Many of my maples and some of my other trees have had leaf scorch

rhawes

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I am not sure but I think it may be overwatering or environmental. I water my outside trees once a day. Watering twice would be too much. Anybody sure how to deal with this? I am in Lancaster, Pa.
 

Tieball

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Some photos might help.
It would also be helpful to identify what kind of trees you’re talking about.
 

rhawes

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I usually water in the evening and They all look good by dinner time but the tips of the leaves are dry and scorched. I will post some pics in a few.
 

PA_Penjing

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I always water my trees in the morning, they look great. My wife always waters her flowers in the evening and they look like shit. I'd start with that switch. I stopped growing maples because my bench sits in full sun, if you want to grow fragile diva trees like Japanese maple, you'll have to pick a more shaded area it sounds like, or use shade netting. There is a chance that watering in the morning will fix your problem but if they are baking in full sun all day ... experience tells me they will never look good in the height of summer. It gets hot here
 

rhawes

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I have several different kinds of maples and a cherry tree
 

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rhawes

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I have the maples in pumice with some bonsai dirt and the cherry tree the same. All but the first tree are in an opened up greenhouse with uv protection. It is opened at both ends. With good air circulation.
 
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WNC Bonsai

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It happens to mine every year this time if I leave them in the sun too long.
 

rhawes

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do you all think a shade cloth will help? Plus I will change the watering to morning.
 

Pj86

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do you all think a shade cloth will help? Plus I will change the watering to morning.
Typically it is not only the heat that causes leaf scorch. It is a combination of low humidity, high heat and dry winds. Japanese maples are understory trees, they tend to be protected from strong winds and drying winds in nature.
 

Shibui

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Burnt leaves are a result of not enough water reaching the leaves. This can be caused several different ways.

Not enough water in the soil. This can be because soil is not water retentive or because you don't water enough or both. Sometimes just ineffective watering can cause this problem. If water does not soak right to the middle of the root ball that obviously limits the amount of water the tree has to get through the day. It can take some time to learn all the nuances of watering effectively.
Also, as the root fills with roots the pot they will limit the amount of water the pot can hold so root bound trees seem to need more water to maintain health.
Type of soil will influence how much water can be stored through the day.
Watering thoroughly definitely helps trees get through hot days without burning. Watering more often helps. Note that I water my trees twice a day in hot weather to minimize leaf burn and I know others who water even more often.
Modifying the soil mix can be an option.

Hot wind and excess sun. Trees use water to cool themselves. The hotter the wind and sun is the more water a tree will use. Increasing watering or watering frequency can help or change location to reduce wind/sun exposure. Shade for part or all of the day definitely helps reduce leaf scorch. Shade cloth is easy to use and easy to modify over the seasons.

Species or variety. It appears that some trees may have limited capacity to use or transport water. I think JM fit into this group as they always seem to be among the first to burn, even though the soil may still have plenty of available moisture. The only way to deal with this is to not grow susceptible species or set up some sort of protection to modify conditions to better suit the species. Some of us probably need to accept that Japanese maple may not be suitable for our location.
 

PA_Penjing

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The greenhouse you linked seems like it offers a little bit of UV protection which is good, but anything in a greenhouse is going to be hotter than a tree outside. On a nice breezy day the temperature may be about the same but on a hot still day those trees/pots could be much hotter than the surrounding area. Not sure if it would be wiser to skip the greenhouse and lose the protection in favor of cooler temps though.
 

rhawes

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Ok I opened up the greenhouse. They all only have partial sun because they are on a balcony. And I will water twice a day to see if that helps. Thanks all!!!!
I think maybe some of the hot air from my ac was blowing towards the greenhouse too. So maybe opening it up will help. Thank you everbody for your input!!!!
 

rhawes

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Also I happen to have a corkbark elm that I have only had a month indoors and it seems to have leafscorch? How is this possible my room gets approximately 79 degrees F. and about 71% humidity. Have not fertilized until today. Any ideas what could be causing this?
 

Shibui

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Indoors is a difficult environment for most trees which are obviously adapted to outdoor conditions. What we consider bright conditions probably appear very dull to a tree that is adapted to full outdoor light. Unless you have made exceptional conditions for trees they do tend to struggle for light, humidity, etc.
Leaf scorch can be caused by a number of things as noted above. Indoors temp and sun are not factors but not enough water may be as we tend to water sparingly indoors to limit water spillage. Too much water may also be a cause - perversely, too much water can cause roots to rot so the tree cannot take in enough water causing leaves to brown. Humidity can be low indoors with heaters and AC reducing air moisture so trees can struggle to maintain correct humidity. See above about excellent conditions for plants being very different from excellent conditions for people.
 

Bonsai Nut

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It is a combination of low humidity, high heat and dry winds.
This is absolutely dead on. I think many people think of leaf scorch as being primarily sun related. When I lived in SoCal it was dry winds. I would keep Japanese maples from January - May in full sun no problem. But the first Santa Ana wind that blew in from the desert - they were toast.
 

WNC Bonsai

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I agree about the drying winds and humidity but here in the SE I doubt you will find low humidity an issue or I wouldn’t need to run a dehumidifier 24/7. The maples I have in shade don’t have any scorched leaves, only those in the sun, and I try to remember to move them into shade beginning mid-June but too often forget. Also it usually is the red leaves that scorch but nor the green ones. So check your humidity and stay out of the wind but as far as I am concerned get the m put of full sun.
 
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