Why are the leaf tips dying on new shoots on my A. Palmatums???

[caerolle]

I have several very small trees I up-potted after receiving them from the nursery (about a month ago), and while most of them are doing well (including the red ones, which are doing the best, oddly), two of the green ones keep throwing out little sprouts but then the ends shrivel and die as seen in the attached photo. In the end the entire leaves die and the whole shoot dries up. Hard to get any growth this way.



These trees are both in the shade and only get sun for an hour or two in the afternoon.

I have all my life struggled with how wet plants need to be, and of course they wilt and die if you underwater them or overwater them, so I have a hard time figuring out what is going on. These trees are in a 1:1:1 mix of pumice (1/10 - 1/5"), fir bark (1/5 - 1/4"), and leaf compost (1/5 - 3/8"). This mix drains really well, and also holds moisture well. I am watering all the trees the same way at the same time. Also, I am feeding once a week with 20-20-20 plant food diluted to 1/2 strength. I feed the same way I water, keep adding until water flows from the bottom for a few second.

I did read the thread linked below, and perhaps my issues are related, but I am in middle Indiana and not Florida, so should be at least a little cooler. Plus, as I said, these trees are mostly in the shade.

I appreciate any help or advice!

Thanks!

 

[NOZZLE HEAD]

Could be just the heat, if it has gotten really hot in your area.

It could also be the fertilizer “salt burn”. I’m a big fan of triple twenty. I sell it thousands of pounds of it at my day job, but it is a “high salt” fertilizer. I’d lay off it for a couple of weeks and see if it helps, if you have been fertility all along the trees nutrition wind be affected much.

Also that compost holds on to moisture really well, as well as that fertilizer.

What mix rate have you been using for that triple-20?

 

[caerolle]

Could be just the heat, if it has gotten really hot in your area.

It could also be the fertilizer “salt burn”. I’m a big fan of triple twenty. I sell it thousands of pounds of it at my day job, but it is a “high salt” fertilizer. I’d lay off it for a couple of weeks and see if it helps, if you have been fertility all along the trees nutrition wind be affected much.

Also that compost holds on to moisture really well, as well as that fertilizer.

What mix rate have you been using for that triple-20?

It has gotten really hot starting today (mid-90s and supposed to be that way for days), but hadn't been that hot, IMO.

This is the loose blue crystal stuff (Schultz) like you get at the home improvement stores, not the granular field fertilizer (I grew up on a farm, lol). I mix 1 heaping tsp per gallon of water. I do worry about salt burn, but some of my trees are doing fine with the same treatment, as mentioned below.

The thing is, I have a new sprout on each of a couple other green cultivars, one of which is in the direct sun, and both are doing ok. The one in the direct sun has one little sprout and the one in the shade has a shoot that is getting vigorous. And I have three Shin Shishio trees of the same size right with the two green cultivars that are being a problem, and one has several little leaf sprouts, and the other two quite a lot of vigorous sprouts and little shoots. I would have expected the red ones to be more of an issue than the green ones, so a puzzle. All are 1/4 -1/3" in diameter, and about 2 feet tall, so pretty similar trees.

The two trees giving me problems both have only a few branches, which are up high, and don't have a huge number of leaves. I am wondering if these trees are just a bit weaker and trying to get their feet under them. I think I am going to start watering them once a day instead of when they seem dry, and see whether that helps or hurts. Seems pretty clear that trying to make sure I don't overwater them isn't doing the job.

Thanks!

 

[NOZZLE HEAD]

It has gotten really hot starting today (mid-90s and supposed to be that way for days), but hadn't been that hot, IMO.

This is the loose blue crystal stuff (Schultz) like you get at the home improvement stores, not the granular field fertilizer (I grew up on a farm, lol). I mix 1 heaping tsp per gallon of water. I do worry about salt burn, but some of my trees are doing fine with the same treatment, as mentioned below.

The thing is, I have a new sprout on each of a couple other green cultivars, one of which is in the direct sun, and both are doing ok. The one in the direct sun has one little sprout and the one in the shade has a shoot that is getting vigorous. And I have three Shin Shishio trees of the same size right with the two green cultivars that are being a problem, and one has several little leaf sprouts, and the other two quite a lot of vigorous sprouts and little shoots. I would have expected the red ones to be more of an issue than the green ones, so a puzzle. All are 1/4 -1/3" in diameter, and about 2 feet tall, so pretty similar trees.

The two trees giving me problems both have only a few branches, which are up high, and don't have a huge number of leaves. I am wondering if these trees are just a bit weaker and trying to get their feet under them. I think I am going to start watering them once a day instead of when they seem dry, and see whether that helps or hurts. Seems pretty clear that trying to make sure I don't overwater them isn't doing the job.

Thanks!

Sounds like a good plan.

I Understood you were talking about the solution grade triple-20. Out here in Oregon we grow a lot of weird crops in weird ways that require weird fertilizer, so ya I have costumers that buy that crystal stuff by the pallet.

 

[One First Matter All]

It looks like a fungal infection to me, likely anthracnose. The same thing happened to my Trident Maple (also in Indiana) this year. If the new leaves are deformed, shriveled, and/or blackened, and the tips of the old leaves appear dried out, then it's probably a fungus.

 

[One First Matter All]

Check out this thread: https://www.bonsainut.com/threads/bonsai-fungus.28631/

 

[caerolle]

It looks like a fungal infection to me, likely anthracnose. The same thing happened to my Trident Maple (also in Indiana) this year. If the new leaves are deformed, shriveled, and/or blackened, and the tips of the old leaves appear dried out, then it's probably a fungus.

