Getting Started with Bonsai - A Growing Guide

Bonsai cultivation has a long tradition in Asia. These plants are family treasures many decades old. However, you don't need to be intimidated - even one year is enough to grow a beautiful tree.

How to start and what to expect - we bring you this in the following bonsai growing guide.

You will read here: what to consider - substrate - repotting - bonsai types - shaping - watering - leaf trimming - fertilizing - overwintering

What to consider:

Before you get a bonsai for your home, you need to answer several questions. While the plant isn't as demanding as a pet, for example, it still needs care. And last but not least, you need to choose the type of bonsai that will be suitable for you.

1. Will I have time to care for a bonsai?

While you don't need to prune and repot the tree every day, you need to realize that you'll probably be growing it in a very small and very shallow pot. Especially smaller bonsai placed outdoors need watering at least once a day. So if you're in the habit of going away for weekends and holidays, you need to find someone who will take care of your bonsai while you're away.

2. Do I have space for a bonsai at home?

If you get a tree, you should choose a suitable location for it. In the case of an indoor bonsai, a window is best suited for this purpose (western or eastern windows work best), if you're planning to have an outdoor bonsai, it should be a place with sufficient light, but preferably without direct midday sun.

3. How large a bonsai would I like?

The term "bonsai" doesn't only include trees a few tens of centimeters tall. A bonsai can be up to two meters tall. It depends on each grower's taste and space possibilities. According to the desired size, you need to choose a species that grows either quickly or slowly. If you're planning a larger bonsai and don't want to wait several years for it to grow, it's advisable to buy an already larger tree, or a plant pre-shaped for growing as bonsai.

4. What species to choose?

The choice of tree species depends on what your final vision is. Bonsai can be grown from almost anything that forms woody tissue.

For outdoor bonsai, deciduous species are rather recommended for beginners. Miniature pines may look beautiful, but they are really demanding.

Beautiful bonsai can be created, for example, from hornbeams, lindens, maples, or fruit trees. Flowering bonsai from lilacs, azaleas, or fuchsias also look beautiful. When growing ornamental apple or cherry trees, they will additionally reward you in summer with beautiful-looking fruits.

There are many possibilities. However, you should rather avoid growing bonsai from oaks if you want your tree to have small leaves proportionate to the plant's size.

When growing indoor bonsai, you can choose from all kinds of woody species that are cultivated as potted plants.

Very rewarding and resilient options include, for example, ficus (benjamina, ginseng or retusa), Ligustrum (privet), Chinese elms or jade plants. What's pleasant about these species is that they're evergreen year-round, so they can continuously decorate your home.

Succulent species and ficus appreciate plenty of light, they're happy even with a south-facing window and summer outdoor placement in direct sun. Moreover, they can tolerate occasional neglect of watering. Some species, such as pomegranate, also bloom beautifully and can reward you with fruits.

5. Where to get a bonsai?

There are several ways to acquire your own bonsai. The simplest, but also most expensive option is to buy a ready-made bonsai or pre-styled tree in specialized shops. The bonsai looks attractive from the start and you can maintain it in approximately the same shape. However, you won't experience the joy of growing and shaping it from the beginning according to your own vision.

A cheaper alternative for growers who are really serious about their passion is to grow a bonsai at home. It doesn't require much effort, but it does take time.

Another option is to buy a classic unstyled tree, or dig up a suitable plant directly outdoors. You'll have a more mature plant, but you'll need to prune and shape it yourself. The root system will also need to be adapted to the new pot in several stages. With this method, you'll truly feel the joy of your own work's results. This approach is suitable for anyone who wants to shape the entire plant with their own hands but doesn't want to wait long for the tree to grow sufficiently.

When buying trees, pay special attention to ensure they're healthy and free from pests. It's better to avoid plants with spots on leaves, dead roots or shoot tips.

The final option is to grow a bonsai directly from seed. It's a lengthy and laborious method, but achieves the best results. You have control over the plant throughout its entire development. If you want to grow miniature bonsai up to ten centimeters in size, this method is probably the best.

