，可以觀察根系發展過程
Rooting in water is fast and allows you to observe the process

你是否想知道更多扦插技巧？
Want to know more?

我們正在計劃一系列種植相關的季節專題工作坊。如果你希望知道更多工作坊的内容，或有意合作舉辦工作坊，可以電郵：cs@cloverseedretail.com.hk 或 WhatsApp：9818 8650與我們聯絡！

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 cs@cloverseedretail.com.hk or WhatsApp: 9818 8650!