[mickeyboy]

Hi all i have 2 acers that appear to be either dead or dying... They started off budding and started to form leaves then for some reason once half formed they died.... I noticed a lot of tiny spider webs over it but couldnt find spiders....
They are now at the stage of having no leaves although a few buds appear to be trying to stem....
Any suggestions as to what is happening and any cures???

Cheers 

[Old Tom]

Have a good close look and see if you can spot any nasty little sap suckers. My bonsal acers are prone to attack from red spider mites and scale insects as well as the more traditional greenfly. They all drain the life out of the trees if they get the chance.

[Trillium]

Are these seedlings or young trees?

If seedlings, they cannot be kept in greenhouses, if that's the case. They must stay outside, and spaced for good air flow. Also, if potted, it could be a taproot problem or sowbugs have moved in and damaging the roots.
Young trees also need frequent watering.

[mickeyboy]

they are little trees, only about 20 inches tall. Just a shame as they did so well last year. I have them potted on the patio....

I couldnt see any little bugs on them just those lattle spider webs which i have now cleared away i hope.....

Cheers

[Trillium]

If they're going to be full grown acers, then the pots are far too shallow. Very carefully pull one out of its pot and see if the roots go round and round at the bottom.

Acers have very large tap roots, and even 3" ones in my yard are hard to pull out. If you've got this circling, which I suspect you have, the trees need to be planted out rather than kept in pots. Add some sort of protective wrap around the trees immediately on planting as rabbits adore young acer trees for snacks. My mum left hers overnight, thinking she'd wrap it in the morning and it was too late. Five times 

Until you plant them out, they'll continue to decline and soon die.

[Goosegirl]

I have heard that, when re-potting acers, don't upgrade to too big a pot as it can kill them - don't know the reason.