Hi,

I’ve had this cherry pre bonsai for several months, and since a few months the leaves have started to get lighter.

It gets a lot of direct sunlight every day (might be the issue?), I water it semi daily dependent on the weather, and I’ve given it a good amount of Biogold fertilizer

Any ideas?

Is it inside? If it is then that is the problem. Lack of light humidity etc.

No it’s outside, hardiness zone 8b

I think it is somewhat fun to hear people have had the tree for several weeks or months and they have been good up until now. Trees slowly reacting to the changes in care and environment, so it is what is to be expected. However to create a bonsai you need to keep the tree healthy for years and decades, not weeks or months.

People that has been around for years, that has something to chip in on a bonsai forum about cultivation and styling does not have much experience with bad health issues and are not really experts on it. Some repotting stress, some bugs, but that is it. And everything is handled long before it is a severe health issues. Because that is what it takes to be successfull in this hobby.

You may get better answers in a gardening or crop farming forum.

But I did google it as I remember something from an old book. The term I remember was intervienal chlorosis. There are many different reasons for this to happen, but there are one that I think fits your situation best. Iron deficiency. Many acid loving plants get really big problem with Iron uptake when PH is too high. Since cherry is an acid loving species and it takes quite a while to increase ph in soil i think it fits. So my guess is that you have very hard tap water and that the soil has increased ph slowly from that since you got it. But just to be sure, try to find out what your tap water are like. The important parameters is PH, KH and to a certain extend GH. Kh is sometimes called alkalinity and measured in mg/l/PPM. GH is short for general hardness, but sometimes it is called total hardness.

Come back with data on your tap water to see if my guess is correct. You may get the figures from your water plant or you can measure it yourself with simple aquarium testa.

Yes, I have had several bonsai trees for years, but I was trying to give context to the situation of my tree. I don’t understand why it’s necessary to respond so condescendingly. This is a species that is used for bonsai cultivation and I expect people with bonsai experience to have experience with this tree. If you don’t then that’s fine, no need to be insufferable about it.

90% of the water has been rain water so no that’s not it.

I am sorry to have upsetted you, that was not my intention.

Yes there are many people here that have experience with this species. Not that many that have experience with healt issues and even less that have experience with this odd phenomena. Proboably none?

I am still  almost 100% sure this is intervenial clorosis. The symptoms fit perfectly. Not that sure that it comes from Iron deficiency anymore. However, adding some micro nutrition supplement will rule out Iron deficiency as well as a few other possible reasons. Damaged leafs will not be repaired and you may not see any improvements this year. But it is always better to rule out the most likelly reasons before jumping to other solutions. Come spring flush you will know and can look into other possible reasons and solutions.