Basil Bonsai? What is That? Can You Really Grow It?


Recently, you have been introduced to the wonderful world of bonsai and the possibilities for its application to herbs. Why not turn your basil plant outside into a fancy bonsai? Is it really possible?

Basil can be turned into bonsai. However, such bonsai will last only one season. There are 5 basil varieties that can be turned into bonsai: 1) Bush, 2) Camphor, 3) Opal, 4) Lemon, and 5) Cinnamon. 

As soon as I heard about this, I immediately set about my research. You can read all about it below.

What Is Basil Bonsai?

Basil bonsai is just the basil herb that is developed into a bonsai tree. There are 2 ways that basil bonsai is developed, from seed or cuttings or through grafting into a bonsai trunk.

Many basil varieties as you may know are annual herbs — they are grown in the spring and die as soon as the first frost arrives. Due to this nature, it is cultivated into bonsai to be able to harvest fresh basil for longer than a year.

The practice of growing bonsai started in China and was exported to Japan where it became a form of art. Indeed the word “bonsai” comes from the Chinese word, “pun sai” which means “tree in a pot” or for a more descriptive term, “miniature tree in a pot.” 

It was the Japanese gardeners who developed ways of making bonsai trees look natural and aged. Over time, they developed rules which became standards for what the classic bonsai style should look like.

Basil Varieties That Can Be Trained Into Bonsai

Not all basil plants can be turned into bonsai. This is because for a bonsai to grow successfully it needs to have a leaf to stem proportion and ideally be a perennial variety. 

Many people make the mistake of thinking that growing bonsai needs “dwarf” or naturally small trees or special trees. However, this cannot be far from the truth. 

What many bonsai growers tell us is that what makes for a successful bonsai culture is that all the plant parts are proportional (balanced or in harmony) to the size of the tree and the pot it is planted in.

Therefore, to be successful, the plant you choose to develop into bonsai should have the following characteristics:

  • Small leaves or leaves that shrink as it is being cultured into bonsai.
  • A short distance between leaf nodes.
  • Attractive bark or roots.
  • Good branches for nice forms.

Taking into account the characteristics mentioned above, we can rule out, for example, Lettuce leaf basil (O. basilicum ‘Crispum’). Its large leaves will make the mature plant look disproportionate to the overall tree structure.

Also genovese basil is not suitable as it is an annual variety.

Important note:

These varieties of basil are perennial only in a warm/tropical area. If this is not your case you should bring it inside during the winter and use some supplementary grow light.

1 – Bush basil (Ocimum basilicum minimum) 

This is the best variety to use because it has small leaves and has a small size. At maturity, it reaches 18 inches (46 cm) in height making it perfect for growing in a minimum of  4 inches (10 cm pot).

2 – Camphor basil (Ocimum kilimandscharicum)

Bonsai are grown in pots and what makes this basil a good candidate is that it is recommended to grow it in a pot at the outset. Camphor basil will suffer transplant shock when planted from the garden to a pot. 

This basil is classified as a perennial which means it can grow again in the spring. It is woody, has a strong camphor odor, has ovate leaves, produces white creamy flowers, and grows up to 47 inches (120 cm). 

Camphor basil’s flavor is too strong hence it is not recommended for culinary use but it can be used as a natural insect repellent. Also, should you develop it into bonsai, it would look good as an ornamental.

3 – Opal basil (Ocimum basilicum ‘Purpurascens’)

Its other names are Dark Opal basil and Purple basil. Its color and appearance make it exotic and attractive when miniaturized. 

It is a great specimen for bonsai because it is bushy and has small but broad dark purple/maroon leaves. During the flowering season, it bears long tubular spikes of lilac/pink flowers.

It grows up to 20 inches (50 cm) in length and has a width of 18 inches (30 cm). Its lifespan is between 1 to 2 years. 

4 – Lemon basil (Ocimum basilicum citriodorum)

This very fragrant basil came from Thailand and was introduced in the USA by the Department of Agriculture around 4 decades ago. It is annual basil which has a shorter height of 18 to 24 inches (46 to 61 cm) that is perfect for container gardening. It can thrive at the minimum temperature of 40 to 50 °F (4 to 10 °C).

The leaves have a strong lemon taste that greets your nostrils as soon as you enter the space where this plant is set. Its culinary uses are soup flavoring, sauce, and fish and meat dishes. 

 5 – Cinnamon basil (Ocimum Basilicum cv) 

It’s also known as Sweet Basil ‘Cinnamon’ and Mexican Spice Basil has a spicy flavor and an aroma that reminds you of incense. This plant is classified as a perennial but grown as an annual. 

It is grown for its leaves but can also serve as an ornamental plant. At maturity, it reaches a height of between 18 to 30 inches (45 to 75 cm) and a spread of 18 to 24 inches (45 to 60 cm).

How Long Does Bonsai Basil Last?

