Three Arakawa Maples, Two are not healthy

I have some problems with a couple of my arakawa maples. One, which is grafted, is doing great. Two which are on their on roots are having issues. I had problems with whiteflies so I have sprayed them a couple times with Bayer 3-in-1, and with Cleary's fungicide. Pics are attached. The two on their own roots were bought this year and are in small basket and a wooden box. One is in Boon's mix, the other in a bark based bonsai soil. They are about 12 inches tall.

The grafted was bought a year ago and is in a much larger terra cotta pot with a mix of potting poil, turface, and pumice. It is about six feet tall.

All three are sited together and get the same amount of sun and wind.

I would appreciate suggestions on what's up with the two with problems. Is this fungus, insect damage, ....???

Thanks

Did you spray all 3 of the trees with the same chemicals?

Were the leaves like this BEFORE you sprayed?

Jim, yes the were like this before. And yes, I sprayed all three with the same treatments.

Thanks

Were any of them repotted this year?

I don't know about the first, but the second definitely looks like it could be a root issue. Not necessarily root rot; perhaps the roots aren't taking up enough enough water which is why I asked about repotting. Which soil mix is the second tree in?

The first pic I see a purple stem, typ. that's pseudomonas from overwatering. Though I don't see that in the second pic. Have you had a problem with the soil staying too wet?

coh, The first one was repotted this year into Boon's mix. It is Ina wooden training box I built. The second was not repotted. It is in a pond basket in a soil mix with some bark- came that way from the vendor.

fore, yes they tend to stay wet. I have a chopstick In them to check watering.

Thanks

Frank

Do you site these trees in a windy area? Wind desiccation is common for a thin foliage tree like maples. In as little as an hour, even a moderate breeze can cause damage. Obviously, the leaf is permanently damaged and only defoliating can restore the foliage, (it's too late, seasonally). I don't think I would use a pond basket for growing a maple, though. Maybe the drainage is a little too good! Perhaps the wooden box your using for the first one is holding too much water? Maybe tilt the tree out, drill a few more holes, screen 'em off and see what happens? I'm developing a nishiki-gawa in a wooden grow box and it to displays these same burnt edges on some foliage. It's still putting out new growth with no signs of fungus or airborne marauders. So, methinks the first maple has some dead roots causing the leaves to blacken and maybe the second is suffering from leaf-scorch? Just floating some of my own experiences out there, maybe it'll help you a little. Good luck and have a great weekend!!

The problem shown in the first picture looks more like a fungal infection, and the rest are similar to the problems caused by low humidity air or soil or presence pests. The tips of the leaves can dry up because of the salinity of the soil (as the photo number 3).

I have tried Acer palmatum 'Arakawa.' It is extremely temperamental. I think your basic problem is trying to grow it on its own roots. I believe it will only survive or at least thrive if it is grafted. I suspect the roots have the same gene as the rest of the tree for excessive bark, and therefore are unable to function properly.
Iris

The Rough bark Japanese maple, Acer palmatum 'Arakawa,' grows well on its own roots. I've been rooting them for over 35 years. Cuttings are preferred over grafts for bonsai training because the entire plant is genetically identical and the surface roots will develop rough bark. Here are a few photos of my bonsai Rough Bark Japanese Maple in winter and autumn color. Also attached is a photo of my Rough Bark Japanese Maple garden tree. It is from the same batch of rooted cuttings about 35 to 40 years ago. The bonsai next to the garden tree is the same as the first photos and the same age. The garden tree suddenly grew fast and is now about double the size. A heavy surface root also has thick rough bark.

Once established this cultivar grows well on its own roots. I also have a cutting from the garden tree next to my home. It grew shoots oner 24" in length this summer.

In that case, I may try one of yours. I have developed a better soil mix, which may help.
Iris

The first Arakawa I posted is from Bill V.

Frank

Is that the one with damaged leaves? At least we know that Arakawa succeeds in Rochester, which is in Zone 6, next to a lake. Syracuse is in Zone 5, but sunny days in summer can be hotter and drier than Rochester. Georgia is certainly hotter than Rochester. These clues may be a red herring. I would like to hear from other people who have grown Arakawa elsewhere.
Iris

All three of my Arakawa are sited in the same location. They are on a patio tat gets dappled sun until noon then shade after noon. They are protected from wind. So I don't think wind or heat is the issue, since the third photo shows a healthy Arakawa.

