These plants have evolved unique structures—swollen stems, hollow thorns, or even bulbous roots—that act as living homes for entire ant colonies.

One of the weeds that won’t be easy to pull is catbriar, or smilax. It has shiny heart-shaped leaves and a twining stem with thorns.

One of the weeds that won’t be easy to pull is catbriar, or smilax. It has shiny heart-shaped leaves and a twining stem with thorns.