If you never found the tree badly wilted, you can eliminate under-watering as a possibility, leaving the two most likely culprits as over-watering or excessive fertilizing.

If you hadn't noticed abnormal growth on individual branches, particularly wilting of individual branches, you should be able to eliminate v-wilt as a probable. If your tree dies, severing it at the soil line and looking for sections of stained sapwood and where they occur can tell you if the tree was chronically affected or if it was a recent infection. It it DOES turn out to be v-wilt - discard (don't reuse) the soil and do not compost it or add it to your gardens or beds. The pathogen can remain active in the soil for many years (10?), even without a host plant.

Al

Any blackening in the dying branches? This would be a common indicator of v-wilt in that cultivar.

Broad spectrum of genetic variation in that cultivar. Some places even sell seedlings under the generic "Coral Bark Maple". Unfortunately, this means where some of these trees thrive in full sun or dry weather, others need a bit more protection.

Al has more experience than most of us combined, and I'd be inclined to go with his initial thought (over watering/over fertilizing).

The tree is obviously stressed, so an additional measure that might help is to move it to a more shady area that's protected from the wind. This would eliminate another couple of stressors.

An option might also be to prune one of the dead branches. Look at the cross section of the cut branch. If you see any black or brown concentric rings (sort of following the growth rings), this would be another indicator of v-wilt. You can also split the branch longitudinally and look for black or brown streaking in the wood (another indicator of v-wilt). Only way to know for sure if v-wilt is present is to take a sample to an extension office.

Blake

To me your tree is badly sunburned. You need to move it out of the full sun location. The roots are still in the condition they were when you planted in your barrel and are limited in the amount of water they can uptake to the five gallon of roots you purchased. Be sure when you water to water directly on the five gallon size of the roots. If you move it into the shade and water that way your tree will recover. Al

Based on the additional info, I'm going to guess you have a combination of fertilizer burn and sun burn.

I think there's a couple of things going on here. Container culture is very different than planting in the ground, and even If planted in the ground I wouldn't plant a Japanese Maple in a mixture of 50% compost. My guess would be your tree was showing signs of fertilizer burn from the compost, and the high temps aggravated your already stressed tree. I believe I remember reading that when nutrients are too high in the soil, a plant isn't able to absorb water from the soil. With the high temps the tree needed even more water but couldn't get it due to the nutrient imbalance.

At this point, if I'm right, I think your only option is to get the tree out of the compost mixture.

Did you bare root the tree when you repotted or did you pot up ( ie take the tree out of the pot, loosen the out side roots and pot into the large container placing the compost mix around the existing mostly intact root ball?

Reason for asking is, if you only potted up you can likely plant the tree in the ground for this year or pull the plant out of the compost mixture and pot up using a soil with similar soil characteristics as the soil in the root ball. Be careful and try not to disturb the roots any more than necessary. You're getting late in the year to be potting up but leaving the tree in the compost is likely to do more harm. Also keep the roots moist as best as possible during the procedure. If the roots dry out, they'll die and cause even worse problems. The tree should be moved to a shady area protected from wind, after or during the pot up/planting, until it begins to improve.

Also a note on full sun, some cultivar of Japanese Maples are listed as capable of being planted in full sun. This is a misnomer because full sun in Japan, western Washington, or even in the north east is different than full sun in California, Texas or Georgia. Although some of the Sango Kaku's are among the more tolerant of sun exposure when planted in the ground, I've read many examples of these trees showing sun exposure stress symptoms when in hotter climates in containers.

Hope this helps, and also hopefully one of the others will come along and correct me if I've given information that's too far off the mark.

PS The above recommended procedure would only be a temporary fix. Next spring, just as the buds begin to swell, the tree would need a full repot into an appropriate container medium if you wanted to put it back in a pot or keep it in a pot which ever the case may be.

Blake

The issues raised by sun exposure and repotting or moving a Japanese maple in a hot climate is very interesting to me.

This spring, we moved a really fine lace-leaf style Jmaple from our river lot, where it was an understory tree, into our back yard on the south side of our house where it has mostly sunshine until very late in the day. It had an immense root ball on it, which we'd half dug out in various stages during the cold season last winter. We were a little later than I wanted getting it totally dug up and moved, but we had to do it when we had the means and the help.

So this tree, which is probably 12 feet tall, was pruned just before it put out any leaves. I removed all injured limbs, and as the leaves came out, I kept an eye on them for any signs of burn or scald. I did not fertilize the soil, our hole was very big, and the existing soil in this new location was really good and similar to the spot where the tree felt at home.