Once we have the bonsai

After purchase

When you bring a plant home from the shop, it's usually best to repot it right away. This especially applies to indoor plants that weren't purchased from a specialized bonsai shop. The substrates are often unsuitable, retaining too much water and leading to root rot. If you have a plant dug up outdoors, it's better to gradually acclimate it to pot cultivation - trim thick roots and plant it in an appropriately sized ordinary pot

Substrate Selection

There are special substrates suitable specifically for bonsai. They can be purchased at various grower supply stores. The substrate is sufficiently airy to encourage the formation of as many fine roots as possible, doesn't retain too much moisture to prevent root rot, and also contains the necessary nutrients that will last the plant approximately six months of growth. Fired clay substrates (most commonly Akadama) have also proven effective - they look like small granules and are optimal for root growth, but contain no nutrients, so these need to be added through watering.

Pot Selection

There are as many styles and types of pots as there are bonsai growers. Pots can be shallow or deep, plastic, ceramic or stone - it all depends on taste and the size and type of bonsai.

If you want a classic, upward-growing bonsai, a shallower rectangular, oval or round pot is probably the best solution; deep pots are used more for creating cascades.

What all types of pots should definitely have are sufficiently large drainage holes. Most houseplants don't die from drought, but on the contrary from overwatering, where the roots rot and the plant dries out.

It's best to choose a pot with a matching saucer to catch excess water.

Repotting

Before we start repotting the plant, we'll prepare everything in advance. We'll need a pot for the bonsai, or a planter (if you're reusing an old pot, don't forget to scrub and disinfect it thoroughly), substrate (possibly mixed with fertilizer), a wooden stick for separating roots, wire for fixing the plant (preferably aluminum), tools for pruning roots, and possibly a mesh for drainage holes (we can use a piece of old curtain or other similarly loose material).

We'll place the mesh over the drainage holes and secure it with pieces of wire. This will prevent substrate from washing out. We'll also thread wires through the drainage holes, which will later serve to firmly secure the bonsai in the pot. The wires should stick out with four ends from the pot.

When repotting bonsai, we have the opportunity to examine and prune the roots.

First, it's necessary to remove all the old substrate clinging to the roots. The best approach is to rinse the roots with water after mechanical shaking and root separation (you can use a wooden stick to help). The water shouldn't be too cold; settled or rainwater is best. Then we can start working with the roots.

The ideal is a dense network of fine roots and root hairs; thick roots should be removed. It's not always possible to remove all thick roots at once - for plants from the wild or those grown in large containers, root pruning is done gradually over several repottings.

When removing excess roots, pay attention to the cleanliness and sharpness of your tools, and treat larger wounds (for example with grafting wax).

Remember that there must always be enough roots left to sustain the plant.

If the plant exudes latex (a milky-colored sticky substance), spraying the wound with cold water helps - the latex will coagulate and the plant will stop "bleeding."

When pruning roots, it's good to keep in mind the future formation of nebari - the part of the trunk that transitions into roots. This transition should be nicely smooth. Several larger roots should therefore be left for this purpose. We spread these main roots flat, as they will lie in the pot. This also depends, of course, on the type of pot we'll be planting in.

If the roots don't stay in place as they should, we can use wire - either wire specifically made for bonsai, or any other sufficiently flexible wire of adequate thickness. Copper wire is not suitable as it inhibits root growth.

Basic Shaping

Finally, we get to how to actually shape the plant so it looks like an ancient, gnarled tree. There are several types of bonsai shaping, with the most commonly used being pruning and wiring.

Before starting to shape, you need to select the viewing side, the one you'll look at most often. Mentally or on paper, create an ideal image of how your bonsai should look. You must take into account its disposition, because while we can cut off a branch, we cannot force it to grow. You can try bending them by hand to different angles. None of the branches should stick out directly toward you from the viewing side. Once you have a clear vision, it's time to start shaping.

Remove excess shoots right away, shorten those that are too long or insufficiently branched. Treat cut wounds with grafting wax.

For the actual shaping, we use wire. It's best to buy wires specifically for bonsai - they hold their shape well and don't damage the tree's bark. We need wires of various thicknesses.

