With their artistic growth and small size, bonsai are one of the most important aspects of Far Eastern, or more precisely Japanese, garden art. Due to their small growth habit, kept in equally small containers, they require a lot of care, whether it is an indoor or outdoor bonsai. If the plant loses yellow or even green leaves, there is usually a problem that you must take care of so that the artistic dwarf does not die completely.
causes and measures
dryness
Drought is a big problem for many bonsai as they have little substrate available. Depending on the bonsai species, the plant reacts to prolonged drought by losing green or yellow leaves. A lack of water is often the cause of leaf loss, especially in specimens in which the roots protrude from the bowl together with the substrate. The following solution is recommended here:
- if the substrate is solid, immerse the entire bowl
- leave in the immersion bath until no more air bubbles rise
- then drain well
- do this process once or twice a week
- in the summer every day, but less often in the winter
- do not dive in loose soil
- only spray the root ball with plenty of water
- spray until the water comes out of the drainage holes
- this operation must sometimes be carried out daily, except in winter
- water again as soon as the substrate has dried slightly
waterlogging
A bonsai, regardless of whether it is a ficus ginseng, pine or penny tree, loses its foliage in most cases when it becomes waterlogged. Too much moisture leads to lazy of the roots, which in turn causes the loss of green foliage. If your plant gets too much water, you must act immediately and repot freshly:
- carefully remove the plant from the pot
- loosen the soil from the roots with a delicate touch
- with disinfected or clean scissors, thoroughly cut off rotten roots;
- feel fresh substrate into the tray
- only use high-quality bonsai substrate for this
- place the plant in the fresh substrate
- then do not water for the next four days, then only water if necessary
The repot is the only way to protect your bonsai from waterlogging, as the roots rot quickly and can no longer regulate the distribution of nutrients. Yellow leaves are less likely to be a cause of waterlogging and are highly dependent on the tree species.
tip: it can happen that another leaf loss occurs after repotting, because some species are sensitive to root pruning. However, you usually don't have to worry about this as long as the dwarf has been given fresh substrate and dry roots.
light
Typical of the dwarfs is the high light requirement, since they are still real trees acts. The plant will lose foliage as soon as there is insufficient light, which is mainly reflected in the loss of a large amount on one side of the tree. This is usually the side facing the window, when the sun can shine with all its strength on the bonsai at midday or in the early afternoon. Yes, a bonsai tree needs a lot of light, but no direct sunlight at the warmest time of the day. The plant burns, so to speak, in the sun. The following measures will help:
- change the location so that it is not in the direct sun
- alternatively, hang a curtain or sunshade
- the dwarfs only need a few hours of pure sunlight in the evening or morning
If the bonsai loses pale green and yellow leaves, it is too dark. In this case, he drives so-called light shoots that are looking for more light, which will significantly weaken the plant over time. Only one helps here relocation with more light. In addition, you must cut off the light shoots directly on the trunk so that they no longer steal energy from the bonsai tree.
Incorrect humidity in winter
Do you store your bonsai over the winter over the heater? Dry heating air and low humidity are a major problem for the crop and leaf loss is just one of the consequences of the constant heating of the root ball and substrate. Here it is no longer enough to water the plant sufficiently, but only one relocation. Choose a cooler room, such as a bedroom or guest room, with windows that face east or west. In this way, the tree receives enough light and heat, but does not suffer from dry heat. Don't forget to spray and water, of course.
tip: if the leaf loss is already well advanced, you can pack the plant in a transparent plastic bag, as this will regulate the humidity quickly and effectively. This method is not limited to the winter and you can use it all year round to protect the sapling from stress.
Wrong substrate
Many bonsai beginners, in most cases, do not change the substrate in which the plant is after purchase. However, in many cases this is wrong, very clayey soil, which is not suitable for the crops and leads to leaf loss or other problems. Repotting in fresh bonsai soil is the only solution here.
Wrong pot size
The following applies to bonsai: the roots need space according to the size of the crown. That is, the larger the crown, the larger the shell must be. If your bonsai looks healthy but is losing foliage, you should carefully lift the plant out of the pot and check the roots. If fine roots are visible on the outside of the substrate, you need a larger bowl. Get a new pot that offers enough space and repot the plant.
over-fertilization
Over-fertilization can happen quickly due to the pot size and will result in yellow leaves plaguing the plant, and they may also fall off. The reason for this is an excessively high content of salts that accumulate in the soil. Species such as Ficus Ginseng in particular first develop yellow foliage before they lose it. Solve the problem as follows:
- if the substrate is solid, immerse the bucket in water
- this allows the fertilizer to spread better and excess fertilizer is flushed out
- if the substrate is loose, you must definitely repot
- also if the bonsai has already lost a lot of leaves, which indicates massive over-fertilization
- before pouring in fresh soil, be sure to clean the tray
- thereby avoiding possible accumulations of fertiliser
- then place the plant in the fresh substrate and do not fertilize immediately
relocation
If your bonsai suddenly loses green leaves, this can very well be related to a change of location. Since the plants are a special form of husbandry, they are very sensitive to a change of location, even if it is not ideal for them. The change can stress the plant, especially in the first few days, so you should give the plant some time in a new location if it suddenly loses its leaves. In most cases, the sapling will recover as long as you don't immediately decide on a different location. The less the plant moves, the better.
draft
Drafts usually do not harm bonsai outdoors. However, specimens should not be exposed to drafts in your living space, especially not in winter. This can create a heat imbalance and lead to shedding of green foliage. So make sure you choose a suitable location without subjecting the plant to additional stress, as described above under the change of location.
No problem: seasonal leaf loss
There is another form of leaf loss where yellow, green and even red leaves fall off the bonsai. Many people forget that bonsai trees are really small trees. For this reason, the natural course of the year leads to a loss of leaves, as is the case with deciduous trees and some conifers. While a Ficus Ginseng should not lose its leaves, fall leaf loss is predetermined for a majority of deciduous trees within the temperate zone, such as the elm (bot. Ulmus). However, the following conifers can also suffer leaf loss:
- Primeval Sequoia (bot. Metasequoia)
- Larches (bot. Larix)
- Golden larches (bot. pseudolaris)
Compared to the conifers mentioned above, there are other trees that only lose their needles after two to three years:
- White pine (bot. Pinus strobus)
- Scots pine (bot. Pinus sylvestris)
- Spruces (bot. Picea)
A black pine (bot. Pinus nigra), on the other hand, only loses its needles after three to eight years. Be sure to find out what tree species your bonsai is. This is the only way to be sure that the leaf loss is seasonal and not due to one of the causes mentioned above. For example, if you grow an evergreen juniper as a bonsai in the garden and its green needles fall off, then there is a bigger problem behind it. Also, be aware that deciduous bonsai really lose their foliage in the fall.