I've been very concerned that it not get stressed by the heat. I mist it a lot, and have a large area of pine straw and oak leaves mulched around it. The real heat of summer is only just begun, and the tree is a bit sparse in leaves, but I'm hoping it will make it. About 3 years ago, I planted a much smaller Jmaple in the same general area of our yard, and it is now like a fat short round butterball, with seemingly no problems. It is located a wee bit closer to the neighbor's oak trees, but its soil is not so good, since there was a lot of shell left from a driveway when we dug this tree in. It has to be a totally different species of Jmaple though. I wish the metal tag that was on the recently moved tree was still there, but it was lost somehow after Hurricane Katrina nearly wiped out our entire garden. This 12 foot tree is one of the prized plants that we were able to save. If we can keep it going until this winter, maybe it will recover during the cold season, and really show its stuff next year.

Here is the top of the 12 foot jmaple
{{gwi:42524}}

And here is the short fat round one about 20 feet away.
{{gwi:42526}}

Hi Moccasinlanding,

You've got a couple of really nice trees there.

Sun and heat tolerance between different cultivars of Japanese Maples, like sun tolerance between different varieties of many plants, varies greatly. Some cultivars being better suited for more sun exposure and/or hotter and humid climates.

Without knowing your specific cultivar I couldn't do any research into whether your 12' tree will hold up under full sun or not. My guess, and it is a guess, would be that if your tree is a cultivar that will hold up to the sun exposure, heat and humidity of your area, it will probably pout a little while adjusting to being exposed to more sun. I can't believe the tree would be able to move from being an "understory" tree to full sun without some adjustment. The amount of pouting is likely to depend on the amount of fine roots lost during the transplant and the health of the tree prior to the move.

The original poster had asked about a "coral bark maple" or Sango Kaku. There are many posts on this forum and others about the variability of this specific cultivar. Some do better than others. Many in hotter climates get sunburn and summer die back with Sango Kaku even though it is typically listed as a "full sun" tree.

Of course your tree may be just fine. I recently obtained a tree, which lost most of its roots when dug out of the ground. I potted it into a free draining soil, heavily pruned the top, and babied the tree for the first month or so, and it is now my most vigorous tree.

Obviously, the "short fat round" tree appears quite happy.

Blake

I cut a few branches off yesterday, and didn't find any black rings in the cross section, so I assume it's not v-wilt. Thank god. so there's still hope.

Blake, I did the potting up as you described. When I planted the tree, it was root bound. If the composite is the issue, wouldn't the yellowing appear quickly? the yellowing and wilting only appeared recently, after 3 months of planting.

Right now, I'm suspecting the fertilizer I applied is to blame. Three days of 98 degree shouldn't do that to a tree. I'm going to apply 3 gallons of water a day to water down the fertilizer to see if it helps. Digging it out in this weather might kill the tree. I give it a week or so to see if it helps.

oldgromit,

Not finding brown or black streaking in the wood is a good sign. Doesn't guarantee anything, a recent article I was introduced to, said some trees die from v-wilt without showing signs. However, there is ample evidence in this forum and others that Sango Kaku typically does turn black or has black streaking when infected with verticillium.

A quick search of this forum and a couple of others I read turned up this information about fertilizer burn in general and using chicken manure compost with Japanese Maples.

Signs of Fertilizer Burn:
Excess fertilizer will burn roots. Affected plants will usually develop yellow foliage and may exhibit signs of nutrient deficiency. If new roots don't develop to replace the burnt roots, the plant will brown and die. Leaf margins may brown first. Browning of leaves may be all at once or may occur in spots or dapple leaves. See the third picture in your original post; yellow leaves, some with brown margins and spotting/dappling.

About chicken manure compost use with Japanese Maples, I found this:
Chicken manure compost tends toward alkalinity, Japanese Maples like acidic soil. Most recommended mixtures for Japanese Maples involve a large percentage of pine or fir barks/composted pine or fir bark. Even organic fertilizers (chicken manure falls in this category) can burn your plants, marketing claims to the contrary. I even found one comment which stated categorically, "never used composted chicken manure in container culture with Japanese Maples". Quite a strong statement, the merits of which can be argued by those who care to argue or can back up their arguements.

For my part, learning chicken manure compost tends to be alkaline, knowing it is a fertilizer and knowing that even when planting in the ground most places I found in a quick search only suggest using less than 25% compost (of any kind (this would include more acidic compost like pine and fir bark composts), I still think you've got that tree in a container with too much fertilizer. Adding additional liquid fertilizer made the symptoms worse, indicating to me that you were already burning roots from the compost.

In the end it's your tree and your decision.

Good luck with the tree.

