discolored foliage

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WendyLW
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Joined: March 29th, 2020, 3:58 pm
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discolored foliage

Post by WendyLW »

Hello, I am new to this forum so hoping someone can point me in the right direction.
I have a bonsai plant that was bequeathed to me last year. It is very old and very special so I hope I don't lose it.
In recent weeks the foliage has started to discolor - turn yellow, and is fading quickly these past few days.
I have had the plant in a sheltered position for summer and moved it into a more open position this week - getting beautiful morning autumn sun in Melbourne Australia.
I water lightly every couple of days.
I have posted pictures from 5 days ago, showing the problem.
And a couple more today with plant details and state of plant today.
Should I feed? Water? Move?
All of the above?
All advice welcome.
Thank you in advance, WLW
bonsai1 22032020.jpg
bonsai2 22032020.jpg
bonsai3 22032020.jpg
bonsai4 22032020.jpg
bonsai1 29032020.jpg
bonsai2 29032020.jpg
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shibui
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Re: discolored foliage

Post by shibui »

There can be a number of reasons for evergreen foliage to change colour. in order of probablility:

Too dry - even just one day with not enough water can do it. Trouble with evergreens is that the damage does not show up for several weeks after by which time you have usually forgotten you di not water.

Not enough light - Leaves need plenty of sun so they can make plant food. If the leaves are not getting enough light to work well the tree will not waste resources and will shut off supply to the shaded ones and they will die. Inner, back and lower parts are most affected most as they tend to get less sun.

Pests - mites are tiny sucking insects, barely visible but when they breed up they can suck enough sap out of the leaves to kill some. Place a piece of white paper under an affected branch and tap the branch to dislodge bugs and poop. Look for tiny black dots on the paper. If unsure a good miticide will not hurt the tree and may just cure the problem.

Old foliage dies naturally - All leaves have a finite lifespan. evergreen leaves live for 2-3 years then die while newer leaves take over. The older leaves tend to be closest to the trunk so if inner leaves start to turn brown this may be a natural cycle.

Starvation - When nutrients are scarce the tree will shut off some leaves so the rest of the tree can survive. Location of the changed leaves will depend what nutrients are most lacking but often affects older, inner leaves most.

Physical damage - often seen a few weeks after wiring when sap flow was damaged by over zealous bending or after a tree has fallen on the ground. Damage may not be visible but sap flow is restricted or stopped so a whole section of a branch will die.

Too wet - sounds strange that this can cause the same effect as too dry but when the roots are constantly too wet they can rot then the tree cannot get enough water even though the soil is wet.

As you an see there are plenty of options that could cause these colour changes. You know the tree. Do any of them sound possible?
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tgward
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Re: discolored foliage

Post by tgward »

as with Shibui . Depends what you mean by 'lightly watering' --after watering next time I would let it drain (make sure the holes aren't blocked) for a while then remove from the pot and check to see if the root ball is damp enough or too wet.If still too dry you may need to immerse in water until the bubbles stop.then allow to drain
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Re: discolored foliage

Post by baldtwitlion »

Hi
I have had one of these for about 5 yrs and have noticed that during the year the foliage in areas will go yellow and they do come off quite easily
Mine is in full sun and treated the same as all my other plants and appears quite healthy


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treeman
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Re: discolored foliage

Post by treeman »

Watering is one of the most difficult things to get right. It takes time to learn it but the best guide is this. A tree which has been potted for at least one year should dry out regularly at the roots (potting mix) If it does that, it means the roots are very healthy and active. A healthy tree should generally need watering every day due to dryness or if in a more protected position, every second day perhaps. If you water it well (soaked) and it does not dry out in a short amount of time, there is a problem in root area. Either 1/ the pot was too big from the start, 2/ the mix is too fine, 3/ The tree was over watered and the roots rotted or 4/ It dried out and the roots died and rotted after the next watering.
These ''commercial'' trees are usually potted in inferior mix. If you want to do bonsai long term you will need to make up your own mix and learn the art of watering. Hinoki should have firm glossy foliage, if it has lax dull leaves there is something seriously wrong. Take it out of the pot and look at the roots, Look for healthy roots - light brown with white tips. If you find dark brown roots they are dead or dying. It's ok to repot now. You have not picked the easiest tree in the world to maintain, but if you repot in a good mix and place it in full sun (shade in summer) it should recover slowly. I would use a slightly smaller pot. Back plastic or terra cotta is ok until it recovers. Make sure you stake it so it does not move. And get rid of those damn black pebbles so you can see the soil surface as this will let you know if it's dry or not. Never keep it indoors. EVER! even for 3 hours.
Mike
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