By Jwc
United Kingdom 
I have had a variegated maple in my garden for twenty years - at least until this year it was. I know about pruning out the green stuff and did it regularly whenever the need arose. There was slightly more reversion last year (probably about 5%) than usual but I got rid of it. This year however it has come out almost totally green (there's about 2% of variegated branches). What could cause this sudden and overwhelming reversion and is there anything that can be done?
22 Jun, 2012
Answers
If you examine the leaves closely, you might see that there is a bit of variation - but its so slight, you can't see it from couple of feet away. That's certainly how my variegated acer looks this year - a bit of variegation towards the front, but the rest looks more or less plain green - not enough sun.
23 Jun, 2012
Many thanks Bamboo and Pamg - Not enough sun would certainly be the case here? And there is dark as opposed to usually very light) variegation. Does that mean things will be "back to normal" next year do you know? I usually prune out any strong green in midsummer but I'm afraid to touch it at the moment
23 Jun, 2012
I think you should take out any plain green growth because if left it will revert to the plain green. I saw this problem over the road from me. The person cut out all green leaves - it looked pretty bare for a while but later the variagated appeared again. So drastic might work!
23 Jun, 2012
I was just looking at mine and won't touch it yet, the back is worst as its in shade but slight variegations are on some.....
23 Jun, 2012
All the time you can see some sort of variegation on the leaves, I wouldn't remove them. If you've got a branch with totally plain leaves, remove that. With any luck, we'll actually have a summer next year and it will be much better!
23 Jun, 2012
There have been quite a few questions about this, consensus of opinion is. "we need more sun!" My 'drummondii' is just the same
23 Jun, 2012