How to Tell If a Bonsai Is Healthy - Common Issues and Care Mistakes

How to Tell If a Bonsai Is Healthy? Discover Common Signs and Issues!

Bonsai trees are gorgeous, but also require attention and care to stay healthy and thrive. Actually, they need lots of care to stay alive. In this post, you will learn what a healthy bonsai looks like, how to tell if a bonsai is healthy, signs of an unhealthy Bonsai, signs of pests and diseases, how to make and keep a bonsai tree healthy and what to look at when buying a Bonsai tree.

If you are a Bonsai artist, you might be concerned about the unusual changes in the growth and physical appearance of your tree. How will you identify that your artistic tree is having a problem? Do you know what types of pests and diseases can affect Your Bonsai? Or maybe you have not provided it with optimal growing conditions?

But there’s no need to worry. In this post, you’ll learn all about:

  • The signs of a healthy Bonsai
  • Common pests and diseases in Bonsai
  • Bonsai care guide and how to keep Bonsai healthy

A healthy Bonsai has a uniform distribution of leaves throughout the plant. The trunk is thicker at the base and becomes slender towards the top. The leaves are dense, healthy, and bright green in color. An unhealthy Bonsai exhibits disease symptoms such as leaf drooping, wilting, dried foliage, poor anchorage of roots, and falling leaves.

If you notice these symptoms, seek expert advice as soon as possible. Growing a miniature tree is all about the art of patience. It may take almost 10 to 14 years to grow in a full-sized tree. To ensure faster growth of your tree, you have to provide ideal growing conditions.

So, keep reading to explore facts about a healthy Bonsai.

How to Know If Your Bonsai Tree Is Healthy?

You might have admired other Bonsai artists with how they manage to get a healthy and styled Bonsai. Before buying a full-grown miniature tree from the nursery, you should look for the following points to determine whether a Bonsai is healthy or not. Or, you can assess your own tree you already have at home.

  • The branches should be well ramified and distribute evenly throughout the tree. Plus, the roots should not cross each other.
  • Bonsai have surface roots that spread in all directions. The roots should securely be attached to the pot.
  • The leaves should be bright green. Drying and yellowing of leaves mean that the tree you’re buying may be problematic.
  • The trunk should have a smooth surface and look strong. It should be thicker at the base and gradually become thinner towards the top.
  • Branches must not bend on themselves and seem soft: on the contrary, healthy branches break easily.

 Bonsai tree may be unhealthy if you notice the following signs:

  • If the leaves have rough edges and unattractive spots on them.
  • If the tree is loosely attached to the soil and moves freely by touching (weak or not properly formed root system).
  • When branches are weak, wilted, and droopy.
  • No roots should come out of the soil from the top (roots coming out from drainage holes means your Bonsai needs repotting and some root pruning).
  • You can see swollen bark.

If your already bought Bonsai tree is suffering from these problems, seek expert advice and appropriate treatment. The first thing to do if you believe your Bonsai is not healthy is to try revitalizing it. To do it, prepare a new slightly bigger pot, check roots and prune any rotting, brown roots. If you see any pests, use insecticides to get rid of them. Repot the tree and place it in a shade until it starts growing some roots. Don’t move it at all – this might cause an adverse reaction.

What to Consider When Buying a Bonsai

What a Healthy Bonsai Looks Like - What to Look At

While buying a Bonsai tree, assess the tree from every angle. It is crucial to look at certain features such as nebari, taper and thickness, and trunk movement. Later, these factors are difficult to change and require a lot of time and effort.

Before you choose a tree, make sure to consider climatic conditions and the amount of time you can dedicate to your tree. Some species demand the least care while others need regular care throughout the year.

 Also, examine foliage and roots for the signs of pests and diseases. Avoid buying a tree with obvious wire scars.

Weak foliage: Choose a Bonsai tree with dense and compact foliage. Weak foliage may be a sign of a root problem.

Nebari: It is also known as root flare. It is an essential aspect of Bonsai that is achieved by constantly pruning the downward growing roots. It’s hard to develop a proper root system in Bonsai as they grow in small pots. Any roots coming out of the soil from the top are not good.

 If detailed work is not done on the roots to create nebari, they will exhibit the problems of:

  • Crossed Roots
  • Roots will circle the trunk
  • Aerial roots

It may take time to change the root growth pattern, however, you can solve this issue with time. But it’s better to select a tree that has a well-balanced surface root system.

