"Mike Lyle" wrote in message
om...

[snip]

I'd also guess (but it's only a guess) 40 cm is too big a pot: best
way is the old rule of patiently going up one size at a time, and
only
when the roots have definitely reached the outside of the old pot,
so
that any water you give will immediately go to the plant, rather
than
hang about going stagnant. (Some people, in this group notably
Franz,
ignore this rule without ill effect; but they have a watering regime
to suit.)

That is an urban legend. If there were any truth in it, all plants
planted in the open ground, which is an infinite sized pot for
practical purposes, should fail.

I planted a very young Acer palmatum atropurpureum directly in a 45 cm
pot about eight years ago and have never repotted it. It thrives.

Franz