When wiring, we proceed from the bottom of the tree and from the strongest branches to the weaker ones, choosing wire that will hold the branch in the desired position and bend, but isn't unnecessarily thick.

We wind the wires at approximately a 45-degree angle. We attach each wire to the trunk or to a stronger branch, from where we then wire onto weaker ones.

Only after we have wired the entire tree do we proceed to the actual shaping. We work again from the bottom up, branches should not overlap or cross, and buds should face outward from the center. For larger bends, it's good to first gently flex the branch with your fingers in all directions.

Proceed carefully so the branches don't crack.

The wires remain on the bonsai long enough so that after their removal, the branches and trunk maintain the desired shape. This can take several months, or even a year. During this time, care must be taken to prevent the wires from pressing into the bark or even growing into it - this would cause unsightly scars, like those you can find on industrially grown "bonsais" in department stores. Species with soft bark, such as ficus trees, are particularly susceptible to wire pressure. If the wire is already too tight for the plant, there's no choice but to unwire it and wire the plant again.

Watering Bonsai

Bonsai usually grow in shallow dishes, so they need to be watered frequently during the growing season. Most need watering at least once a day. Rainwater is best, but settled tap water can also be used.

Bonsai must be fertilized, especially after they deplete the fertilizer contained in the substrate (at the latest after half a year). From spring to mid-autumn, they should be fertilized once every 1-2 weeks. There are fertilizers designed specifically for bonsai available on the market, but you can also use standard fertilizers.

During winter dormancy, either water almost not at all (deciduous overwintered species), or water only enough to prevent the substrate from drying out too much, and fertilize once every 2-4 weeks (for indoor evergreen bonsai).

Leaf Size Reduction

Some tree species naturally have small leaves, while others become smaller on their own when grown in containers. However, for most trees, we can help reduce leaf size. This process is called defoliation. It's performed only on healthy, well-rooted trees during the growing season.

Before performing defoliation, it's advisable to thoroughly fertilize the bonsai so it can produce new leaves without becoming weakened.

You may notice that trees browsed by wildlife produce lots of small leaves and branch beautifully. We can achieve this state artificially as well.

During defoliation, leaf blades are removed (they can be cut off with scissors, but it's good to leave the petioles to avoid damaging the buds and bark). We leave approximately every seventh leaf on the tree, or cut off only part of it. At the same time, we can prune the plant.

Then we move the bonsai into direct sunlight, so the young leaves get accustomed to it from the start. Soon the plant will be covered with new leaves, which should be noticeably smaller and brighter green than the previous ones.

Overwintering and Summering

Outdoor bonsai need to be placed in a cool location for winter. This also benefits some indoor species, which typically require temperatures around ten degrees Celsius. For outdoor species, temperatures can be lower, but the substrate with roots must not freeze. Deciduous species don't need light in winter. Insulated attics or garages are ideal. Excessive moisture is undesirable, as it favours various fungal and bacterial pathogens.

In spring, when night temperatures no longer drop to zero, we can move the plants outdoors again. This is also a good time to repot into fresh substrate and prune. First, it's advisable to leave the plant in partial shade for a few days, then it can be placed in full sun.

Indoor bonsai also benefit from time outdoors in the sun. We can usually put them outside around mid-May and they can stay there until mid-September. Temperatures shouldn't drop below ten degrees Celsius, though this depends on the specific species (for example, ficus trees don't like temperatures below 15 degrees, but Chinese elm tolerates temperatures down to four degrees).

Fertilising

We fertilise bonsai with special fertilisers according to the manufacturer's instructions. Liquid fertiliser with an NPK ratio of 4-3-9 is very suitable. This ratio is often found in bonsai fertilisers.

Reduced nitrogen content in the fertiliser supports the growth of leaves and needles. Less nitrogen is needed precisely for the compact appearance of bonsai and smaller leaves.

Dosage: 15ml of liquid bonsai fertiliser is diluted with 5l of water. It's recommended to fertilise throughout the entire growing season, from April to September. Feed once every 14 days, and once a month during the dormant period.

Read also: How to Maintain a Healthy-Looking Bonsai