Yes, someone else PMed me with the same thought, and some great detailed advice!

Thanks so much!

 

[One First Matter All]

Yes, someone else PMed me with the same thought, and some great detailed advice!

Thanks so much!

No problem. Good luck.

 

[Bonsai Nut]

Could be just the heat, if it has gotten really hot in your area

I was going to say - a combination of heat, and too late repotting leading to new bud push which burns up in the summer heat. At about this time of the year (at least in the Midwest) we are turning the corner where spring and late spring growth should be hardened off, and the tree is done with its active growth phase and instead is shifting to an energy regeneration/energy storing phase.

Could be some anthracnose as well, but the underlying issue is probably more related to timing of major tree work.

 

[caerolle]

I was going to say - a combination of heat, and too late repotting leading to new bud push which burns up in the summer heat. At about this time of the year (at least in the Midwest) we are turning the corner where spring and late spring growth should be hardened off, and the tree is done with its active growth phase and instead is shifting to an energy regeneration/energy storing phase.

Could be some anthracnose as well, but the underlying issue is probably more related to timing of major tree work.

Very good points, thanks!

 

[caerolle]

I was going to say - a combination of heat, and too late repotting leading to new bud push which burns up in the summer heat. At about this time of the year (at least in the Midwest) we are turning the corner where spring and late spring growth should be hardened off, and the tree is done with its active growth phase and instead is shifting to an energy regeneration/energy storing phase.

Could be some anthracnose as well, but the underlying issue is probably more related to timing of major tree work.

I thought on this a bit more, and I guess I have misunderstood something. I thought people pruned J. Maples in mid-to-late June, then got another set of growth? I didn't realize the hardening started quite so early...

 

[NOZZLE HEAD]

I was going to say - a combination of heat, and too late repotting leading to new bud push which burns up in the summer heat. At about this time of the year (at least in the Midwest) we are turning the corner where spring and late spring growth should be hardened off, and the tree is done with its active growth phase and instead is shifting to an energy regeneration/energy storing phase.

Could be some anthracnose as well, but the underlying issue is probably more related to timing of major tree work.

I live in the land of anthracnose, we have the perfect conditions for all the different anthracnose pathogens in the willamette valley, and those definite margins (No chlorotic verge) at the edge of the necrotic tips looks abiotic.

 

[caerolle]

Oh, btw, I thought I had put when I did various potting in the OP, but I see I didn't...

I received the two trees under discussion on June 10, and up-potted them 2-3 days later. I also received two Shin Shishios in the same shipment and repotted at the same time. I was supposed to just slip pot these, but I couldn't help myself and I tried to gently untangle and loosen the roots a little. I did not cut any roots. A little of mix from the roots fell out, which I mixed into the new mix, but I did not intentionally remove any. The two green cultivars and one of the red ones all went into the pumice/bark/compost. The other red one went into some bonsai mix I got locally, which was lava rock, bark, and Turface. To my surprise, the red tree in the pumice/bark/compost is the one growing vigorously, and the one in the bonsai mix is just starting to throw out some sprouts.

I have another batch of trees I received in late May. I up-potted these in the same way as described above when I received them, but in a mix I came to see as way too heavy. Plus, I did not keep them in the shade a couple days before I repotted them and put them in the sun. I knew it would not be ideal to repot these, but I thought repotting was probably less bad than leaving them in the mix I had them in until next year. I repotted these trees at the same time as those above. I had two Shin Shishios in that batch, too. I had initially put these in a place that got full morning sun, and a few days after I set them out, between early in the morning and about 1PM, the leaves turned to a word starting with 's.' I was watering all the trees pretty heavily, and I have no idea what really happened, but I thought it was leaf burn, so I moved these into the shade. I wound up pulling almost all the leaves off one over the next few day, and quite a few off the other. I thought the first was probably going to die, and the second about 50:50 on living. When I repotted them in the looser mix, the roots on the first were horrible, a black mess of a core. The roots on the other looked better. I put the first one in the bonsai mix, and the second in my pumice/bark/compost mix.

I guess that was about 3 weeks ago now (repotted ~June 10-11 like above). The worst one continued to die, and got down to like four large leaves and couple small ones. The second one actually started getting better almost immediately, and now has lots of vigorous growth. The worst one has started breaking buds and has several small leaves unfurling, so I think it will be ok, too.

Btw, these are all in 1-2 gallons pots, not bonsai pots. I am just trying to grow them up right now. I expect it to be 2-3 years before I even make the first trunk cut.

I had planned to repot all the trees that are in the pumice/bark/compost in fresh bonsai mix in late winter next year, but now I am not so sure. First, this is my first year with these trees, and I don't even know if I can successfully keep them alive. If I repot in late February, I guess I won't know if they are alive or dead, and I hate to spend several hundred dollars on bonsai mix for dead trees. Plus, I guess repotting would set them back yet again. Right now my plan is to leave them in the pumice/bark/compost through next year and then repot them in February 2022. Surely if I can keep them alive this winter, I can keep them alive next winter.

 

[rodeolthr]

Do be careful with the amount of inorganic fertilizer you use on your Japanese maples. It's my understanding that they can build up quickly in the containers and cause damage. Perhaps @0soyoung can chime in on this subject since I seem to remember him posting about it in the past.