Blake

Blake:

Thank you for your point that all "full sun" is not alike. For some reason, this just did not occur to me. I'm a native of Puget Sound but live in Oklahoma now, and the change in terms of climate could not be more dramatic. The temps hit 100 before Mem Day here and have not slackened. I'm about to purchase my first JM (Fireglow) and although the nursery is emphatic about morning sun, only, I have definitely noticed many claims (from other sources) that JM's can take sun all day. I've been scratching my head over that one; it never occured to me that they might be using a cooler climate as their template. Sure, all day sun in Tacoma, but here? When you have to safely ensconce in air conditioning by 10 am? (And I'm tough.)

Thanks for the tip.

Hi Oklahomarose,

Thank you for the kind words. Fireglow is a beautiful tree and I'm sure you'll enjoy it.

However, in this case, Fireglow usually can stand up to full sun even in high heat and humidity. According to "Essence of the Tree", Fireglow was developed in Alabama and does well in full sun even in southern heat and humidity. I'm not sure why your nurseryman would say otherwise, but I am plenty willing to defer to his knowledge of local growing conditions.

Perhaps, depending on the size of the tree you'd like to purchase, you could leave it in a nursery pot/pot up a time or two over a couple years until you find a spot that both you and your tree can live with (so to speak).

For what it's worth, I have my Fireglow in about 6 hours of Olympia sun each day and it is still holding its plum coloring very well (even in this cooler and wetter than normal spring we've had this year). Although, I should point out my Fireglow is in a container and I'm sure it heats up more than if it were in the ground.

I hope you enjoy your new tree.

Blake

Moccasinlanding,

Once I got home, I was able to do a little searching for more info on green lace leaf Japanese Maples. The good news is, most of the 20ish I read about say they are able to handle a wide variety of sun exposure from full sun to mostly shade. So your tree should be able to adjust to its new home. Of course with over 600 cultivars of Acer palmatum alone there's no way I could search all the dissectum (lace leaf) cultivars, so there's always that chance.

Sorry oldgromit, I hope you don't feel we've high jacked your thread too much, but the other questions were still sort of on topic, being about sun exposure.

Blake

So this weekend I moved heaven and earth, well, earth only, and dug out the japanese maple. I'm shocked to see there is no root extended from the original root ball. I mean, after lose the surrounding compost, I literally pulled up the tree from the barrel without any resistance or effort. The root ball from the original plastic container is still enclosed in the clay dirt and zero root coming out of it... damn...I assume after 3 months of planting it, and from a bare tree to one with green leaves then yellowing leaves, it should develop some new roots and extend to the dirt I added. did I do something wrong? I remember when I planted it three months ago, I squeezed the plastic container, and pulled out the tree, then put it in the hole. Did I miss a step or two? That's what the instruction said. Do I need to lose the dirt first?

After the initial shock, I lose up some of those hard clay surrounding the root ball, and put it into a bowl of water and let it sit overnight, then planted back with some commercial potting mix.

What will cause the root not developing anything in 3 months, and did I re-plant it correctly?

A couple years ago, the landscape architect where I work got a bunch if us involved in planting some street trees with one of the local municipalities for arbor day or tree city or some such event. Anyway, as part of the "planting instruction seminar" put on by this municipality, they showed us pictures of street trees that were probably 6-8" diameter that had to be replaced because they blew over in a storm. The root ball on these trees was probably 2-3' in diameter and all the roots were growing in a circle. No lateral spread of the roots because the trees were planted wrong.

I said all that to say they told us the "proper" method for planting the trees was to dig a hole twice as wide as the spread of the crown of the tree, pull the tree out of the pot, loosen at a minimum the outer 2-3" of the root ball, spread the roots out in the hole and back fill, then stake.

It's hard to say for sure without knowing more about how you potted up the tree, but if you didn't have any new growth outside the original root ball, I'm guessing you didn't get the outer edge of the root ball loosened and spread out to grow in the new medium.

Tree roots need to "breath" believe it or not, so I hope leaving the roots in water over night didn't cause even more problems for your tree. Only time will tell.

If you were able to loosen the root ball enough so the roots have an opportunity to spread out in the new soil, you've probably done as much as you can do for now. Hope you took the opportunity to move the tree to a more sheltered position while changing the container medium. You'll also need to watch your watering very closely for the rest of this year. "Potting soils" require a bit more work to keep potted plants happy. There's no need to fertilizer the tree the rest of this year. Tying some twine from the tree to the edge of the container will help stabilize the tree and help to keep the new roots from breaking.

Like I said before, if the tree survives, I'd recommend bare rooting and repotting into a better medium for containers. A little searching around in the container forum should give you some good information on good container soils. They are affectionately called "gritty mix". There's two basic varieties. One that last a little longer between repots.

Good luck with the tree.

Blake