Brown spots on chinese elms

[Nos72]

Hi people,

i have a few elms and recently noticed the leaves get a yellow spot on them which eventually goes brown and kills the whole leaf. i actually lost a whole starter bonsia with this happening. any ideas on why or what and how to treat or prevent would be great.

pics will be added soon.

thanks,

[Nos72]

thanks everyone... your soooo helpful....

[craigw60]

Hi Nos,
I reckon the spots on your elms are caused by over watering. Chinese elms come from a dry climate zone and hate being too wet. I will be interested to hear what others have to say as this seems to be a recurring problem.
Craig

[Jarrod]

Yeah I would agree. Looks like your soil holds to much water.

What do you use in you soil?

[Nos72]

that would sound about right i spent some time away and had an auto watering system on recently, im just using a premium potting mix for soil. i will let them dry out a bit more inbetween watering, and check that they drain ok.
thanks for your replys

[craigw60]

Hi Nos,
auto watering and bonsai just don't mix. Each tree species have different watering requirements so to blanket water will always cause problems. I have not had a summer holiday for 25yrs I always go away in jul aug when watering is a non issue. Also you may want to review your potting mix and get a sieve to take the dust off your mix it tends to wash down to the bottom of the pot and form a sludge. Just a couple of ideas.
Craig

[bodhidharma]

Hi Nos72, You are definitely waterlogged. It looks like a fairly standard Chinese pot and that would mean your holes are not big enough. First thing on most Chinese pots is to make the hole larger. Easy done with a diamond tipped hole saw and drill. If you are using good old standard potting mix you need to add some ingredients to make it more open. Try adding 3-5mm scoria some purlite and some organic material such as a good compost, pine bark etc. The main thing you are looking for is drainage. Elms also yellow when not fed enough. At this time of year it should be every 3 weeks or so. Dont rely on the fertilizer in the potting mix it is usually cheap and nasty. in the future you might want to consider mixing your own soils. There is a wealth of info on this site to help you out. Cheers

[NBPCA]

Also too much shade and not enough air movement.

Grant

[Leigh Taafe]

Also too much shade and not enough air movement.

I agree - elms thrive in full sun - they love it ! But if your tree has been growing in shade for some time - dont throw it into full sun all at once! Do it gradually - otherwise the foliage will burn.

Cheers,
Leigh.