HI Jack. the problem you are having with your maples is common. I have several japanese maples of different types (bloodgood, lace leaf, ect. )and they all do the same thing you have just discribed. I have all of my maples in pots so I have experimented a bit from year to year trying to see if the amount of sun they receive at different times of the day have any effect on this. the one thing that I have noticed is the trees that get filtered sunlight ONLY all day are the ones that get scortched less if any at all. I live in Texas so the sun here is brutal. you might try leaving all of them that you can in a shaded or filtered area starting just before spring. good luck keep me informed.

I've grown potted/bonsai maples in full sun as well as under 50% shade cloth. In full sun, I was watering 6 times a day at the height of summer, and under shade cloth only 3-4 times.

{{gwi:1010917}}

Hot winds and lack of moisture are a bigger threat than full sun for leaf margin burn, and trees growing in the ground would also benefit from windbreaks and extra watering.

As maples grow virtually throughout summer, healthy trees which are in bonsai training can be defoliated (leave the petioles) in mid summer - this will induce a new crop of leaves which will also have a more intense coloring (than if the first crop of leaves were left till autumn).. depending on timing, they will also be of a smaller size

{{gwi:1010918}}

Start tapering off the watering towards the end of summer, keeping the bonsai in a dryish condition pre- autumn (though not allowed to completely dry out) and this will also help to produce the most intense color

Jack

Hi,

I live in Los Angeles and have pretty much the same climate Jack. My question is whether and at what point scorched leaves should be removed. Usually the browning starts at the leaf tips and progresses inward until the whole leaf dies. Should I cut them when they first show signs of damage? Or should I cut off the damaged tips? Or just leave them alone?