Hi I have a Japanese Maple which has a white sticky mould like material growing at the base of the bark. It doesn't appear in the soil. The tree is planted in a large container pot. It's a few years old and has just recently got new leaves. The weather has been very wet recently and the tree was in mostly a shaded/partially shaded area. I repotted last year but I didn't use organic soil as it would appear is a requirement. I moved it in to a sunnier position yesterday as I thought the soil may be too wet causing the mould to grow. A small number of leaves are also going brown at the tip and curling up. Any ideas or suggestions would be appreciated. Thanks Marian
You do not need to use "organic soil" to grow maples. One requirement is that it must drain well. It seems that I have seen white mold growing in rather damp mixtures in which bareroot roses are packed, but it is harmless. I hope that moving the tree into a bit more sun solved the problem, otherwise it may be a bit too moist, which I have read in here in the forum can cause leaves to brown, just as if the plant were thirsty.
Yes, it probably rains a lot in Dublin. In that case, you need a mix that drains well - look around on the forum for suggestions in earlier threads (use of pine bark pieces, etc). I'm not sure what you mean by 'organic' mix, but people use anything from pine bark to certain types of inorganic material (grit, lava rocks, etc) with good results. If your tree is only 'a few' years old, and you put it in a large container, you have higher moisture as well in the mix, the roots are getting too wet. (Unless you mean it's a big tree that has been in the pot for a few years?) If this is the case, I'd use a smaller pot when you repot (and you can put that inside the larger one, if it's a question of how you want it to look - and then pot up over the coming years). If the pot is too big, you might want to repot in the fall, not next spring, since it will get even wetter in the winter, which can also lead to other diseases. I have maples in smaller plastic containers placed inside larger containers, for instance, the whole affair covered in mulch. Looks fine.
