How to preserve local humidity outdoors and leaf health?

[justBonsai]

I have a lot of trouble with my deciduous trees by the time mid summer hits. In part this may be from fungus and disease as my maples will push out wrinkly or curly leaves--remedied with copper and systemic sprayings. The bigger issue is heat and by the fall, unforgiving dry winds. By the time my maples hit fall they have a lot of damaged or crispy leaves.

My maples did a lot better this year compared to last with more watering and placement in shade during peak temps but there are still clear signs of sun and wind damage. The worst of the damage was on my trident maple which was planted in the ground by a south facing wall. I got amazing growth and development but really bad leaf burn. I cut off several of my sacrifice branches and soon after a fall heat wave crisped up the leaves close to the trunk. The sudden removal of all this foliage prompted the tree to flush out new growth. The tree should still enter dormancy but it will definitely be late--probably by late November to early December unfortunately. The tree will be relocated by next spring.

My intention for next growing season is to put all my heat/wind sensitive trees in a specific structured area that would preserve its health during harsh wind and temps. I can control wind and sun with well placed shade cloth but humidity is a factor I want to increase some how. Would say putting containers of water within close proximity to the trees increase humidity during hot temps? A misting system is not an option for me right now so I'm looking for more creative approaches.

Any advice or help would be appreciated.

Thanks,
Julian

 

[BrianBay9]

Hi Julian. I'm sure moving these to a more controlled environment should help some. As they are now, that wall acts as a heat sink and sun reflector, probably increasing the temps around your plants significantly. Blocking the wind is certainly an improvement. Keeping the pots shaded or wrapped on hot days can help. I don't think open containers of water will do much for you. An automatic misting system is your best bet, but apparently not an option?

 

[GrimLore]

I have a lot of trouble with my deciduous trees by the time mid summer hits.

Your USDA Zone is roughly 10 I am in 6b-7 and I usually grow most all deciduous except willow, bald cypress, and some oaks in very filtered sun. You could liken it to 70 percent shade cloth as I used at my old house. Young Maples in particular do not like full sun and even more so potted. The fruit trees and many others don't like it either until larger and far stronger. I find the fruits do just fine in full sun after at least two seasons in filtered sun with one exception being apples...
All that being said the spot you have those in is really counter productive in your zone even in the ground. In the Spring I would pot them up in a fast draining nursery mix and at least 2 gallon containers. I would then move them under a large shade providing tree or similar. Seems to me they would/should recover good in two years with normal/proper care after which you could slowly acclimate most everything other then maples to a bit more sun.
Those look pretty tough from what I see and you describe but IMHO they need what I describe. It is not unusual for a tree to live for 3 -4 years in bad conditions but they will die...

Grimmy

 

[justBonsai]

Your USDA Zone is roughly 10 I am in 6b-7 and I usually grow most all deciduous except willow, bald cypress, and some oaks in very filtered sun. You could liken it to 70 percent shade cloth as I used at my old house. Young Maples in particular do not like full sun and even more so potted. The fruit trees and many others don't like it either until larger and far stronger. I find the fruits do just fine in full sun after at least two seasons in filtered sun with one exception being apples...
All that being said the spot you have those in is really counter productive in your zone even in the ground. In the Spring I would pot them up in a fast draining nursery mix and at least 2 gallon containers. I would then move them under a large shade providing tree or similar. Seems to me they would/should recover good in two years with normal/proper care after which you could slowly acclimate most everything other then maples to a bit more sun.
Those look pretty tough from what I see and you describe but IMHO they need what I describe. It is not unusual for a tree to live for 3 -4 years in bad conditions but they will die...

Grimmy

That trident is my only maple in that south facing position. The rest of my maples are in cooler areas with significantly less damage. I was just showing the trident as an example as the worst it could get. I will definitely be moving the tree next spring as in the ground at that position was not the best idea.

Oaks and elms do fine even in heat and sun. It's mainly just Japanese maples that give me the most trouble.

 

[Dav4]

That trident is my only maple in that south facing position. The rest of my maples are in cooler areas with significantly less damage. I was just showing the trident as an example as the worst it could get. I will definitely be moving the tree next spring as in the ground at that position was not the best idea.

Oaks and elms do fine even in heat and sun. It's mainly just Japanese maples that give me the most trouble.

Because of their finer foliage, they're the most likely of suffering the effects of hot wind mainly. Fwiw, I have many palmatums, including lace leaf varieties planted in full sun here in N GA and they do just fine and my tridents would like more. You live in a slightly hotter climate but one that probably has lower relative humidity. Throw in some wind and you've got leaf scorch

 

[BrianBay9]

Fwiw, I have many palmatums, including lace leaf varieties planted in full sun here in N GA and they do just fine and my tridents would like more. You live in a slightly hotter climate but one that probably has lower relative humidity. Throw in some wind and you've got leaf scorch

With respect, Georgia has WAY less UV radiation, WAY more humidity than Julian's location. He's always going to be battling leaf scorch.

 

[Dav4]

With respect, Georgia has WAY less UV radiation, WAY more humidity than Julian's location. He's always going to be battling leaf scorch.

Right, I understand that, and didn't mean to sound like he should be placing his maples in full sun and only worry about the wind...my mistake if it sounded that way. I just wanted to point out that there is a misconception that Japanese maples should always be protected from the sun, and can do well in full sun in certain microclimates. As you've pointed out, Bluemon's location will always be problematic for several reason's.

 

[justBonsai]

Right, I understand that, and didn't mean to sound like he should be placing his maples in full sun and only worry about the wind...my mistake if it sounded that way. I just wanted to point out that there is a misconception that Japanese maples should always be protected from the sun, and can do well in full sun in certain microclimates. As you've pointed out, Bluemon's location will always be problematic for several reason's.

Yeah Southern California does have a ton of micro climates and to place the whole southern part of the state under one climate zone really doesn't show the diversity we can have. I can grow a pretty wide variety of trees where I live but the more trees with more delicate foliage are finicky.