AusBonsai

Is the leaf on this trident maple
a. sunburnt
b. over watered
c. pest

Just moved the pot to more sunny area. Previously the tree was under partly sun shaded area.

David

My guess is water collected at the tips at one point when the sun was hitting it causing burn.
When the sun is still fairly bright, avoid wetting the leafs, especially if the leafs are still soft.

Always hard to diagnose at a distance but I think the change to brighter sun has burnt the leaves that are adapted to a shady area. New leaves that grow will be adapted to the brighter conditions and will burn less.

Sorry denis - Water drops burning leaves is a myth.

shibui wrote:Sorry denis - Water drops burning leaves is a myth.

Second this.

Cheers,
Mo

Thirded. Water on leaves can be a good thing, think foliage watering in Junipers for instance.

shibui wrote:Always hard to diagnose at a distance but I think the change to brighter sun has burnt the leaves that are adapted to a shady area. New leaves that grow will be adapted to the brighter conditions and will burn less.

Sorry denis - Water drops burning leaves is a myth.

A myth?? Really? I have never watered in the sun for that reason. Great news!!

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I water either at night or early morning. Sunburnt leaves seen a logical answer but it has not been hot here (Brisbane) which it is very strange. I acquired a trident maple (older) from Sydney and this tree is in full sun. Leaves are fine. Maybe this tree is still young. Thanks for helping me.

David

I fourth that. Put water on your skin. As it evaporates your skin cools, same on a plant. Wet a wilted plants leaves on a hot day and 20 mins later it has bounced back.

Sunburnt leaves seen a logical answer but it has not been hot here (Brisbane) which it is very strange.

In your original post you mentioned that you had recently moved this tree from shaded area to sun. I think that is the key. Leaves that open in the shade are adjusted to shade. They are not used to sun and will burn when they are suddenly exposed to stronger sun than they are used to, even with mild temps. New leaves that open from now on when the tree is in a sunny place will be able to cope with full sun and should be ok.

Leaves on your other tree are have grown in full sun and are adapted to it so will take much stronger/hotter sun to burn them.

Maybe similar to our skin? Skin which has not had sun exposure will burn easily, even in mild sun strength but with gradual exposure the skin adjusts and can cope with stronger sun without burning.

Note that you can cut burnt leaves off if they look untidy. New ones will grow to replace the ones that you cut off. Bonsai growers call this defoliation.

Sammy D wrote:I fourth that. Put water on your skin. As it evaporates your skin cools, same on a plant. .

Im not normally a stickler but this is not actually true. As the temp of the h2o increases, so does the local temperature of the skin.


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Sorry Istangus but sammy d is correct, our bodies do this naturally it's called sweat and it's the principle of an evap cooler
Peterb

peterb wrote:Sorry Istangus but sammy d is correct, our bodies do this naturally it's called sweat and it's the principle of an evap cooler
Peterb

sammy d is correct - it is the laws of science.
The cooling effect of water evaporating is due to the latent heat of vapourisation - chemical thermodynamics 101.
Evaporation is an endothermic process, which results in a decreasing temperature as heat energy is used to convert water from the liquid state to the gaseous state.

Homer911 wrote: A myth?? Really? I have never watered in the sun for that reason. Great news!!

That's not necessarily a bad thing though, adding water will stimulate the leaf stomata to open more readily and increase the risk of water stress from transpiration if it's hot. Hence why it's good to water in the morning or afternoon when the sun is not so intense.

As to the original post, it looks like sunburn to me

[quote="tuma"]

This problem is caused by overwatering (or possibly over fertilizing but unlikely). It is not sunburn. You can see this plainly in the lower leaf with the soft, blackened water soaked tip. The leaf above this is in the earlier stages (yellowing tip). Also water drops burning leaves is NOT a myth. It is rare but it does happen. I have seen it with my own eyes on a hydragea many years ago. I am not sure of the mechanism but I would guess you need a combination of very hot dry weather, zero air movement and the right type of leaf.

I believe longd_au and treeman are right. I was at home today and watered as per usual (6am). I noticed that most of the water drops are still on the tip of most leafs around 10am. These leafs were sprung in a partly shaded sun area (only getting sunlight around 3pm) before moved to a more sunny area which get the full force of the midday sun. I believed combination of over watered and sunburn are the cause to the brown tip on the leafs. I could be wrong. I do have another trident similar to this tree but the second tree have a very minimal foliage. Time will tell.

David