I have an Euonymus Europaeus that is worrying me. I bought the tree last autumn and repotted it this spring into Akadama / Pumice. The roots were healthy but I reduced them a bit to fit it into a smaller pot. After repotting the first flush was healthy and very vigorous so I cut it back after the first flush hardened off in May. Since then the buds on the tree didn’t leaf out anymore, it just stayed as it was.
On top of that I began seeing signs of pests in the last to month that I couldn’t really identify. First I thought it was spider mites but now I think it’s either soft skin mites or thrips. I’m not sure though. Can you help me identifying these? Also, what should I treat the tree with? I do have a pesticide that’s specifically against spider mites (Kanemite SC, based on Aceqinocyl) but since I’m not sure I would rather go with Neem Oil.
My guess is that the two problems are related, i.e. the tree doesn’t leaf out because of the pests. My worry is that the tree could be weakened to a point where it could die or not leaf out anymore next spring.
For some context: The tree is located in Berlin, Germany and is standing on a south facing roofed balcony in semi shade. The microclimate there is rather dry and hot.
I can’t offer any insight into which insect you have and how to treat. However, I believe that the combination of repotting and cutback left the tree weak and subject to the insect attack. The tree needed all of the new leaves in order to regrow the root system. With that thought, you might try washing the insects off with a hard stream of water every few days as the least stressful approach to treatment since even the most benign insecticides are often slightly phytotoxic.
I agree with Marty. Looks like spider mites but you are doing too much to fast. This is not a refined bonsai. insects and disease are a sign of unhealth in the tree. treat it for the spider mites to get them under control. if not sure on spider mites - use a broader spectrum insecticide. pot it up so the roots have more room. you could do that without disturbing the roots at this point and just giving it a bigger pot - Japanese grow pots are my go to for tree development. then stop cutting it back until it recovers and you figure out where you want to go with it for development. development phase is generally not a “refined” bonsai look. it won’t look great while you are developing it. do you work with any knowledgeable professionals or have a club you can attend? you need bonsai buddies to bounce ideas off of. looks like you can pick good material. you just need more help in the bonsai development.
One insight I can contribute to euonymus may or may not apply. I have euonymus alatus and I only get one flush per year. When I prune post flush harden it sets buds for the following year and that’s it. And watch those buds over the winter, critters like to eat them.
I think I learned my lesson and will go easier on the tree in the future. I decided to wash the tree with water and spray it with a light application of Neem oil afterwards (as Neem is not specific to arachnids or insects like other chemicals and also relatively harmless to most plants) and repeat this a few times.
@Tiibee Thanks for sharing your experience with Euonymus. The two species are very similar so it could be just normal that I don’t get a second flush. It is surprising though as I don’t know of many decidous species that don’t get a second flush. Interesting!
