Fertiliser

Once in the pot, the nutritional content of the soil on its own is often not able to satisfy bonsai requirements to grow strong and healthy trees. For this very reason, bonsai enthusiasts regularly use organic or inorganic fertilisers, liquid or solid, pre-made or personally mixed depending on their preferences.

Your bonsai will need seventeen very important nutrients, which are divided into macronutrients and micronutrients. The nutrients include calcium, magnesium, zinc, and iron, to name a few, and they will be absorbed by the tree through the soil.

While the micronutrients are required in very small quantities (one part per million), and trace elements of the most important are usually contained in fertiliser products, the macronutrients are the ones that we are after. Specifically, we’re looking for nitrogen, phosphorous, and potassium. These are often highlighted on fertiliser packaging as NPK with their quantity (for example, N-P-K 4-5-4). These three macronutrients are responsible for the vigour of the tree, the colour of the leaves, the health of the roots, and the fruit and flower production, along with resistance to diseases.

It is important to choose a well-balanced fertiliser that is not too high or too low in these nutrients. Overfeeding may burn the root system or unbalance the growth of the tree and leaves, which we aim to keep at a certain size. Alternatively, there may be enough to keep the tree healthy because it will not be able to withstand the poor nutritional environment.

I personally use liquid fertiliser from spring until the end of summer and then apply solid pellets in autumn and, in some cases, winter. I look for the following proportions depending on my trees’ needs, the season, and the specimen:

  • N-P-K 6-3-6
  • N-P-K 4-5-4
  • N-P-K 5-3-5.

The feeding period commences with the start of the growing season (the end of March), and I feed at regular intervals of at least once every two weeks. The gap increases to once a month in autumn, and then I stop feeding in the winter when the tree starts its dormancy phase (except for indoor bonsai, which I continue to feed).

I hope that this guide for feeding frequency, timing, and portion gives you a starting point to approach this task. Along the way, you will make your own adjustments and improvements to suit your trees.

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Gardenia

Family: Rubiaceae

Genus: Gardenia

Botanical name: Gardenia Jasminoides

Found in tropical and subtropical regions, the Gardenia is a genus of over 200 species belonging to the Rubiaceae family. Native to Asia, the Gardenia jasminoides is an evergreen specimen with shiny lanceolate leaves, and it is well known for its beautiful and perfumed white flowers that bloom in the summer. This attractive little shrub with grey bark is excellent indoor bonsai material in temperate zones.

Gardenia media

Style

The Gardenia seems to be adaptable to most bonsai styles, both formal and informal, such as upright, slanting, broom, and so on.

Locations and Positions

From spring to the end of summer, your tree can enjoy being kept outdoors in semi-shade When the temperatures drop below 15 degrees, relocate it indoors by a south-facing window

Watering

The Gardenia has similar necessities as Azaleas or Syzygium. Keep the soil moist, possibly with rainwater, and avoid long periods of dryness or soaking wet conditions.

Feeding

From growing season to autumn, feed your gardenia every two weeks with a liquid fertiliser for ericaceous plants (acidic-loving plants), and reduce it to once a month during the winter.

Pruning and Pinching

Wait for flowers as you would do with the Azaleas. Remove the flowers, and then you can start to shape by pinching back the new growth or attempting structural pruning.

Repotting and Soil

The Gardenia jasminoides can be repotted every two years or as soon its roots fill the pot in early spring. Use acidic soil, such as Kanuma or a soil mix suitable for ericaceous plants. Ensure that the mix you use creates a well-drained environment for the tree.

Wiring

By the end of the summer, the plant will still be quite flexible, and growth will slow down, making it the perfect time for wire application.

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