Maybe Bill Valavanis will speak up since the one of the Arakawa came from him as a rooted cutting.

Frank

I'm guessing it is the soil mixes used for the trees. Maples generally like a soil with more moisture retention. A guy in my club grows his in just akadama. I got one from him and put it in half akadama half pumice and wind tore the leaves up badly, even watering two to three times a day if needed.

You say nothing about fertilizer applications, what and when.

The first tree looks like a fungal (or maybe bacterial) problem, but the leaves also appear chlorotic – a pinch of iron sulfate or chelated iron will cure chlorosis. I am guessing this is the one potted in a ‘bark based bonsai soil’. Bark is known to scavenge nitrogen if it hasn’t been composted. I would think seriously about putting this tree in a different medium, unless you have used this mix successfully before.

The leaves on the second tree just look wind burned. Otherwise the tree looks healthy – see those buds on the trunk? This tree appears to be in Boon’s mix. I would say that you either need to water more frequently or change to a more water retentive mix. I grow JMs in pure Turface MVP. When the weather is hot and dry, I dress it with damp sphagnum to cut down on evaporative loss.

The last thought I have is to question whether root temperatures are equal with all three. You can check this by sticking a simple meat thermometer in the medium of each (do this close to the hottest time of day). JM roots don’t grow (and so neither does your tree) at temperatures above 90F. This might be a factor affecting the first tree. The possible remedies are many, but amount to shading the pot and making a swamp cooler. To a certain extent, damp sphagnum top-dressing acts as a swamp cooler – a light colored towel wrapped around the pot and covering the medium is shade and a swamp cooler.

0soyoung wrote:I am guessing this is the one potted in a ‘bark based bonsai soil’. Bark is known to scavenge nitrogen if it hasn’t been composted. I would think seriously about putting this tree in a different medium, unless you have used this mix successfully before.

This one - the first picture in my original message here-  is in Boon's mix. It came from Bill V in a small nursery pot. I removed the soil and repotted it in Boon's mix this spring. It has a tendency to stay wet so I don't water it daily.

0soyoung wrote:The leaves on the second tree just look wind burned. Otherwise the tree looks healthy – see those buds on the trunk? This tree appears to be in Boon’s mix. I would say that you either need to water more frequently or change to a more water retentive mix. I grow JMs in pure Turface MVP. When the weather is hot and dry, I dress it with damp sphagnum to cut down on evaporative loss.

. This one - the second picture- is in a bark based mix in a pond basket. It came that way from Martin Sweeney.

Both have had issues with whiteflies this season. I have used Bayer 3-1 and imidicloprid granules with an occasional mild spray and rinse with a "natural" castile type soap. The healthy Arakawa was given the same treatments.

Rather than having us do long-distance diagnosis (and we're all probably wrong, just basing opinions on a coupe of photos), take the plant it to you county agricultural extension office. They'll tell you what the problem is.

I would not worry about the foliage, its the end of the season.

Next spring I suggest applying daconil to control fungus problems.

Bill

Bill, Thank you. Would you use daconil or lime-sulfur as a pre-winter treatment before I put them up for the winter?


Frank

Use both treatments. The trees need plenty of air circulation, fast draining soil and good sunlight for best growth. These maples really are easy to grow.

My large garden tree produces hundreds of self sown seedlings. Diane alone collected over 300 this spring. I have a four year old SEEDLING which actually came up in a bonsai pot with a juniper and now has rough bark ALL over the trunk and branching. Might be interesting and I'm carefully watching it.

Bill

William N. Valavanis wrote:Use both treatments. The trees need plenty of air circulation, fast draining soil and good sunlight for best growth. These maples really are easy to grow.

My large garden tree produces hundreds of self sown seedlings. Diane alone collected over 300 this spring. I have a four year old SEEDLING which actually came up in a bonsai pot with a juniper and now has rough bark ALL over the trunk and branching. Might be interesting and I'm carefully watching it.

Bill

Hi bill,

Would love to see a picture of the maple in he juniper pot. I has noticed the bark change quite fast on my arakawa as well. Do your maples get full sun all day or so they get shade, by trees or cloth? My maples grow well all spring and then the leaves look a little tired by the end of the summer.

Tom