AusBonsai

Hi everyone,

In addition to my Trident Maple having a bit of a rough time at the moment, my Japanese Maple is also not looking great. Both trees came from interstate and were sent to me via Australia Post a couple of months ago, unfortunately both trees haven't really bounced back from their journey. After getting some advice about the Trident on this forum, I applied the same principles to this tree. In other words lots of water, moved it to a position in my yard where it get's more shade and less wind, gave it a good dunk in Seasol for a couple of hours and have since fed it seasol once a week, and finally fertilized it last weekend. While my Trident Maple has started to look a little better (still far from 100%), this tree is still struggling. In addition to it looking very dry and generally pretty unhealthy, it has also developed a white spots in a lot of the leaves. Does anyone have any ideas on what is causing this? Or any more tips on what I need to be doing to bring it back to full health?

Thanks in advance,

Josh

Hi Josh,
To me it looks a little like wind burn and heat stress. How long did take to get to you from interstate? I'd wait a little longer, the leaves will start to drop and a new crop in spring. The white spots might be a worry, if the trunk and main branches are reasonably healthily you could try a partial defoliate. Take the leaves to a nursery they could help.
Cheers Rod

Thanks Rod, I will try a partial defoliate and be a bit more patient with with it. The white spots are a bit of a worry I must admit.

I think it was only in transit a couple of days.

Josh,

You're buying some good stock there mate. I second burn of some kind in the diagnosis of the spots.

I actually find this species very difficult in the Sydney climate. Much more difficult here than Tridents which do pretty well. Japanese Maples seem to grow well here in Spring and then get hammered in Summer from the sun. Shadecloth protection in summer is an essential I think.

The good news is an occasional leaf burn is very unlikely to kill your tree. Just a way of letting nature do its own defoliation

All the best, you seem to have some really nice trunks there.

Is it worth defoliating this late? It's going to lose its leaves naturally anyway, and if it's not in the best health leaving the leaves on will only help it. Isn't it a "rule" only to defoliate trees in good health?
If it is sunburn-apart from not looking great it doesn't cause any harm. Take one or two leaves in a zip lock bag to your nursery re the white spots, give it a foliage spray with seasol and see how it goes.
I think the white spots could also be from the burn/scorch-see link. Or powdery mildew but better pics and details (can it be rubbed off) of the white spots would be needed
http://www.missouribotanicalgarden.org/ ... corch.aspx

Is it worth defoliating this late? It's going to lose its leaves naturally anyway, and if it's not in the best health leaving the leaves on will only help it. Isn't it a "rule" only to defoliate trees in good health?

Agree. Hold off and see what next Spring brings this tree.

Okay thanks everyone, I'll hold of on the defoliate and see how the tree is going in Spring.

Cheers, Josh

Hi Josh,

Just check there is nothing suspicious on the under side of the leaves, as that's usually where any nasties live.

You seem to have plenty of new growth coming through, so you could just remove some of the larger damaged leaves to let a bit more light/air to the newer foliage.

As we have a small growth period now with the trees the idea of a ' partial' defoliate is to see if the trees will bounce back in the spring. Normally you would wait , I agree, but if your a little concerned you tend to try something. If it's not on top the problem could be underneath ; drainage , grubs, rotting roots , soggy soil, not enough fert ( if the tree is unhealthy fert is a no no. ) you could give a very weak Seasol tonic to help it along and build some resistance for winter. The problems are endless and scarey but I feel sure it's burn from heat and sun also adapting to new climate.
Cheers Rod

Hi All
For what it's worth I am in Adelaide living on the plains & I have given up on Maples as the summer heat eg 46 Deg, under shade cloth still manages to end their days.
In relation to the white spots maybe try mixing up plain soap into a thick solution & apply it with a soft cloth. I have had success in removing white spot from other plants using this.
Rod

rdc wrote:Hi All
For what it's worth I am in Adelaide living on the plains & I have given up on Maples as the summer heat eg 46 Deg, under shade cloth still manages to end their days.
In relation to the white spots maybe try mixing up plain soap into a thick solution & apply it with a soft cloth. I have had success in removing white spot from other plants using this.
Rod

How do tridents go over there? No good too? I'm in a cool part of Sydney in summer (near the water) and I find while Japanese Maples get destroyed, Tridents do pretty well with the odd leaf burnt on very hot days.

Hi Josh

I have very similar problems with my Maples. After trying everything i almost gave up. Then someone said to me, what water do you use. I was using spring water, all my trees were fine except for my Maples. I found that there was to much salt in the water and this was effecting the maples.
So my question is are you using borehole or spring water? If so this could be your problem???

Switch back to Municipal water and see the change.

Brett

Thanks everyone, I really appreciate all of the advice.

Increasingly I am thinking the white spots are just sunburn, since moving the tree and giving it more cover it does seem to be doing a little better. I can't find any evidence of any bugs or anything else that might be causing it. Anyway the spots don't seem to be spreading to other areas of the tree so that's something at least.

In terms of water I give all my bonsai straight tap water.

In my very limited bonsai experience I think the main reason why this tree has been struggling of late comes down to climate. Sydney has had a very hot dry summer (apparently it's driest summer in 27 years) and despite my best efforts all of my Japanese Maples have struggled. I purchased three relatively small Japanese Maple starters from Bonsai South about 6 months ago, all of which were very much quality, healthy trees. Unfortunately 1 has died and the other two look like they could go either way.

Anyway I'll post pic soon of this Maple when hopefully it is looking a lot healthier.

Josh