I’ve had this field maple (acer campestre) for a year. It did something like this last year in August. It’s been like this for about a month. At first it was just a few leaves and the advice I got was to not worry and sometimes that happens. Now it’s spread to almost every leaf.
What could be the causes? How can I help this tree?
What is your soil and root condition? Could the roots be too wet?
I find them to be very strong and in need to repotting every 2-3 years. I grow in a fairly free draining mix so I get good water/oxygen exchange.
Might it be a lack of magnesium?
Might be lack of magnesium. I only use Miracle Gro, and that does not have magnesium in it. I’ll add some magnesium to the water next watering.
The soil is not very good. I couldn’t repot because this same thing happened around august and I wasn’t sure it could take a repot this spring. It’s not pot bound though, it’s in a larger pot than when it came, but I had to just slip pot out of necessity (came with no pot).
Could it also be fertilizer burn? The use of Miricle Grow in a not that good soil could lead to salt build up. You might want to flush the soil really well when watering and switch to an organic fertilizer.
Might be, I’ll try flushing the soil out.
Looks like sunburn. Move to shade and maintain balance of water and oxygen in roots.
I’d go with sunburn.
I have some palmatum that do the same thing every year when temps go up.
Put it in shade or under a shade cloth maybe go easier on fertilizer.
Check the leafs in the interior, if those are ok, it’s most likely sunburn.
Sunburn was my first reaction.
My field maples spend several hours per day in full sun, including some which are primarily midday and afternoon sun, and I rarely see any signs of sunburn. They have a tough leaf if acclimatized and given primarily organic feed. I am a little further north (48.6 degrees) but at the transition from grasslands to pine forest at 2000 ft. so the sun can be fairly intense.
I’m going to weigh in with it being an overwatering and wet roots problem. I’m in zone 9 in N. California and my field maple is in full sun for most of the day. No shade cloth. I don’t have this problem on my field maple but I’ve had the browning of the leaf tips problem on other trees; trident maple, linden, olive, valley oaks and others. My “fix” has been to keep the trees in sun and monitor the soil moisture and watering carefully. Using a drier mix next time I repot should help too.
I ended up giving it an emergency repot. The soil was awful and it had a very large area below the trunk where the shin should be, which was just organic soil with not a single root.
I’m keeping it in a black bag for now (like you would a yamadori) and it’s pushing new growth.