Learn Spanish (Latin America): ¿Puedes oler el jazmín desde allí?

You use oler on its own when a person or animal is actively sniffing or detecting a scent, just like smelling the jasmine here. You use oler a when a subject gives off a scent (to smell like something). If you said ¿Huele a jazmín desde allí?, it would change the meaning to 'Does it smell like jasmine from over there?'

Could I say de allí instead of desde allí?

You could, but desde allí is much more precise here. Desde emphasizes the physical vantage point or the exact point in space where the listener is located. De is usually used for origin (where someone or something fundamentally comes from).

How do I choose between ahí, allí, and allá for 'there' in a sentence like this?

Generally, ahí is a place close to the listener ('right there where you are'), while allí and allá refer to a place further away from both speakers ('over there'). While ahí would make perfect sense here if you are asking someone standing somewhat near the plant, using allí emphasizes that the listener is at a specific, distant location from the speaker.

Why does jazmín have a written accent mark?