Hi, you don't say how often you do water, or whether the water soaks down through the soil, or just wets the top of it along with the foliage. Maples do like to dry a little between waterings, don't like to stay wet, but do need to be watered properly when it's done... though you may be doing a great job. The wind and heat may also be factors, but it's hard to tell from here. Where do you live?

Thanks for replying. I live in England. It has been very windy and hot so I think this is the main reason. The soil is almost always damp so maybe I need to let it dry a bit more between waterings. the water does soak sown through the soil so i think the drainage is ok. I live in a hard water area do you think this might make a difference?

Thanks again

Grant

I think you're either keeping the soil (right to the bottom) too wet all the time, which maples definitely don't like, or not actually getting water deep enough when you do water... which is hard to judge from here, but I doubt that 'hard' water would make a lot of diff., though maples don't need as high an acid content as conifers, azaleas, etc.

Grant,
Please define your leaf problems. Lucy's comment about the hard water is off base. More info please. If by hard you mean Iron, probably not a problem. If you mean lime it will actually raise the pH to high levels. Can't you collect rainwater in England?
Vernon

If it's leaf burn it could be your fertilizer. Don't use anything but organic on maples.
Hard water or wet soil WILL NOT cause it.

These look well on the way to being ex-trees.

Regular watering, in the shade, in a big terracotta pot with 1 little drainage hole in what looks like a heavy soil = possible root rot.

The red one atropurpureum? in particular looks like its got it.

I have made the mistake this year of watering a deshojo red maple that has a large root ball in old soil containing some peat in an old pot to death probably as I made no allowance for lower demands due to it being trunk chopped.

As they are this far gone, I'd be tempted to remove them from their pots and check if there is any healthy white roots there. You'd also get a chance to see how wet it is down there.

You may find that there is not much root too speak of.

You can try re-potting in new pots in a mix of 80% horticultural grit and soil conditioner (composted bark) making sure that there is plenty of gravel in the bottom of the pots to allow for drainage.

Give them a little drink every few days when the pots feel light.

Some people recommend watering with a fungicide.

I have all sorts of other acers getting a good dose of full sun and wind all day that are thriving - loving it in fact.

My back yard is a suntrap up into the 90s the last few weeks so I wouldn't say that was your problem.

Once the leaves have lost their vitality the sun and wind will turn them brown and crispy in as little as a few hours which is why an overwatering or root problem is often mistaken for underwatering. You then apply more water and total collapse can ensue.

thanks very much all I think tim moose is probably on the right lines and I will follow his advice.

When I say hardwater area I meant high Lime.

some of my other trees are suffering now aswell so I imagine it's down to over watering and not enough drainage.

Thanks very very Much

Grant

I dont' really think the real problem is over-watering, though the problem will cause this to be the factor that produces the symptoms you have exhibited. What kind of soil do you have the trees in and do the pots have ample drainage holes? (two questions) If your soil is not well drained it will tend to hold water longer than it should, especially near the bottom of the pot. The tree will exhibit the symptoms of over-watering which is not really the case the real problem is lack of adequate drainage.

Have you sprayed these trees with any kind of insecticides recently? Japanes Maples are sensitive to a host of chemical agents and you have to make certian you read the lables carefully, and ask for second oppinions on products you are not sure of.

Some sort of fungus is a possibility expecially if the soil is too wet or too compacted.

Vance Wood.