Change my last to r and I'm something colossal On my own, I can keep you dry at most

A trellis for growing flowers Hides in a small attic extension

I wear many layers but I’m not dressed for the cold. I’m round and I’m leafy, both humble and bold. I might roll in a patch or be chopped for a dish, From slaw to a stew, I grant cooks their wish.

It's inside a tree And sometimes seen at night It could mean a promise Or a place for a fight Put it on a finger The one that shares its name It could come from a phone Or be made for a game What am I?

I am a blade, but I do not cut. I am shaved for sport and smoked by others.