Japanese Maple wilting

[NathanJB]

Hello all,
I'm looking for some advice on my naple bonsai. I've recently noticed areas are turning slightly brown and look as though they are wilting. Areas affected seem to be around the edges for the moment, but I think overall all the leaves are looking paler than it did a week or so ago.

It has been moved to a more open spot so wondering if it's too exposed?

It was repotted early spring.

Any help would be appreciated.

 

[NathanJB]

This is the tree a week and half ago

 

[baron]

Seems like a little bit too much sun

 

[Shibui]

There is definitely a change of colour but I can't see any wilting shoots but then, there does not seem to be any long, new shoots growing? Maybe you have been really good with nipping buds or maybe the tree is not getting enough food or water.
I can see a couple of leaves that look a little burnt - brown patches. That would probably indicate lack of water or too much sun.
If you moved it after the leaves were open it is more likely they will burn. Leaves adapt to the conditions so leaves that are accustomed to cool shady spot and are suddenly moved to more sun will often burn. New ones that grow in the sunny area are usually fine.

Your profile gives no indication of where you are. I assume northern hemisphere as the tree appears to be spring/summer but a location can give some good clues to help us give better targeted advice.

 

[NathanJB]

Thanks for the response. I'm in the UK so its spring here at the moment. I did move it whilst it was in full leaf, from a shaded area as well.

 

[Shibui]

JM are not known for sun hardiness but there are degrees of sun. Different sun strength here to where you are probably so it is hard to advise properly. Mine definitely need more than part shade in summer when temps are often above 40C. Even where you are some shade in the heat of summer is probably needed so if that spot is full sun all day maybe look for a little more shelter from afternoon sun.
Does this spot get full sun all day, part day, some shade some times? The move from shade to sun will damage some (maybe many) of the existing leaves but usually new ones will be hardier. I just can't see much growth at the moment so I hope it can grow some new leaves.
Proper watering - enough to make sure the entire pot is properly wet - is important. Often a one off sprinkle with the hose or water can is not enough to wet right through. Even when you see water coming out the bottom, most is probably seeping around the edges and not soaking right to the centre. Water the pot well then come back 5 or 10 min later and water again for better penetration right into the root mass. Once a week soak in a tub of water in summer (as well as daily watering) can also help make sure the tree gets proper watering.
Even with good watering, in hot areas JM just cannot send enough water up the trunk so that's when shade is needed to balance water with sun.

Good news is I don't think the tree is dying. Just having a little trouble coping with the new spot.

 

[NathanJB]

Would u suggest moving it back to a more shaded area?

 

[Deleted member 21616]

It was repotted early spring.

Did you keep any pictures of the roots before and after you pruned them?

 

[NathanJB]

I didn't I'm afraid

 

[WNC Bonsai]

The curator of the bonsai at the arboretum keeps some in a cold room until late spring then allows them to bud out in full sun. He says this allows the leaves to acclimate to a full sun regime like they face on the display benches. If they are allowed put leaf out in the early spring they burn when placed in the sun.

 

[0soyoung]

Quite true, @Cofga, but it is the sudden change in light levels that is the primary problem. A shade-adapted a.p. progressively moved to sunnier exposure won't have a problem (you or I might because it is a tedious procedure over several week's time).

btw one can use this fact to intensify fall colors. Move trees into more shade 4-6 weeks before the expected fall coloring time in your area, then pop them into more sun.

 

[NathanJB]

Thank you, I've moved it to a more shaded spot so hopefully it will recover. Are the damaged areas likely to die off?

 

[0soyoung]

No, not unless they are already showing a lot of brown. Then the leaves will fall off and likely you'll get a new flush of leaves after a few weeks. That is about it.

Chlorophyll is in complex organic things call photocenters that are big photon antennas. In shade they get bigger and collect more incoming photons. If they are then in too much sun the photocenters get overloaded and may be damaged. Red pigments, anthocyanins, are made to shade the photocenters and protect them by reducing the incoming light level. Yellow xanthophylls serve a similar purpose, but do so by diverting the energy away from the photosynthetic apparatus. Over time, it all gets readjusted to the tolerable light levels and the normal coloration will return, but sometimes the change in color lasts all the remainder of the season.

 

[NathanJB]

Thank you all for your advice. One last question, how often should I be feeding the tree?

I have Naruko 5-5-5 Bonsai Fertiliser which I usually apply a small amount once a month in spring and summer.

 

[rockm]

Thank you all for your advice. One last question, how often should I be feeding the tree?

I have Naruko 5-5-5 Bonsai Fertiliser which I usually apply a small amount once a month in spring and summer.

Woefully inadequate fertilizer and dosage. most bonsaists use regular 10-10-10 plant fertilizer that they get at the discount store. Specialized "bonsai" fertilizer is usually marked up 100 percent and is weak, as your is.

I "feed" my trees (including my Japanese Maples) full strength once a week from late April to early October.

 

[NathanJB]

Any recommendations on types of fertilizers?

 

[rockm]

Any recommendations on types of fertilizers?

Whatever regular, all purpose 10-10-10 fertilizer is on sale--Miracle Grow works well, Peters etc.

 

[Shibui]

"A little bit once a month" is not very specific but does sound inadequate. As noted right at the start the tree looks poorly fed. Healthy JM at this time of year should have plenty of long new shoots all over (or stubs where they have been pinched off).
None of my JM can read fertiliser labels so they don't care what sort I give them. All they are interested in is the nutrients and all fertilisers have nutrients so use whatever you have available.

5-5-5 and 10-10-10 are the same thing just that the first is only half as strong (more non nutrient 'filler' to pad it out). Not sure what the recommended rates are for either but if the manufacturers are recommending correctly the rate of 5-5-5 should be twice the 10-10-10 which will deliver the same dose of nutrients. You just go through the weaker one twice as fast.

 

[BonsaiNaga13]

How long have you had the tree?

 

[NathanJB]

How long have you had the tree?

1 year and 3 months