Here you need to be careful. The average lifespan of bonsai basil is 3 years and depending on the level of attention and care, it can last longer. So, if you are not using perennial basil like Camphor basil and Cinnamon basil, the lifespan can be shorter. For example, the normal genovese basil (not adequate to be turned into a bonsai) only lasts a season.

People who are new to bonsai culture can easily learn this art with the use of herbs such as basil or rosemary for practice. Unlike other plants that are traditionally used in bonsai development, herbs are readily available and cheaper.

Another advantage with using herbs is that it grows fast. Within 3 to 6 months, you can have basil bonsai that looks like the equivalent of a mature bonsai plant.

Why Do Basil Bonsai Develop A Trunk?

Some basil plants naturally develop a woody-like trunk. To note, this will not be the turn of a tree. It is just a very woody stem. This is a natural part of the aging process and the basil’s way of hardening or preparing itself for the coming of the cold temperatures. 

There are techniques to prevent woody trunks if this is a big of an issue. However, in training bonsai, a woody gnarly trunk is encouraged as it is one of the characteristics that make bonsai look aged.

Two Ways To Start Basil Bonsai 

Basil bonsai can be developed from 1) seed 2) cuttings.

1- Growing From Seeds

Starting from seed is the best although the hardest way. If you start by planting in the garden you can achieve faster growth, better looking, and thickened trunk in this way.

2 – Growing From Cuttings

As for cuttings, start with cuttings 3 to 6 inches (8 to 15 cm) long with leaves from the lower half removed. Soak the stems in a rooting medium for 6 to 12 hours then stick them in a shallow pot with 1 part perlite, 1 part vermiculite, and 4 parts coarse builder’s sand.

The Importance of Trimming in Basil Bonsai

Imagine the final shape of your bonsai basil. Trim your plant up to its basic skeleton: a trunk and a few branches (3 to 4) based on what you imagine the growth pattern will be. At this point, your plant will look bare and it can take 6 months or more to develop a nicely shaped crown.

The basil needs to be trimmed several times as the basil grows. If you planted your basil in the garden, you can start the trimming and shaping before you transfer the basil onto a pot. 

At the end of the growing season, you will end with a basil bonsai that looks “finished” i.e. looks like an aged, mature tree, trimming should be done up to two times during the growing period, i.e. summer.

In the midseason, the herb will be vigorously growing and you will notice many shoots coming out on the parts that were trimmed down. If the new shoots reach 6 to 12 inches (15 to 30 cm), trim them again. 

Trimming at this time is done to direct the growth of the crown. 

Grafting a Bonsai Plant

This is something I never did myself, but it can theoretically be possible to graft a basil plant into another. This is very common for cacti.

Grafting is a plant cultivation technique where 2 plants are joined via their vascular tissues so that they can continue to grow together. There are mainly 2 things required in grafting: 1) the rootstock, and 2) scion.

1 – Root Stock

It is the root portion of a grafted plant. 

2 – Scion

This is the part that is being grafted into the rootstock. It is selected for its stem, leaves, fruit, or flowering characteristics.

Gardeners and farmers have been using grafting techniques to produce trees that bear fruits of another plant or other varieties combining the good characteristics of both plants.

In the case of basil bonsai, the top leaves (scion) stem is grafted into a sturdy trunk (rootstock) to keep basil alive longer and continue production for a longer period.

Basil Bonsai Caring Tip

Here are 9 general tips on how to care for basil bonsai for those who are new to the art of developing bonsai from herbs.

1 – Repotting

Some gardeners like to start their bonsai candidate plant in the garden to transplant later when the basil reaches the right height or maturity. Some like to start in pots to prevent transplantation shock and some do a combination of grafting and then repotting.

When repotting basil bonsai, prune the leaves at the crown first. This balances the water loss by decreasing water uptake from the roots.

If you decide to do a grafting/transplanting combination, the recommendation is to use extra care that the part where the two plants meet remains above the soil line. 

This is to prevent the scion (the top plant) from growing new roots and falling back to its original state. If necessary, support the spliced stem to keep them from falling apart.

2 – Lighting

Traditional bonsai plants are always left to continue growing outdoors. Bonsai are only taken indoors for certain amounts of time to display and then taken back outdoors. 

Basil bonsai, just like ordinary basil in pots, are taken indoors in the winter to prevent it from dying. For indoor settings, lighting is critical.

While the best lighting setup is a well-equipped greenhouse or a solar room, many gardeners report success placing basil bonsai near the windowsill.

3 – Rotate the Tree

A plant’s branches or leaves have the tendency to turn towards the light source. If you place your bonsai basil near the windowsill, remind yourself to turn it regularly so that it will have balanced growth.

You can also opt to balance the unidirectional light coming from the window with an inexpensive lighting setup. For example, you can use a small grow light that is between 75 to 100 watts which you can screw into an old lamp placed 4 to10 feet away from the bonsai.

4 – Potting Soil

According to the author and professional herbal bonsai grower, Richard W. Bender, potting soils are not as critical as lighting conditions for basil bonsai. In his opinion, basic houseplant soil with perlite or very small rocks will improve the water drainage capacity of the soil.

