New Japanese Maple "Sharp's Pygmy" leaves are browning

[arctic107]

I just acquired a new Sharp's Pygmy Japanese maple. It arrived from Mississippi yesterday afternoon. I looked at the Japanese maple this morning and again about 30 minutes ago and noticed that the leaves are browning.

I watered the tree yesterday afternoon after putting it in my enclosure, again this morning, and again 30 minutes ago (since the temperatures are in the high 90's). I also have a 40% shade cloth on the ceiling of my enclosure.

Is the browning just because of the stress of moving and acclimating to the new environment?

Thanks!

 

[BrightsideB]

It could easily be the heat from shipping the tree with this eastern heat over the past week or so. Make sure the soil can absorb water and hold it for the roots. Soil can become hydrophobic if it dried out. And watering will not hydrate all the soil.

I’ve had certain Japanese maples dry out in too much heat and the leaves look like yours. If you can give it morning sun and shade during the hot times of the day it’ll help. Shade cloth is good.

Also upload some more photos of the pot and soil it’s in. Also a small scratch of the bark can confirm more serious dieback. If it’s green then the tree is still alive pulling water up the trunk. But that isn’t always the case if it is in the middle of dying. It can still be green but not as hydrated or a more dry dull green if dying or not enough moisture being pulled up from the roots.

Sometimes they can lose leaves due to heat or drought stress and then push out more new foliage. If this happens it’s still alive.

Ordering trees to be shipped during hot or freezing months can be a gamble.

Hope your tree is just stressed from the transit and survives.

 

[BrightsideB]

I looked at the leaves better. Usually heat or not enough water will dry out the tips first due to inadequate transpiration to cope with the heat. Yours are drying from the inside out which shows a hault of transpiration into the leaf. It could be a mechanism to just shed the foliage. Also death can show up this way. Little scratch of the branch can help confirm. But keep it out of direct sun and make sure the root ball isn’t dry.

 

[arctic107]

Thanks, BrightsideB! Yes, the browning is going from the inside out and not from the leaf tips inside. That is a good call out. I've uploaded 2 pictures of the bonsai that I took about 24 hours ago. For perspective, the left is South.

 

[BrightsideB]

Wow very nice start! It looks rather healthy. I think that the apex could either be shedding leaves or there may be some dieback. It starts at the apex and the end of branches. That seems to be where the leaves are shedding primarily. I’d worry if it continues to lose more leaves that look healthy currently.

 

[arctic107]

Thank you! It's an absolutely beautiful tree and I can't wait to work with it. I'll keep my eye out for continued browning.

 

[WNC Bonsai]

Thank you! It's an absolutely beautiful tree and I can't wait to work with it. I'll keep my eye out for continued browning.

Check out Peter Chan’s YouTube (Heron’s) video released today on dealing with scorched JMAP leaves. Also just as a tip, I never order trees in the summer, much less during a heat wave, you are just asking for this to happen.

 

[arctic107]

I happened to watch that this morning! Given how well the tree looked yesterday, I didn't think I'd need to do it to my tree (especially so soon)!

 

[Shibui]

Brown tips and edges is usually dehydration
Entire brown leaf is more often sunburn in my experience. It appears the brown leaves are all on the outside and mostly toward the top and one side of the tree?
Sunburn is usually when leaves that are adapted to shade are suddenly exposed to stronger sun. Leaves can adapt to changes in sun but it takes a few weeks of slowly increasing sun intensity/time to allow them to make the changes.
good news is that JM usually recover. Just snip off the affected leaves. New buds should emerge after a few weeks to give a fresh crop of leaves. New leaves that open in your environment will be better adapted to the prevailing light conditions.

 

[arctic107]

Yes, the brown leaves are all on the outside of the tree. Thanks, I'll give this a shot!

 

[arctic107]

The leaves are also brown and NOT crispy.

 

[Piedmont Bonsai]

Assuming this came from brussels bonsai, this issue is almost entirely due to the soil they use. It stays too wet and you need a good wet/dry cycle in your soil for water to adequately transfer through the tree.
Soil that stays too wet in combination with the brutal temperatures we have had recently in the eastern part of the country is a recipe for disaster with japanese maples.

Shade and closely watching the moisture in the soil is your best bet here. Next spring you definitely want to do a good repot. Bare root and change out soil to good bonsai soil.

 

[arctic107]

This indeed came from Brussel's! I'll strongly consider repotting with new soil next Spring. I moved the bonsai to underneath the shade of my non-bonsai Japanese Maple. I'm thankful that the tree's leaves don't look awful!

 

[arctic107]

I've discovered that there is a whole layer of perfect, green leaves underneath the burnt ones!

 

[Shibui]

I've discovered that there is a whole layer of perfect, green leaves underneath the burnt ones!

This is another indication that the outer leaves are sun burnt. The inner leaves were protected from direct sun by the outer leaves.

The leaves are also brown and NOT crispy.

Also indication of sunburn rather than dehydration. Dehydrated leaves turn brown and crispy. Sunburnt leaves are more grey/brown and, initially, soft but will soon die and dry out.

The damaged leaves are dead or dying. They will not recover but, when you snip the leaves off the buds at the base of the leaf stem should activate and produce new shoots in a few weeks.
If you remove the damaged leaves the inner leaves will be exposed to sun so make sure the tree is protected initially. If you can arrange for just a few hours of morning sun initially then increase exposure an hour or 2 every few days until you get to your desired sun exposure they should have time to adjust.

 

[arctic107]

Yes, I agree with your assessment, Shibui! The last picture sealed the deal for me.

My townhouse faces east/west. The tree that I have the Japanese Maple bonsai under blocks the morning sun (and my house blocks afternoon sun from about 4pm onwards). I will try my best to gradually expose the tree to sunlight!

Do you suggest that I snip off the dead/burnt leaves today?

Thanks!

 

[arctic107]

I went ahead and cut off the burnt leaves. I don't have enough experience with this tree or Japanese Maple bonsai to know if I left partially burnt leaves that the tree will eventually shed.

The tree is beneath my big Japanese Maple in my backyard and well sheltered from the sunlight. I'll keep it there for 2-3 weeks.