Black tips on Trident leaves

[Daniel son STL]

Trident maples can survive temps from 0 F to 110 F and if given shade up to 120 F. But key is they need to adapt and harden off to outdoor conditions. When moving from inside to outside, only protect at night if the temps are below 40 F. Start out with afternoon shade. Watch how the tree responds. If you get sunburn leaves don't panic. New "outdoor grown leaves" will replace the tender indoor grown leaves. Make certain the tree gets shade during the hottest part of the Las Vegas day. Maples are forest trees, they are not desert cacti, they appreciate bright shade or dappled sun. Full desert sun will cook them, especially May through September. Once adapted to being outside, leave the tree outside to get the chill in the autumn. Frost and freezing in autumn will not harm the trident at all. Winter the tree by setting it on the ground IN THE SHADE of a building or a fence or wall. The shade will prevent it from getting sun scald on below freezing sunny days in winter.

Sun scald on the trunk?

 

[Leo in N E Illinois]

Sun scald on the trunk?

Sun scald in my climate is a winter problem. The ground is frozen and usually happens when the air is well below freezing. Direct sun on a frozen trunk warms the trunk just enough to dehydrate the trunk while frozen ground and roots do not allow sap to move. I suppose it can happen in the desert, desert sun is brutal, but the cause is different than what one would see in winter.

Honestly, it is difficult to keep maples happy in the desert. The native maples, like big leaf maple, are always in sheltered areas like box canyons, stream gullies, under shade of other trees or at elevation above the "desert floor".

So in Las Vegas, shade cloth is your friend, keep it shaded most of the day during the hottest 6 months of the year.

 

[Rob.t]

So looks like I ended up killing the maples. The soil ended up infested with white flies and worms. Let the soil dry out and repotted them, next morning found them a bit droopy , watered them and a day later leaves are wilted and dry.

 

[Shibui]

So looks like I ended up killing the maples. The soil ended up infested with white flies and worms. Let the soil dry out and repotted them, next morning found them a bit droopy , watered them and a day later leaves are wilted and dry.

White worms and flies sounds like fungus gnats. They love soggy, organic soil and thrive indoors. Exactly the opposite conditions that trees like. It is quite likely your seedlings already had rotting roots and could not cope with drier conditions or the out of season repot.
All is not lost however. Tridents are very tough. I have often repotted tridents in the growing season. The usual response is to drop leaves but most then grow new leaves a few weeks later.
Continue care for another couple of months before giving up on these.
Fingers crossed.

 

[Katie0317]

Spray the soil with a solution of water and dish soap. The recipe for killing white flies on bonsai is online but it's very straightforward. Google it just to get the proportions right. It's one tablespoon of dish detergent to one gallon of slightly warm water. There are eight glasses of 8 oz each in a gallon so you don't need to mix a full gallon. Just need a small spray bottle.

 

[penumbra]

A peroxide / water rinse (50/50) can be your friend here.