Unnatural trunk growth: Avoid choosing trees that have thicker branches as compared to the main trunk. A trunk should be upright, thicker from the base, and slender from the top. A very straight trunk also looks unnatural.

Taper and thickness: In most Bonsai styles, branches are cut back to promote outward growth. It requires heavy pruning to achieve taper and thickness. As a result, unattractive scars become prominent on the branches. However, these scars can be concealed by applying deadwood features. But you should avoid buying a tree in which several branches are allowed to grow from a single node. It can be hard to correct.

How Can You Make and Keep Your Bonsai Tree Healthy?

How to Tell If a Bonsai Is Healthy

A healthy Bonsai develops its defense system to fight against diseases. But unsuitable growing conditions can damage the physical appearance and health of your tree. Therefore, learn the specific needs of your tree and care accordingly.

Watering: Regular watering is essential to keep your tree healthy. How much and when to water depends on the species, and changing weather conditions throughout the year (seasons). Correct watering is not as easy as you might think. Even the pro Bonsai artists can slow down the growth of their trees if they stick to a watering routine, rather than assess the needs at a specific point of time.

  • Use a watering can with a fine hose like this one. Preferably use rainwater or bottled water for Bonsai. If rainwater is not available, use tap water kept in the bucket for 24 hours. Tap water contains lime that can be harmful to calcifuge trees (trees not tolerating alkaline soil). Plus, lime in water causes crust deposits on exposed roots of plants. Avoid using chemically softened water as well.
  • Water from above the plant using fine hose, until it starts dripping from the drainage holes. Wait for a around 10-15 minutes, and then water again. Make sure not to overwater your tree.
  • Don’t rely on rain to fulfill the water requirements of your tree during the hot summer days. Due to small containers, soil in the pot dries fast. Also, smaller root balls can’t hold enough moisture for longer periods. Water once or even twice daily, in the early morning during the summer, or in the evening. However, never water continually throughout the day.
  • During winter, there is a lot of moisture in the air. So, there’s no need to water if the potting soil is damp. Occasionally, water the trees placed in a shelter. Continue regular watering from early spring to autumn.
  • Avoid watering during midday (in full sun). Otherwise, the water droplets will scorch the leaves in the sunlight.
  • Make sure that potting soil provides good drainage and that your container has drainage holes.

Light: Generally Bonsai are sun-loving plants except for a few species that can’t tolerate strong sunlight. It doesn’t mean these plants can survive without light. Each species need a certain amount of light to carry out photosynthesis. Mostly evergreens, such as pines and Junipers, can grow well in full sun. Most deciduous trees thrive in full sun in early summer. During hot summer days, they should be placed in partial shade.

Fertilizer: Feeding your tree with organic or inorganic fertilizer promotes growth, and is essential for healthy growth. Basically, plants need microelements such as Nitrogen (N), Phosphorus (P), Potassium (K), as well as several micro-nutrients. The N.P.K ratio mentioned on the package signifies the amount of these 3 main elements.

  • Nitrogen helps in leaf and shoot development
  • Potassium promotes flowering and fruit development
  • Phosphorus is responsible for the development and proper functioning of roots. Plus, it develops disease resistance in plants.

Organic fertilizer promotes soil quality by adding humus to it. These fertilizers slowly release nutrients by reacting with microbes in the soil. You can apply organic fertilizer either by mixing with potting mix or spread small granules 2 inches apart on the surface. You can use plastic mesh covers to save the pellets from birds. Organic fertilizer is often a better choice than a synthetic one, because it helps develop good microorganisms in the soil. This will benefit a Bonsai tree.

Synthetic fertilizers are immediately available for the roots. They are water-soluble, therefore, don’t need microbial action for nutrient release. Apply synthetic fertilizers right after watering. Rather than applying in full strength, use a weak dose at a time. Avoid overfeeding.

The feeding requirements of Bonsai plants differ greatly. Avoid using fertilizer during dormant periods. Plants need more fertilizer during vigorous growth periods. In general, Bonsai need a fertilizer with equal parts of N, P, K.

Common Bonsai Diseases – How to tell if your Bonsai is healthy?

