Why Black Spots on Bonsai Leaves?

Black Spots on bonsai leaves are always an alarm signal and a warning that the plant is sick. You may notice that the sheet is darkening uniformly and progressively, or you may detect the appearance of black spots or certain areas that are blackening. In any case, it is important to find out the causes of plant leaf spots in order to prevent the spread of a possible disease.

In this article we tell you why black spots on bonsai leaves appear . Discover the most frequent causes and the best tips to learn how to remove black spots from bonsai leaves. Keep them in mind especially now that summer is over and it’s time to prepare the garden for the foreseeable drop in temperatures.

Why Black Spots on Bonsai Leaves?

If you are a bonsai gardener ,you have most of the times observed black Spots on bonsai leaves. It has numerous reasons those are described below-

Lack of Irrigation

Especially when the tips of the leaves of the plants turn black, the first question to ask yourself is this: have I watered them enough? Plants are living beings, and, even if we know it, sometimes we can forget their basic water needs, especially during vacation times when we can pay less attention to them.

If you haven’t watered your plant enough, this may be the answer to why plants get black leaves. Dark spots on the leaves indicate that the plant is drying out and you should resume proper watering immediately.

Read More :How To Water a Bonsai tree indoor Ultimate Indoor Bonsai Watering Solution

Lack of Proper Location bonsai leaves burnt

It is important to remember that each plant requires a specific location, both inside the home and outside. Some do not support direct exposure to the sun. If you detect Black spots on bonsai leaves, confirm that they are in the right place considering their sun or shade needs. The problem may be that the sun is causing them burns that must be avoided. Also, if you have a plant exposed to the sun, be sure to water by pouring the water on the ground and not on its leaves to avoid further damage from the sun’s rays on them. Finally, always water first thing in the day or late in the afternoon, never in the central hours.

Fungi and Bacteria

Image Credit : mundodeportivo.com

Without a doubt, the presence of fungi on plants is the most common cause of black spots on bonsai leaves. These can appear at the tips, at the edges, or scattered in the form of points throughout its surface.

Downy mildew, powdery mildew or sooty fungus (sooty mold) are some of the fungi that can most frequently infect outdoor plants and shrubs. It is very important to remove the affected leaves and treat the plant as soon as possible.

Take a look at this other article on Home remedies for powdery mildew on plants, which are also used to treat mildew.


Aphids, caterpillars, red spider mites or whiteflies are some of the insects whose excessive presence as pests can contribute to the appearance of Black spots on bonsai leaves . Actually, on many occasions, fungi and parasites go hand in hand, so the fungus is the cause of the black color. Both form a dangerous tandem that can endanger the health of the plant. If the cause of the black leaves on your plants is a pest.


Warm temperatures, high environmental humidity and poor ventilation.These 3 elements collectively are the right breeding floor for fungi, micro organism and pests to emerge that make the plant sick, inflicting black spots on bonsai leaves because the first symptom. In indoor plants it usually happens, for example, during vacation periods, when the house is closed (without ventilating) for several days. The problem can also arise in outdoor plants if they have been located in a too small and variegated flower bed that does not allow air to circulate between them.

Unsuitable soil

When there is no obvious cause that explains the black spots on bonsai leaves, the reason may be in the very substrate that sustains and feeds them. The alkalinity or acidity of the soil influences its growth.To forestall the arrival of those spots it could be essential to accurate the pH of the soil.

You must additionally test that there’s no detail this is affecting the roots, stopping the regular improvement of the plant. A stony layer, an underground pipe, etc.It may be the motive why the water and vitamins it wishes aren’t accomplishing the plant. As a consequence, black spots appear because it has begun to dry. Again, a change of location could do the trick.

Read More :5 Best Types of Bonsai Soil For The Bonsai Gardener

Excess manures and fertilizers

Regularly fertilizing flowers, trees and shrubs is a necessary measure for them to grow healthy and carry out the flowering process. However, an excess of fertilizers can be counterproductive and ‘burn’ the leaves of the plants from the inside. If you detect black spots, check that you use the right fertilizer for your plants and that you do it in the right amounts.

Read More : The Ultimate Guide To Best Bonsai Tree Fertilizers

How to treat black spots on bonsai leaves?

Adopting preventive measures that save you your plant life from getting ill is usually the satisfactory option. In order for them to grow healthy and beautiful, you must put them in the right place, water and fertilize them with due frequency and monitor ventilation. If, even so, you detect black spots on the leaves of your plants, you must act immediately because their presence does not bode well.

To try to recover the health of your plant, some tips that should be taken into account are:

  • Fungicides are essential if black spots on plant leaves are caused by fungi or bacteria. Apply them by spraying on the entire plant and especially affecting the most affected areas. Remember that you can make homemade fungicides based on baking soda or vinegar diluted in water.
  • If the spot occupies a large area, it is preferable to remove the affected leaf to prevent the infection from spreading throughout the plant or to nearby plants.If the motive of the stain is that the sheet is dry or burned, the satisfactory alternative is to take away it as well.
  • Do not forget to remove the fallen leaves in the soil of the pot or garden to avoid the spread of the disease. Similarly, preserve the equipment you operate withinside the bonsai garden clean.
  • Now that you know why plants get black leaves and if you want to continue learning, we recommend this other article on yellow leaves on plants: what they mean and solutions.

If you want to read more articles similar to Why do black spots on bonsai leaves, we recommend that you enter our Gardening and plants category.

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