I posted last year about my English elm leaves turning yellow and eventually dropping from end June to August. This year the lower branches are showing dark spots and some leaves are also tuning pale and some have dropped but otherwise the tree is vigorous and has pushed out lots of new growth. I try to only water when the soil is dry 1/4 inch below surface but still wonder if I still water too much. The soil seems fairly compact. I have treated once last week with a weak copper fungicide. I am wondering if I need to do anything else now other than only water when essential? Should I do a repot in case the soil is too compacted? When I purchased last year I was told it had been repotted 2 years prior. Thanks in advance for any thoughts and advice
How do the interior branches look? The canopy is so dense I wonder if part of the problem could be that lower branches are just shaded out and weaker. If the tree withdraws resources from à less viable branch (from à photosynthetic point of view) it would be more susceptible to things like spotting that a vigorous branch would fight off.
Do the leaves that have yellowed and dropped simply get yellow and drop or do they get riddled with black spots first?
if the tree was repotted two years ago, did it go from à really big spot into this pot? Was the canopy reduced proportionally with the root reduction? The tree looks really healthy now otherwise so I doubt it’s shedding to stabilize its proportional amount of roots. It really doesn’t look Ike it’s shedding that much.
Before doing a whole repot, still a drastic operation, but you could slip the tree out of the pot and test the roots for fungus just by seeing if the sheath sloughs off of them, if there’s a weird smell, or if they are nice and light and healthy. I wouldn’t recommend this based on the photos tho. It’s too invasice and you can stand to be patient.
Thank you for the comprehensive response. Yes, I agree with you that it is too soon to panic and do an emergency repot just now. It is just two lower branches that are looking weaker with yellowing leaves and eventually black patches and curling at the edges. I did a fair bit on f thinning last weekend and moved to a slightly sunnier spot (morning sun) so will see if the branches perk up. I’ll also keep a close eye on my watering.
Google ‘Dutch Elm Disease’…
K
thinning may be the answer. looks very dense. the black spots could be Cladosporium or Alternaria if the leaves get water condensed out on them especially in the dark. elm get that pretty easily. thing about fungicides is I don’t think they last a long time and they need it before the fungus appears. check to see if soil is root bound. maybe clean up the surface and put in some fresh soil if not draining as well as you would like. what is the soil type? is it one you work with normally? you may be fretting too much. tree looks healthy from the pictures. everyone is giving you good information in my view. Dutch elm disease? I have never seen it in bonsai and it flashed through my area already. what is left elm-wise seems resistant. don’t know english elm, we have american elm, siberian elm, and chinese elm here.
Thank you. I bought it last year and it’s in an akadama mix but the soil is very compacted. It is definitely getting weaker despite pushing out a very vigorous first flush. I am thinking of slip potting into a larger container with fresh soil to allow me to inspect the roots and also undertake a light aeration of the root ball with a chopstick. Thanks again for the advice
I also believe it may be to do with the density of the foliage, leading to those dense areas not receiving enough light, and notably, having very little air circulate there. Not to say that is the reason, but poor airflow can create conditions where certain fungal problems are more likely. All that said, the tree is looking pretty healthy.
I have a field elm that I also just today pruned back a bit to allow more airflow and light into the inner areas. Here you can see the before, and after (I think I will do a little more pruning to provide even more room).
