Big ol' Morus alba...

I'm wondering about the leaf arrangement. I can only see one leaf junction but it appears to be opposite. I don't see mulberry seedlings here so am not familiar with them but isn't the norm alternate? Are they sometimes opposite?

Lookup says Morus leaves are alternate, but that sure looks like a mulberry leaf. Stumped.....

As someone (!) commonly laments... Show us the whole plant.

If truly opposite, then of course Morus sp. should not be considered.

I can see two leaves directly opposite each other in the OP's picture.

Any Hydrangeas in the vicinity?

Or Viburnums?

The plot thickens!

Something instinctively told me it didn't seem like the other Morus seedlings I'd seen, but I admit I gave absolutely zilch thought to alternate vs. opposite.

There is a Hydrangea 'Honeycomb' about 6 feet away. Now I'm wondering, could it just be a very distant sucker!? I've never seen a Hydrangea sucker anywhere near that far, but, OTOH, I have more far experience with mopheads than H. paniculata...'Honeycomb' is the only PG I've grown at all.

OTOH if it is a seedling, it is 100% a first time occurrence for me. NEVER seen Hydrangeas self seeding in my garden. I wouldn't have even considered that, but, now that I think about it, it could make sense I suppose. Floral do mopheads self-sow in the mild climate of SW UK? They certainly do in the Azores LOL. So far my most 'aggressive' ornamental self seeder is...drumroll please...camellias.

Now I think I'll dig it up tomorrow to see if it's attached to 'Honeycomb', if not, plant it somewhere else. No harm in seeing if it has some desirable trait.

Some of the Hydrangea leaves on a search page do look similar.

https://duckduckgo.com/?t=ffab&q=Hydrangea+leaf&atb=v252-1&iax=images&ia=images

I have no experience with self seeding Hydrangeas, in fact they are not much grown in my area, but I do know that mop head 'flowers' are largely sterile. And they will root where branches touch the ground, or even, in the right climate, from dropped prunings.

Honeycomb is not a macrophylla afaik, so it may well set seed.

Showing us more pictures would help clear up the speculation.

I'm not going to dig it up until we get some rain. Soil is bone dry RN. Driest November I can remember.