5 – Pots

Traditional bonsai pots are shallow and should not be deeper than the diameter of the trunk. This only works for bonsai that have been trained for years because they are mostly slow-growing. 

For herbal bonsai, deeper pots are needed because as I have mentioned earlier, herbs grow faster and need a lot of room to spread their roots unless you are the type who likes to repot regularly.

6 – Fertilizers

Feeding is paramount for basil bonsai to have an abundant harvest. Some gardeners use a time-release fertilizer while some top-dress their soil with fertilizer.

It should be done regularly during the early up to the mid-growing season. Fertilization should be lessened as the end of the growing season draws near.

Once a month application of a mild fertilizer is enough. Fish emulsion is great although I’m told it does not have the most pleasant of odors. 

7 – Pruning/Harvesting

Pruning is an important step to keep the shape of the bonsai basil even and healthy. Also pruning flowering spikes helps to keep basil from seeding.

It is recommended to harvest leaves from the bottom stems so that eventually, a dome-shaped top will be achieved. 

Basil can grow quickly out of hand and lose its shape because it grows fast. When this happens, it is recommended to cut it back sharply down to the woody stem and let it sprout again.

Root pruning restricts plant growth tremendously. In traditional bonsai development, this is done to plants that would normally grow several feet in its natural environment. It is also done for aesthetic purposes i.e. give the appearance of an aging plant. With herbal bonsai, this will not be necessary if you are going to use deeper pots.

8 – Watering

The recommendation is to follow the watering schedule as prescribed for the variety of basil bonsai you have.

Wet-dry cycles negatively affect basil bonsai. To prevent water loss due to evaporation during hot days, mulching is recommended.

9 – Bring Basil Bonsai Outdoors

As soon as the weather allows, bring the plant outdoors. This is actually true of most plants, not only of basil. Natural sources of light and wind are always good for plant growth. 

However, if you live in areas where you’d get a lot of intense heat from the sun, place your bonsai basil in a place where it is shaded during midday to prevent it from sunburn and drying out too much.

Israel’s Basil Tree

Example of Basil bonsai Will Look Like – Infographic

A company in Israel called Hishtil developed two new strains of basil they named Basil Tree (FuntaStick Ocimum ‘Basil Tree’ and FuntaStick Ocimum ‘Basil Tree’ Red). The trees were developed from two undisclosed types of basil. One of the basil grows a trunk and the other one is of the aromatic and leafy variety. 

The idea is to grow a new type of basil that has solid roots so that new leaves could sprout regularly. To achieve this, the basil varieties were grafted and allowed to take root inside the trunk of another plant. 

Growing basil every year can be tiring especially if you are in a business that regularly uses fresh basil. So what this company does is sell the Basil Tree as a fully matured over 18 inches (40 cm) tall ornamental herb that is not only pest resistant, disease tolerant, weather resistant, but also drought tolerant.

The tree looks like a leafy shrub that has a dark green/reddish color foliage. It flowers during summer and produces dark purple blooms that are perfect for pizza, salads, and pasta.

An Hishtil executive describes the Basil Tree as an “in and out” plant because it is supposed to be taken outdoors during summer and taken indoors in the winter.  The minimum temperature needed for growth is 54°F (12°C) at night and 61°F (16°C) in the daytime. Following the recommended care they expect the plant to survive 5 years.

Takeaways

  1. It is possible to extend the life of annual basil by cultivating it into a bonsai plant.
  2. Bonsai basil can be done two ways: from seed or cuttings and grafting.
  3. Basils that grow woody trunks are good candidates for bonsai development because gnarly stems are one of the characteristics of traditional bonsai culture.

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Sources

“Herbal Bonsai Practicing the Art With Fast Growing Herbs” by Richard W. Bender (ebook)

“Bountiful Bonsai” by Richard W. Bender (ebook)

“Growing Bonsai” by n.a. in British Bonsai 

“Basil, Bush (Ocimum minimum)” by n.a. in Norfolk Herbs 

“BASIL – CAMPHOR” by n.a. in Mountain Herb Estate 

“Ocimum basilicum ‘Dark Opal’ (Basil ‘Dark Opal’)” by n.a. in Shoot 

“Lemon Basil (Ocimum basilicum citriodorum)” by n.a. in My Garden Life 

“Ocimum basilicum ’Cinnamon’ (Cinnamon Basil)” by n.a. in Gardenia 

“Basil Bonsai – You Can Grow That!” by n.a. in Gardening Jones 

“Sweet smell of success wafts from Israel’s ‘Basil Tree’” by David Shamah in The Times of Israel 

“Basil by the tree-ful” by Karin Kloosterman in Israel 21C 

“Ocimum herbalea ‘Red Ball- Bonsai’ Grafted” by n.a. in Hishtil

Andrea

A young Italian guy with a passion for growing edible herbs. After moving to the UK 6 years ago in a tiny flat, it was impossible to grow herbs outside. So I start my journey in growing indoor and so I decided to share my knowledge.

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