adventive

Accidental.

Adventitious.

For Hvmane Knovvledge, Which Concernes the mind, it hath two parts, the one that enquireth of The Svbstance, Or Natvre Of The Sovle Or Mind; The other, that enquireth of the Facvlties Or Fvnctions Thereof: vnto the firſt of theſe, the conſiderations of the Originall of the ſoule, whether it be Natiue or aduentiue; and how farre it is exempted from Lawes of Matter; […]

Of a plant: not native, but introduced by humans to a place and since naturalized.

A non-native plant that has become naturalized.

Such interlopers are known as exotics, adventives, or aliens, all terms that may be considered synonymous with "nasty.