Why is my acer two colours?

[AncientAzalea]

I adore this acer that we inherited when we moved here but I wondered if anyone could explain why it has this pretty green bit at the bottom. It's coming from the main branch.

Hybrid?

It’s because these highly decorative, coloured leaved Acers are grafted onto more sturdy stocks. The stocks sometimes throw out suckers (much like hybrid tea roses do), and that is the green growth you can see.

If left on the plant, they can gradually take over, being more vigorous, so it’s best to remove the rogue stem close to the stem.

Yes it will be growing from beneath the graft - I have one which does this. You need to remove the green leaves.

Yes, as already pointed out, it is coming from below the graft. Most fancy varieties of acer don't do as well on their own roots, so the stems are grafted low down onto the rootstock and trunk of a robust variety, usually the basic green job.

You need to get down there and cut all the green stems right off where they meet the trunk, otherwise they will take over and sap all the energy from the section above the graft.