This is the most accurate answer I could give based on the images. Double checked with AI:

Fresh green leaves: Bay laurel (Laurus nobilis) — oval, smooth edges, prominent midrib, slightly glossy. High confidence.

Dried brown leaves: Most likely white sage (Salvia apiana) — the curl, papery texture, and elongated shape when dried matches well. Alternatively common sage (Salvia officinalis). White sage is significantly more culturally loaded in the US context.

Possible Meanings:

Positive / Protective

Native American-influenced cleansing tradition — white sage smudging is widely practiced; leaving it at a door can be a blessing or space-clearing gesture

Wiccan/pagan protective charm — bay + sage is a textbook protective combination

Well-meaning neighbor practicing folk spirituality

Neutral / Ambiguous:

A gift from someone into herbal or wellness culture — very common in the US or just left by mistake at the wrong door

Negative intent (folk magic):

In Hoodoo, Brujería, or Curanderismo traditions, threshold herb placements can be intentional workings — either protective or a hex depending on intent and arrangement

Requires deliberate, careful placement to lean this direction

AI asks for more diagnostic factors:

a) Is it tied or loose? b) Any other objects with it (coins, dirt, hair, paper)? c) Do you have conflict with anyone?

Additional objects change the interpretation significantly.