Is My Bonsai Healthy - How to Tell If a Bonsai Is Healthy - Tips

Just like other trees, Bonsai is also susceptible to pests and diseases. However, due to its smaller size, the removal of pests is easy as compared to larger trees. That’s why these trees enjoy a long life and good health compared to full-sized trees. The most common Bonsai diseases are mentioned below:

Rust: It is a fungal disease that can cause the death of foliage if left untreated. The symptoms include the appearance of yellow to orange colored bristles on the leaves. Rust mostly affects Junipers, European five Needle Pine, alder, birch, Scots pine.

Needle Cast: The Scots and European Pines are most vulnerable to this disease. The main symptoms are the appearance of little brown spots with thin black lines on the pine foliage. Normally, young needles of a pine tree are largely affected by this disease, rather than older ones. Sadly, it can defoliate an entire tree.

Grey Mold: The fungus attacks the new shoots and seedlings in deciduous and coniferous trees. Fungicides will be needed to treat this disease.

Oak Mildew: The oak mildew is fungal growth on the leaf surface. It produces white spots that cover the surface of the leaf, thereby blocking the light. Mildew can be caused by overwatering or under-watering. Fortunately, it can be treated by using fungicides.

Root rot: It is a fungal disease that affects the roots. It causes the browning and eventually, the death of roots. Waterlogging is the major cause of root rot. It can be treated by repotting plants into fresh soil. Make sure not to overwater your Bonsai tree.

Leaf spot disease: It is caused by fungus or bacteria. It leaves circular brown spots on the leaves. However, it doesn’t cause much harm to the trees. Remove the affected leaves and apply a fungicide.

Verticillium wilt: The fungus attacks the vascular tissues in branches that may result in the death of new shoots and branches. No chemicals are known to treat this fungus. Trident maples are mostly prone to this disease. The only solution is to disinfect the soil. 

Common Bonsai Pests

Bonsai Scale
Scale bug

Bonsai is also susceptible to pests that are responsible for damaging the physical appearance and overall health of your tree. Normally, three types of pests attack Bonsai: Borers, leaf-cutters, leaf and stem suckers. Here’s a list of the most common Bonsai pests.

There are natural insecticides that will help get rid of mites, mealybugs, whiteflies, aphids, thrips, powdery mildew and many more. These are insecticidal soaps like this (paralyze soft-bodied insects), neem oil, horticultural oil (mainly consisting of mineral oil).

Aphids: These are small insects that vary in shape and size. They are sap suckers and leave tiny yellow spots on the foliage. They affect the underside of the leaf more than the upper surface. Use soapy water to flush them or remove them by hand.

Caterpillars: These are small leaf-eating worms that can be easily spotted. These are most active during the summer months. Pick them from a leaf by hand and use soapy water to remove their infestations.

Scale Insects and Mealybugs: Scale insects have a hard yellow shell. They can easily hide in tight places along the stem, rapidly increase in number and suck the juices out of plants. Mealybugs have a waxy white coating. Spray insecticides to get rid of them. Natural insecticides include organic insecticidal soap, neem oil, horticultural oil.

How to Protect Your Bonsai From Pest Infestation?

How to Tell If a Bonsai Is Healthy - Post

A healthy Bonsai needs good care to stay away from pests and diseases. Pests contribute a lot to weakening of your plant’s growth. That’s why follow the below-mentioned key points to avoid pest infestations:

  • Avoid waterlogging, especially during the winter season.
  • Use a sterile potting mix.
  • Don’t move your Bonsai around after repotting. Put it in a shade until new roots develop. Even some movement can cause it to drop leaves.
  • Balance the pH of soil. Soil that’s too acidic and too alkaline soil invites pests and diseases.
  • Don’t place your plants in a shady location for longer periods.
  • The addition of humus to the soil acts as a natural deterrent to pests.
  • Don’t fertilize Bonsai for a month after repotting.
  • Always do the wiring before you repot your Bonsai. Otherwise, it will lose stability and root issues.
  • Remove debris, such as fallen leaves, from the soil surface.
  • Seal the pruning wounds with a sealant.
  • Don’t leave your plants in full sun with minimum water supply.
  • Repot your Bonsai when it’s root-bound (roots circled around a rootball and coming out of the holes).

Final Words

Hopefully, now you can easily spot if something is wrong with your Bonsai tree. Caring for Bonsai is similar to caring for a child. You have to love it, give it proper time and love. As a result, your tree will be happy, healthy, and strong.

Thank you for reading this post on determining if your Bonsai is healthy. To discover more posts on Bonsai care, please see this page.