I'm stumped

[Mainer]

I suspect that these massive leaves are the effort of a tree to regenerate from a stump. I just need to know what species of tree.
Photographed in Portland, Maine.

 

[cpp gardener]

Looks like Oakleaf Hydrangea, Hydrangea quercifolia.

 

[Mainer]

Hydrangea quercifolia

Thank-you! It's native to the southeast, but I found an article confirming that there are outliers here in New England.
"Oak-leaved hydrangea is most common in the southeast U. S., but is recorded from a few roadside localities in New England. It produces conical spires of showy white flowers in May to July, which gradually turn pink during the growing season. The deeply lobed leaves of this species resemble those of oak, and turn a pleasing crimson-purple color in the fall. The peeling bark of older plants adds visual interest in the garden."
https://gobotany.nativeplanttrust.org/species/hydrangea/quercifolia/

 

[Oliver Buckle]

Sounds like quite a nice thing to have, if it is in the right place.

 

[Avi]

We had a growth of Oak-leaf Hydrangea at our house that we recently moved from...Here it is when in season and in bloom for comparison

 

[Meadowlark]

It not only looks like it...it is oak leaf hydrangea, IMO.

Here is mine today...a perfect match for the Op's photos by comparison: