Ever Red in a pot, root flare is exposed, soil is a mix of ericaceous, grit, bark and perlite. Quite free draining and what I’ve had success with elsewhere for years. The pot drains just fine, no problems there and it’s terracotta so porous. That said, the plant looks to me to be overwatered, but I’ve never had this before and wouldn’t mind confirmation. It’s watered in line with all my other Acers with several on moisture sensors / others using a manual moisture probe and so I’m a bit stumped as to how it’s happened. I’ve stopped any watering for now, it’s kept in a mainly shady spot but I’d welcome any advice on whether I should do anything else to try and resolve or diagnose the issue? Or, do I just relegate this to the shade corner and pray for next year? Other than this problem child and a Katsura struggling from last years weather, I’m pleased to report the rest are doing well. Thanks all.
It would be pretty hard/impossible to overwater in that soil mix, especially in a terracotta pot. Unless it sat in a puddle of water all winter, or something like that, causing anaerobic conditions in the soil. Root damage from vine weevil grubs in potted maples often presents as wilting at this time of year. (If you preventatively treat with nematodes ignore this bit). When this occurs the grubs have eaten all the small roots and root cambium on larger roots over winter. The tree leafs out with energy stored in the woody roots and trunk then stalls and fails as it runs out of stored nutrients and cannot make any more due to lack of feeder roots. Unpot the maple to check the condition of the roots and look for 1cm white grubs. The tree can usually be saved if you get to it quickly enough, but may take a year or two to get back to full health. Think of it as a very severe root prune! If you find grubs remove as much soil from the remaining roots as you can and repot in fresh media. Treat with nematodes to kill any grubs that might remain. If there are no root eating grubs then try and think if there is anything else in your situation that may have caused a negative impact to root health over the winter.
One other possibility could be aphids? If you had a heavy influx earlier in spring ? Aphids can really distort the spring growth and give that distorted look even if they have already moved on or been washed away by a heavy rain or eaten / attacked by other insects. Shaded area and not over watering until signs of good health returning is good
Thanks both for taking the time to reply and your advice. For context, this was a new purchase in late winter and so I’m unsure of how it stored or was overwintered. It may very well have been sat in wet conditions although the supplier is reputable and so I’d be surprised. It did get heavily attacked by aphids at the back end of April, so much so, you can see them still in places on the tree. I’m wondering now whether that could be it, they’ve never been that big an issue before. I tend to let nature run its course and hope the ladybirds do their thing. I’ve done an inspection of the roots today and can’t see any grubs. I’m hoping it may just be an aphid issue and patience will resolve the trees health. Fingers crossed me playing with the roots won’t do too much damage in the short term or make things worse.
‘stp’ unpot and can’t ses any grubs, so i think that negative impact to root health over the winter is PYTHIUM, (rot roots). You have to repot with a new substrat as said Maf. (In such a case, i use a narrow pot and pouzzolane).
